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HomeMy WebLinkAboutAPA1723f Series 1959, No. 25 Issued September 1963 s 599 .A4 F3 . 1963 Fairbanks Area Alaska UNITED STATES DEPARTMENT OF AGRICULTURE Soil Conservation Service In cooperation with ALASKA. AGRICULTURAL EXPERIMENT STATION HOW TO USE THE SOIL SURVEY REPORT T IDS SOIL SURVEY of the Fair- banks Area, Alaska, will serve several groups of readers. It will help farmers m planning the kind of management that will protect their soils and provide good yields; 8$Sist engineers in selecting sites for roads, buildings, ponds, and other struc- tures; add to our knowledge of soil sci- ence; and provide general information about this part of Alaska. Soil scientists studied and described the soils and made a map that shows the kind of soil everywhere in the Area. The base for the soil map is a set of aerial photo- graphs that show roads, streams, houses, forests, and many other landmarks. Locatinq Soils Use the index to map sheets at the back of this report to locate areas on the large map. Tlie index is a small map of the county on which numbered rectangles have been drawn to sho;w where each sheet of the large map is located. When the cor- rect sheet of the large map has been found, it will be seen that boundaries of the soils are outlined, and that there is a symbol for each kind of soil. All areas marked with the same symbol are the same kind of soil, wherever they occur on the map. The symbol is inside the area if there is enough room; otherwise, it is outside the area and a pointer shows where the symbol belongs. Findinq InformaH.on This report contains sections that will interest different groups of readers, as well as some sections that may be of interest to all readers. Farmers and those who work with farmers can learn about the soils in the section "Descriptions of the Soils" and then turn to the section "Use and Manage- ment of the Soils." In this way, they first . identify the soils on their farm and then learn how these soils can be managed and what yields can be expected. The "Guide to Mapping Units and Management Groups" at the back of the report will simplify use of the map and report. This guide lists each soil and land type mapped m the county, and the page where each is described. It also lists, for each soil and land type, the management group and the page where each group is described. Engineers will want to refer to the sec- tion "Engineering Applications." Tables in that section show characteristics of the soils that affect engineering. Scientists and others who are interested will find information about how the soils were formed and how they were classified in the section ''Formation, Classification, and Morphology of the Soils." Students, teachers, and other users will find information about soils and their management in various parts of the re- port, depending on their particular mterest. Newcomers in the Fairbanks Area will be · especially interested in the section "General Characteristics of the Area " which gives additional information abo~t the Climate and other features. * *· * "' "' Field~ork for this survey was com- pleted m 1959. Unless otherwise indi- cated, all statements in the report refer to conditions in the Fairbanks Area at that time. . The soil survey of the Fairbanks Area Is part of the technical assistance furnished by the Soil Conservation Serv- ice to the Fairbanks Soil Conservation Subdis~rict. Help. in farm planning can be obtamed from the staff of the Soil Con- servation Service assisting the subdistrict. Hell? in other agricultural problems can be obtamed from the extension agent the State Agricultural Experiment Stdtion, and other agencies in the Area. UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1963 ARLIS Alaska Resources Library & Information Servk AnchoraP"e. AK I I I ·c.o. : 0 Cl) C\1 C\1 C\1 T"" 0 0 LO LO !'- ('I) Cl) Contents G~neral characteristics of the Area _________________ _; ______________ _ Geology _____________________________________________________ _ Clilnate _____________________________________________________ _ Temperature characteristics __________________________________ _ Precipitation characteristics __________________________________ _ Vegetation ___________________________________________________ _ VVildlife _____________________________________________________ _ History, settlement, and industry _________________________________ _ Agriculture _____________________________________________________ _ How soils are named, mapped, and classified _______________________ _ Soil groups _____________________________________________________ _ Descriptions of the soils _________________________________________ _ Jlliuvialland __________________________________________________ _ Bradway series _______________________________________________ _ Chena series _________________________________________________ _ Ester series __________________________________________________ _ Fairbanks series ______________________________________________ _ Gilmore series_____ _ _ ________________________________________ _ Gold::Meam series _____________________________________________ _ Gravel pits ___________________________________________________ _ Lemeta series ________________________________________________ _ . ~~~~ot:~;~~~================================================== Salchaket series _______________________________________________ _ Saulich series _________________________________________________ _ Tanana series ________________________________________________ _ Use and management of the soils _________________________________ _ Clearing land _________________________________________________ _ Crop yields and fertilization ____________________________________ _ Capability groups of soils ______________________________________ _ NJ;anag~ment ~y g~oups of soils _________________________________ _ Engmeermg applications _________________________________________ _ Engineering soil classification systems ___________________________ _ Soil characteristics significant to engineering _____________________ _ Soil test data _________________________________________________ _ Formation, classification, and morphology of the soils _______________ _ Factors of soil formation _______________________________________ _ Classification and morphology __________________________________ _ Subarctic Brown Forest soils __________________________________ _ Alluvial soils _______________________________________________ _ Low-Humic Gley soils _______________________________________ _ Bog soils ___________________________________________________ _ Literature cited _________________________________________________ _ Guide to mapping units and management groups ___________________ _ Page 1 1 2 2 3 4 5 5 5 6 6 8 10 10 10 10 11 12 13 14 14 14 14 15 15 16 16 16 17 17 19 22 23 23 31 34 34 34 34 37 37 39 40 41 Series 1959, No. 25 Issued September 1963 ARLIS Alaska Resources Library & Information Scrvic•. Library Builtling, Suite Ill 3211 Provitlcncc Drive Anchorage, AK 99508--l614 I SOIL SURVEY OF FAIRBANKS AREA, ALASKA BY SAMUEL RIEGER, JAMES A. DEMENT, AND DUPREE SANDERS, SOIL CONSERVATION SERVICE REPORT BASED IN PART ON EARLIER SURVEYS BY THOMAS H. DAY, THEODORE W. ANDERSON, ROBERT A. BOWEN, WILLARD A. CALL, M. GRANT LINDSAY, H. DALE MUNK, FRANK B. TAYLOR, GEORGE A. WOODRUFF, SOIL CONSER- VATION SERVICE, AND NEIL MICHAELSON, ALASKA AGRICULTURAL EXPERIMENT STATION UNITED STATES DEPARTMENT OF AGRICULTURE, SOIL CONSERVATION SERVICI!:, IN COOPERATION WITH ALASKA AGRICULTURAL EXPERIMENT STATION T HE FAIRBANKS AREA is the most densely pop- ulated and most intensively fanned part of central Alaska. Its center is the city of Fairbanks, which is the commercial hub of interior and northern Alaska and the second largest city in the State. The Area includes all but a small part of the Fairbanks Soil Conservation Sub- district. It extends from a line 12 mile..c; west of the Fair- banks meridian to a point on the Chena River 36 miles east of the meridian. It is bounded on the south by the Tanana ~iver and on the north by a line 6 miles north of the Fairbanks base line. In all, 255,536 acres of land are in the Area. Streams and lakes amount to an additional 2,167 acres. The boundaries and the location of the Fair- banks Area are shown on the map on the back cover of this report. General Characteristics of the Area A broad, level flood plain borders the Tanana River and its main tributary in this Area, the Chena River. A nar- rower flood plain borders Goldstream Creek in the north- western part of the Area. Adjoining the flood plains of these streams are the hills and ridges of the Yukon-Tanana upland. As a rule, gently sloping alluvial fans lie between the flood plains and the hills, but in many places, the transition between levelland and steep hills is abrupt. At Fairbanks, the flood plain is less than 450 feet above sea level, whereas the summits of some hills in the Area are more than 1,800 feet above sea level. Geology Part of the Fairbanks Area is on the Yukon-Tanana upland, and part is on the flood plain$ of the ·Tanana River and a major tributary, the Chena River. The country rock of the uplands near Fairbanks is Birch Creek schist, a Precambrian formation made up mainly of folded and strongly jointed quartz-mica and quartzite schist (5, 9, 14, 15) .1 Many veins of quartz in the schist contain gold. A few masses of granite, quartz diorite, and basalt are exposed locally. 1 Italicized figures in parentheses refer to Literature Cited, p. 40. On the lowlands along the Tanana River, large quanti- ties of glacial outwash have been deposited. The Fair- banks Area has never been glaciated, but the Tanana River carries large quantities of outwash material from glaciers in the Alaska Range to the south. When glaciation was at its maximum, several hundred feet of gravel and sand was deposited in the flood plain of the Tanana River. This deposit was later covered by layers of finer alluvial sand and silt, a few inches to many feet thick. The uplands are almost everywhere covered by a mantle of micaceous loess that blew in from the outwash plains of the Tanana Valley ( 8). On the high ridges, the loess is about 1 foot thick; on the low hills near the Tanana River, it is up to 200 feet thick. The loess consists of silt-size particles of quartz, feldspar, and muscovite from 0.002 to 0.05 millimeter in diameter. Much of the loess has moved from the hillsides and has accumulated on the lower slopes and in the narrow upland valleys. As a result, the lower ends of the valleys along streams that flow into the Tanana River now have more than 300 feet of colluvial silt. Lenses of organic material occur throughout the rede- posited silt, which is known locally as muck. Minor earthquakes are fairly common. They are caused by movement deep in the earth related to the continuing upthrust of the Alaska Range to the south. Permafrost underlies most of the flood plains. It is also under the alluvial fans, the bottoms of drainageways in uplands, and the north-facing slopes. The upper limit of perennially frozen ground ranges from less than 2 feet from the surface in the silty alluvium on the older parts of the flood plains to more than 40 feet where the native vegetation has been cleared for a long time. Pennafrost is absent on moderately to steeply sloping south-facing hillsides and in places on the flood plain along the Tanana and Chena Rivers and their trihutaries. On the flood plains, ice occurs in the forms of fine lenses and "cement" between . mineral grains. On colluvial slopes, however, it occurs commonly as large ice masses under the redeposited loess ( 7). In shallow loess on steep, north-facing slopes, only a thin layer above and in the weathered bedrock is perennially frozen. The permafrost table is lowered when the natural vegetation and the insulating mat of moss on the soil surface are removed by fire or in clearing. 1 2 SOIL SURVEY SERIES 1959, NO. 25 Thermokarst topography is caused by the melting of large masses of underground ice on colluvial slopes. This type of topography is characterized by steep-walled sink- holes or an extremely hummocky soil surface. Cultivation may have to be abandoned on some cleared fields where this condition is severe ( 7) . Climate 2 The Fairbanks Area is near the center of the Climato- logical Division known as the Interior Basin of Alaska. This part of Alaska has extreme seasonal variations in temperature. Nearly all of the extreme temperatures for Alaska have been recorded in the Interior Basin. Climatic data for three stations in the Fairbanks Area are shown in table 1. The record high of 99 degrees, recorded in the Area at the University Experiment Station in July 1919, is just 1 degree less than Alaska's record high of 100 degrees, recorded at Fort Yukon in June 1915. The record low of 66 degrees below zero for the Area was recorded at the University Experiment Station and the Weather Bureau in Fairbanks in January 1934. Daily minimum readings drop to zero degrees or colder more than 75 percent of the days from November 1 to March 31. Daily maximum 'This section was prepared by C. E. WATSON, State climatologist, U.S. 'Veather Bureau, Anchorage, Alaska. readings reach 70 degrees or higher about 56 percent of the days in July and August. Temperatures reach 90 de- grees and higher at some time during about 20 percent of· the days in the growing season. The growing season is more sharply defined than in most agricultural areas, as there is a rapid change from the warm to the cold seasons. Terminal dates of the warm season fall rather dependably within narrow limits. The dates for freeze-free periods shown in table 2 are a fairly dependable guide for agriculture and other activities. Rapid growth of crops should be maintained, so that they can mature in the short growing season. However, the growth of crops is accelerated by the many hours of avail- able sunshine. During the months of June, July, and August, possible sunshine averages slightly more than 19 hours per day. As a result, the growth and maturity of crops is extremely rapid, particularly if t~mperature and moisture conditions are favorable. Temperature characteristics Table 2 shows, for two weather stations, the terminal dates of the season and the number of days between ter- minal dates, at specified temperatures of 32, 28, 24, 20, and 16 degrees. Data in this table indicate that the University Experiment Station, situated on a slope near the boundary between the uplands and the alluvial plain, has an average. freeze-free period of 88 days. The U.S. Weather Bureau Airport Station, situated on the alluvial plain, has a freeze-free period of 106 days. TABLE 1.-Temperature and precipitation, Fairbanks Area, Alaska University Experiment Station, College, U.S. Weather Bureau Airport Sta- Alaska; elevation, 481 feet; data for tion (Intern:;ttional Airport), Fair- period 1931 through 1960 banks, Alaska; elevation, 436 feet; data for period 1934 through 1960 Month Temperature Precipitation Temperature Precipi- tation Aver- Aver-Aver- Aver-age Aver-Aver- Aver- Aver-age age Aver-age pan Aver-age age Aver-age age maxi-mini-age 1 snow-evap-age maxi-mini-age 1 snow- mum mum fall ora-mum mum fall tion ------ oF. oF. oF. Inches Inches Inches' oF. oF. . oF. Inches Inches December ______ -6.8 1.5 -Hi.l 0. 57 8. 7 (3) -8.9 -0.6 -17.2 0. 49 9. 0 January _______ -7.3 1.6 -16.2 . 83 13. 1 (3) -10.5 -1.2 -19.7 . 90 14.0 February __ -~-_ . 8 11. 4 -9.8 . 51 7. 7 (3) -2.4 9. 2 -13.9 . 47 7. 7 March _________ 12. 7 25. 8 -. 5 . 42 5. 5 (3) 8. 7 22. 8 -5.4 . 43 7. 0 ApriL _________ 30. 7 43. 8 17.6 . 24 2. 3 (3) 29. 9 41. 8 17. 9 . 26 3. 1 May __________ 47. 0 60. 5 33. 5 . 80 .3 4. 21 47. 4 59. 1 35. 7 . 72 .4 June __________ 58.0 72. 0 43. 9 1. 48 0 5. 02 58. 9 70. 9 46. 8 1. 36 (4) July ___________ 59. 8 72.9 46. 6 2. 10 0 4. 31 60. 2 71. 5 48. 9 1. 86 0 August ________ 54. 8 66. 7 42. 8 2. 44 (4) 2. 71 54. 8 65. 5 44. 1 2. 12 (4) September _____ 44. 3 55. 2 33. 3 1. 36 .4 1. 31 44. 1 54. 0 34. 2 1. 12 . 6 October ________ 27. 2 36. 1 18.2 . 93 9. 3 (3) 26. 6 34. 6 18. 5 . 86 9. 5 November _____ 5. 5 13. 7 -2.7 . 63 8. 8 (3) 3. 5 11.6 -4.7 . 62 9. 3 --------- Year ______ 27. 2 38. 4 16.0 12. 31 56. 1 (3) 26. 0 36. 6 15. 4 11. 21 60. 6 I Inches of water. 2 Inches of water. Length of record ranges from 12 to 26 years. 3 Data not available. • Trace. College Magnetic Observatory, U.S. Coast and Geodetic Survey, Col- lege, Alaska; elevation, 621 feet; data for period 1949 through 1960 Temperature Precipi- tation Aver-Aver-Aver- Aver-age age Aver-age age maxi-mini-age 1 snow- mum mum fall ----- oF . oF. oF. Inches Inches -6.7 -0.1 -13.3 0.66 11. 7 -7.2 . 2 -14.5 . 91 15. 2 -2.8 6. 0 -11. 5 . 64 10. 8 12. 3 23. 4 1.2 . 32 5 .. 3 29. 5 40. 1 18. 8 . 13 1.2 47. 0 58. 2 35. 8 . 67 .5 57. 4 69. 2 45. 8 1. 57 0 59. 5 70. 4 48. 6 2. 37 0 55. 4 65. 9 44. 9 1. 80 (4) 43. 9 53. 2 34. 6 1. 34 .8 25. 3 32. 8 17. 7 . 66 7. 5 7. 2 14. 1 .4 . 53 8. 4 ----- 26. 7 36. 1 17. 4 11. 60 61. 4 FAIRBANKS AREA, ALASKA 3 TABLE 2.-Average dates, for beginning and end of sea-200 v son, at which temperature is equal to or above the oF. indicated University Experiment Station, College I Tempera- ture limit Terminal dates Number of days oF. 32 _______ May 29 to Aug. 88 24. 28 _______ May 18 to Sept. 114 9. 24 _______ May 9 to Sept. 134 20. 20 _______ Apr. 26 to Oct. 158 1. 16 _______ Apr. 24 to Oct. 165 6. I Data period, 1931 through 1960. 2 Data period, 1934 through 1960. U.S. Weather Bureau Air- port Station, Fairbanks 2 Terminal dates Number of days May 19 to Sept. 106 2. May 7 to Sept. 129 13. Apr. 29 to Sept. 148 24. Apr. 22 to Oct. 162 1. Apr. 19 to Oct. 171 7. For concurrent periods, the average minimum air tem- peratures at the University Experiment Station are gen- erally lower than those observed at the lower lying U.S. Weather Bureau Airport Station. There is little recorded evidence that cold-air drainage has a pronounced general effect in the vicinity of Fair- banks or College, Alaska. This does not mean that cold- air drainage does not affect local areas. The lowland along Goldstream Creek, for example, is rimmed by high ridges and doubtless has pronounced downslope air drain- age. This air drainage is capable of producing colder temperatures and a shorter growing season on the lowland than at either the University Experiment Station or the U.S. Weather Bureau Airport Station. · The probability of having seasons of various lengths in which the temperature will not fall below stated limits is shown in figures 1 and 2. This information is valuable to farmers and others who need favorable temperatures to operate outdoor enterprises. A farmer in the vicinity of the University Experiment Station (fig. 1) can expect, for example,. about half the time, or 5 years out of 10, a growing season of 88 days in which the temperature will not fall below 32 degrees. In only 2 years in 10 can he expect a season of 110 days in which the temperature will not fall below 32 degrees, but in 9 years out of 10 he can expect a season of 56 days in which thetemperature will not fall below 32 degrees. A farmer near the U.S. Weather Bureau Airport· Station can expect slightly longer. seasons than one near the University Experiment Station, and he can determine similar probabilities for his area by referring to figure 2. Precipitation characteristics Precipitation in the early part of the growing season, or in June, averages considerably less than that received in the eastern parts of IV"yoming and Colorado, or in the western parts ,of the Dakotas. The relatively short grow- ing season makes it imperative that plants grow rapidly all season if they are to mature. Although precipitation leO 160 (/) ~ 0 .z140 0 (/) <( ~ 120 LL 0 ~ 100 (!) z w ...J eo 60 40 / ~ ~ v v / v ..,. / V' v L / v ~ L /. ~ v ~ / v v v ..,. y / roo v / ~ v v /_ ~Or~v / v / v / ./ _,/ L ~~ '/ ~ / / v 0 ~q; ......... /'/ v v 9e 95 90 eo 10 60 50 40 30 20 10 5 2 PROBABILITY, PERCENT Figure I.-Probable number of days per year that temperature will not drop below 16, 20, 24, 28, or 32 degrees F. at the Univer- sity Experiment Station, College, Alaska. Based on records for 200 leO (/) ~ 160 0 z 0 (/) 140 <( w (/) LL 0 120 ::r: 1- (!) ~ 100 ...J eo 60 period 1931 through 1960. Elevation 481 feet. / io""" ~ v / / / / / v / I' / v v / 0 ..,.v v ..... ~:' ~ y ,. v / ?t:/ / v ~ / / ..,. v ., v v ,. / ~~ , v / v / ./ v /I' v ,.,..,.. ..,./ / ;.~ , v v / .,.,. .,.... 9e 95 90 eo 10 60 50 40 30 20 10 5 2 PROBABILITY, PERCENT Figure 2.-Probable number of days per year that temperature will not drop below 16, 20, 24, 28, or 32 degrees F. at the U.S. Weather Bureau Airport Station, Fairbanks, Alaska. Based on records for period 1934 through 1960. Elevation 436 feet. 4 SOIL SURVEY SERIES 19 59, NO. 2 5 is apparently deficient in the early part of the growin.g season, crops generally grow fast enough to mature. This growth indicates that there is enough early spring mois- ture in the soil to allow crops to grow rapidly. Frost melting in the subsoil is also a source of moisture for grow- ing crops in the first part of the season. Potential evapotranspiration in this Area has not been accurately determined, but preliminary computations by use of the Thornthwaite (11) method indicate that the po- tential (maximum) evapotranspiration is about4% inches per month in June and July and slightly less than 4 inches 111 August. Table 3 shows probable monthly precipitation at the University Experiment Station for May to Sep- tember, inclusive. Most of the rain in this Area falls during the growing season, and the amount may vary greatly within short distances. It is believed that most of the summer rain originates as moisture vapor in the Interior Basin. The frequency and intensity of showers tend to increase as the summer season progresses. The average month!y precipi- tation is less than one-fourth inch in April but increases to slightly more than 2lk inches in August. Data on pre- cipitation intensity are limited, but reliable, unofficial measurements indicate that rates of about 2 inches per hour have occurred in the Fairbanks Area for a penod of 30 minutes. An average of about eight thunderstorms occur during the summer. Hailstorms occur almost every summer, but the hailstones are seldom large enough to cause extensive damage. Tornadoes are practically un- known. Snowfall averages about 50 inches per year at the University Expe1·iment Station, and about 60 inches at the U.S. Weather Bureau Airport Station. However, total snow was 126 inches at the University Experiment Station and 135 inches at the U.S. Weather Bureau Air- port Station during the winter of 1936-37. Snow is usually on the ground from mid-October to mid-April. The maximum depth of snow on the ground during the winter averages between 25 and 30 inches. Wind velocity is usually low. The U.S. Weather Bu- reau Airport Station records an average annual wind velocity of 5 miles per hour. Winds are seldom strong enough to erode the soil severely. Winds are mainly from the north and northwest, but in June, July, and August they are mostly from the southwest. TABLE 3.-M onthly precipitation probability, University Experiment Station [1906 through 1960] 1 year in 10 2 years in 10 years will have--years will have-- Month Median I Less More Less More than-than-than-than- I ~Iay _____________ l Inches Inches Inches Inches Inches 0. 2 1.4 0. 7 0. 3 1. 1 June _____________ \ .5 2. 5 1.4 .8 2. 2 July _____________ .6 3. 8 1.9 .9 2. 8 August_ __________ .9 3. 6 2. 0 1. 1 3. 1 September_ _______ 1 .4 2. 5 1. 3 .6 1.8 1 The midpoint of total monthly precipitation. Half the time the total monthly precipitation can be expected to be above this figure, and half the time, less. Vegetation 3 Most of the Fairbanks Area is forested. Well-drained soils of the uplands and alluvial plains are covered mainly by white spruce, paper birch, and quaking aspen. Balsam poplar is common near streams. Imperfectly drained soils of the alluvial plains are generally covered by a dense growth of scrubby white spruce, black spruce, paper birch, willow, and tamarack. Poorly drained soils of uplands and plains support a sparse stand of black spruce and a dense undergr:owth of shrubs. Imperfectly and poorly drained areas normally are covered by a thick mat of moss. The climax forest on all well-drained soils in the Area is the white spruce type. It is believed that this forest type, once established, will reproduce itself ·and not change unless the stand is destroyed by fire or cutting. Immedi- ately following fire, most areas are invaded by the pioneer species-paper birch and quaking aspen. Areas that have been repeatedly burned by severe fire, however, may be occupied mainly by black spruce. Other plants that are abundant immediately after fire are Sitka alder, willows, bunchberry dogwood, wild rose, lingenberry, bluejoint, and fireweed. In stands more than 80 to 100 years old, birch and aspen begin to decay and are frequently replaced by white spruce. Although birch and aspen are relatively short lived, nearly pure stands of these trees, or of mix- tures of birch, aspen, and white spruce, are dominant in the Fairbanks Area. Most of the Area has been burned or cut over within the past 75 years. As a rule, tree seedlings will survive only where min- eral soil is exposed. This fact suggests that without seed- bed preparation regeneration is apt to be a problem after logging. Aspen and willow, however, may reproduce by sprouts from stumps or by suckers from roots. Trees in a mature stand of white spruce may be more than 200 years old, more than 90 feet tall, and more than 20 inches in diameter, measured at breast height. Fully stocked stands of old white spruce may have a gross mer- chantable volume of more than 15,000 board feet per acre. Dominant and codominant trees in stands of pure birch at the rotation age of 90 years average 65 feet tall and 6 to 7 inches in diameter, measured at breast height. In a well-stocked stand of birch, the gross merchantable vol- ume is 2,000 to 2,500 cubic feet per acre at rotation age. The ground cover in forests is essentially the same in all established stands. The principal shrubs in the subor- dinate vegetation are lowbush cranberry or lingenberry ( V accinium vitis-idaea), highbush cranberry or moose- berry (Viburnum edule), wild rose (Rosa acicularis), bunchberry dogwood ( 0 ornus canadensis) , and crow berry (Empetrum nigrum). The forbs are mainly bristly club- moss (Lycopodium annotinum) , American twinflower (Linnaea borealis var. americana), northern comandra ( 0 omandra livida), creeping rattlesnake-plantain (Good- y era repens var. ophioides), horsetail ( E quisetum spp.), and fire weed ( E pilobium angu-8tifolium). Grasses and 3 This section is based largely on the work of H. J. LUTZ (4) and on information supplied by R. A. GREGORY, Alaska Forest Re- search Center, U.S. Forest Service, Fairbanks. FAIRBANKS AREA, ALASKA 5 grasslike plants occur in places. These include bluejoint ( 0 alamagrostis canadensis), altai :fescue ( F estuca al- taica), bluegrass (Poa spp.), and Bigelow sedge (Carew bigelowii). The most common mosses on the :forest floor are Hylocomium splendens, Pleurozium schreberi, and Hypnum crista-castrensis. Lichens include Peltigera spp. and Oladonia spp. Most plant roots, including those o:f trees, are in the mat o:f decomposing organic material on the soil surface. De- spite the shallow rooting habit o:f most trees, windthrow is only a slight hazard. Moderately well drained· and imperfectly drained soils may support :forests similar to those on the well-drained soils, but more often they support a scrubby noncom- mercial stand o:f trees consisting o:f black spruce and wil- low. Mosses cover the ground. Horsetail and grasses are commonly the principal plants in the subordinate veg- etation, but shrubs like those on well-drained soils are also present. Poorly drained soils with a high permafrost table gen- erally support a sparse, noncommercial stand o:f black spruce miXed with some willows and alder and an occa- sional paper birch. A thick mat o:f moss, most~y Sphag- num spp., makes up the upper part o:f the soil. Many lichens, including Oladonia spp. and Peltigera spp., grow in the mat o:f moss. This mat also supports a dense cover o:f shrubs, mainly bog birch (Betula glandulosa), spirea (Spirea beauverdiana), Labrador-tea ( Ledum palustre spp. groenlandicum) , lingenberry ( V accinium vitis- idaea) , bog bilberry ( V accinium ~tliginosum), cloudberry (Rubus chamaemorus), and crowberry (Empetrum ni- grum) . Tussocks o:f cottonsedge ( Eriophorum vagina- tum) are also common. . In many places, especially in low level areas on the alluvial plain, trees are virtually absent. In these areas, mosses, shrubs, and tussocks o:f cottonsedge are the vegetation. On the whole, little use is made o:f :forests in the Area. Although :four small sawmills are in operation, and many houses and barns have been built o:f logs, the production o:f usable lumber is small. Almost no use is made o:f trees other than white spruce. It seems likely, however, that the :forests in the Fairbanks Area and in other parts o:f interior Alaska may be an important :future source o:f pulpwood. Wildlife Most o:f the Fairbanks Area is still :forested, and wild- life is plentiful. Moose and black bear are the big game . animals. Smaller animals in the Area are rabbit, mink, · ·. muskrat, beaver, :fox, lynx, marten, land otter, weasel, porcupine, squirrel, marmot, and wolverine. Ducks, geese, ptarmigan, spruce hen, and many other birds are seen in the Area. Many salmon are taken :from the Tan- ana River in midsummer, and there is much fishing :for grayling in tributary streams. . History, Settlement, and Industry Prospectors first entered the Tanana Valley in the 1870's and 1880's, after gold had been discovered in adjoining districts. The search :for gold was intensified after the discovery o:f gold in the Klondike region in 1896. Felix Pedro, a prospector, was the first to discover gold in the Area in 1898. During a return trip to the Area, he persuaded Barnette, captain o:f a small river steamer, to erect a trading post on the Chena River. This is the present site o:f Fairbanks. The town was named :for Sen- ator Charles W. Fairbanks o:f Indiana, who later became Vice President o:f the United States. Another gold strike by Pedro, north o:f Fairbanks in 1902, started a stampede to the Area. By 1904, Fairbanks had over 500 houses and a population o:f about 1,200; the Fairbanks district had a population o:f more than 3,000. In 1910, the population o:f the district had grown to 11,000 persons. As easily accessible deposits o:f gold were ex- hausted, the number o:f people rapidly declined. By 1920, the population was only one-third as large as in 1910. The introduction o:f heavy equipment and efficient mining methods, in the decade :following 1930, made· gold mining a profitable and stable industry. As a result, Fairbanks changed :from a mining camp to a modern city with a steadily growing population. Ladd Air Force Base (now Fort Wainwright), the first permanent military establishment in the Area, was built near Fairbanks in 1939. Since that time, military activity and construction at this base and at nearby Eielson Air Force Base, established a :few years later, have been dom- inant in the local economy. Fairbanks is also the com- mercial and transportation center :for all o:f central and northern Alaska. In the early years, all supplies :for Fairbanks were sent by riverboat :from St. Michael on the Bering Sea or :from Whitehorse in Yukon Territory. In 1913, a wa.gon road was constructed to Fairbanks :from Valdez; on Prmce Wil- liam Sound. Year-round :freight and passenger service to Fairbanks :from Seattle was established in 1923 with the completion o:f the Alaska Railroad. The railroad also J?rovided access to the Healy coalfields, and it was a maJor :factor in the development o:f the modern gold- mining industry. The Alaska Highway, constructed in 1942, connects Fairbanks with Dawson Creek, B.C., and with the roads o:f Canada and the UnitBd States. Roads also extend north :from Fairbanks to the Yukon River and south to Anchorage and Valdez. Commercial airlines connect Fairbanks with Seattle and with all principal points in Alaska. In 1960, the population o:f the city o:f Fairbanks was 13,311; about 38,000 people, excluding military personnel, lived in the greater Fairbanks district. Agriculture The growth o:f agriculture in the Fairbanks Area has always been directly related to the growth o:f nonfarm activities. Agricultural settlement first started during the gold rush in the first decade o:f the 20th century. The principal agricultural products at that time were hay and grain :for horses. Crop production declined as thE population declined after 1910. It increased again after 1918, during construction o:f the Alaska Railroad. By 1920, 107 :farms were in the Area. These :farms had 1,764 acres under cultivation. A flour mill that processed locaJ wheat operated successfully until the completion o:f the railroad. After that, it was cheaper to buy flour shipped :from Seattle. Since the railroad was built, potatoes, veg- etables, and milk have beau the principal :farm products 6 SOIL SURVEY SERIES 1 9 59, NO. 2 5 The demand for local farm products increased sharply after construction of the military bases in 1939, but the breaking of new land for crops was restricted by the high cost of clearing land and of purchasing farm machinery. However, more than 7,000 acres are now cultivated in the Fairbanks Area, and it is expected that 500 to 1,000 acres will be added to this total each year. · The principal crops are bromegrass, oats, peas, barley, potatoes, cabbage, and carrots .. Some wheat and lettuce are grown commercially. Beets, broccoli, cabbage, cauli- flower, celery, carrots, kale, lettuce, onions, peas, radishes, rutabagas, and turnips grow well in the Area. Two small creameries are in the Fairbanks Area, but to satisfy the demand, additional milk and other dairy products must be shipped in. Eggs and some beef and pork are produced in the Area. · How Soils Are Named, Mapped, and Classified Soil scientists made this survey to learn what kinds of soils are in the Fairbanks Area, where they are located, and how they can be used. As they traveled over the area, they observed steepness, l~ngth, and ~hape of slopes; size. and speed of streams; kmds of native plants or crops; kinds of rock; and many facts about the soils. They dug or bored many holes to expose soil profiles. A profile is the sequence of natural layers, or horizons, in a soil; it extends from the surface down to the underlying material that has not been changed much by leaching or by roots of plants. The soil .scientists made comparisons among the pro- files they studied, and they compared these profiles with those in nearby areas and those in places more distant. They classified and named the soils according to uniform procedures. To use this report efficiently l. it is necessary to know the kinds of groupings most used. in a local soil classification. Soils that have profiles almost alike make up a .soil series. Except for different texture in the surface layer, all the soils of one series have major horizons that are similar in thickness, arrangement, and other important characteristics. Each soil series is named for a town or other geogra{>hic feature near the place where a soil of that series was first observed and mapped. Fairbanks and Chena, for example, are the names of two so~l series. All the soils in the United States having the same series name are essentially alike in natural characteristics. Many soil series contain soils that are alike except for texture of their surface layer. According to this differ- ence in texture, separations called soil types are made. Within a series, all the soils having a surface layer of the same texture belong to one soil type. Fairbanks silt loam and Chena very :fine sandy loam are soil types in the Fair- banks and Chena series. Some soil types vary so much in slope, degree of erosion, number and size of stones, or some other feature affecting their use, that practical suggestions about their manage- ment could not be made if they were shown on the soil map as one unit. Such soil types are divided into soil phases. The name of a soil phase indicates a feature that affects management. For example, Fairbanks silt loam~ 3 to 7 percent slopes, is one of several phases of Fairbanks silt loam, a soil type that ranges from nearly level to steep. After a fairly detailed gmde for classifying and nam- ing the soils had been worked out, the soil scientists drew soil boundaries on aerial photographs. They used photos for their base map because these show woodlands, build- ings, field borders, trees, and similar detail that greatly help in drawing boundaries accurately. The soil map in the back of this report was prepared from the aerial photographs. The areas shown on a soil map are called mapping units. The nature of the mapping unit dep~nds on the kind of map prepared. Thethree common kmds of maps are the detailed, reconnaissance, and detailed-reconnaissance. . On a detailed map, the mapping units are precise enough to allow the planning of management for farms and fields. . Such mapping units are nearly equivalent to a soil type or phase of a soil type. They are not exactly equivalent because it is not practical to show, even on a :letailed map, all the small, scattered bits of soil of some other kind that have been seen within an area that is dom- inantly a recagnized soil type or soil phase. On a reconnaissance map, one or more soilJ?hases, types, or even series may be placed in one mappmg unit. A reconnaissance map is not suitable for planning of farms and fields, but it is useful to those who need to appraise the potential of broad areas for agriculture, forestry, or similar uses. On~a detailed-reconnaissance mal?, some of the mapping units are detailed enough for planmng of farms and fields, and some are suitable onlv for judging broader us.es. The map of the Fairbanks Area IS detailed-reconnais- sance. Over most of the Area, the soils were examined and mapped in detail. But along the Chena River, in the eastern part of the Area (see back cover) , the soils were rna pped in less detail, or reconnaissance. In this eastern part of the Area not all the soil boundaries shown on the map were determined, throughout their length by examination. Parts of these boundaries were inferred by observing topographic features. The recmmaissance mapping units in the eastern part of the Fairbanks Area are called soil associations. Th.ese units contain one or more soil types and are readily recog- nized by their names; for example, Goldstream-Lemeta association. In some places in the Fairbanks Area, materials have recently been deposited or exposed and have little plant cover; these materials cannot be called soils, but they are shown on the map like other mapping units. Mapping units consisting of such materials are called miscellaneous land types and are given descriptive names, such as Allu- vial land, Gravel pits, and Mine tailings. Soil Groups According to position on the landscape, the soils of the Fairbanks Area can be placed in two broad geographic groUJ?S: (a) Soils of the uplands, and (b) soils of the alluvial plains (fig. 3). A grouping of this kind brings out relationships among soils not easily made evident in other ways, and it provides a background desirable for study of individual soils. FAIR BANKS AREA, ALASKA 7 ~Uplands ~ Alluvial Plains Figure 3.-Distribution of uplands and alluvial plains in the Fairbanks ~rea. In each of the two broad geographic groups there is a fairly consistent pattern of soils. The soils in the pattern differ from one another in a number of ways, including kind and degree of profile development, degree of wetness, nature of the material from wlnch formed, and depth to underlying bedrock or gravel. Study of figure 4 will dis- close some of the relationships between soil series and position on the landscape, and between soil series and nature of the underlying material and occurrence of permafrost. Soils of the Uplands. All soils of the uplands have de- veloped in micaceous silty material laid down by wind when glacial activity was at its maximum. After deposi- tion, some of this silty material (loess) moved down the slopes of ridges and accmnulated on foot slopes or in nar- row drainageways in the uplands. This process was most pronounced on south-facing slopes, and, as a result, the lower parts of these slopes generally have more gentle gradients than the lower parts of north-facing slopes. The loess covering the bedrock is generally thicker in the low parts than in high parts of the uplands. In the latitude of the Fairbanks Area, south-facing slopes get much more heat from the sun than north-facing slopes. Soil and vegetation reflect this difference in re- ceived heat, especially at the higher elevations in the up- lands. Soils on south-facing slopes have developed under for- ests of white spruce, paper birch, and quaking aspen, and they are generally well drained and free of permafrost. Soils on north-facing slopes have formed under a forest of spindly black spruce and a thick carpet of moss. They are underlain by permafrost and are poorly drained. As a rule, the boundary between soils on north-and south- facing slopes is abrupt at the ridgetops (93). The most extensive soils of the uplands are those of the Fairbanks series. These deep, well-drained, moderately sloping to steep soils are mainly on low hills near the al- luvial plain, and on south-facing middle slopes of high ridges farther from the plains. The shallow, well-drained Gilmore soils are also extensive in the uplands but occur mostly on the higher parts of ridges. The deep, mod- erately well drained Minto soils are dominant on long gentle slopes at the bases of hills below the Fairbanks soils. On north-facing slopes, the Ester soils occupy steep areas near the tops of ridges where the cover of loess is normally thin. The less steep Saulich soils are on the lower slopes that are covered by a thicker mantle of loess. The Goldstream soils occupy sloping upland valleys be- tween ridges. In the uplands, the Fairbanks and Minto soils on gentle to moderate slopes are best suited to agriculture. If given adequate fertilizer and other good management, these soils can produce excellent crops of grasses, small grains, po- tatoes, and other veget~bles. Sloping areas, however, are highly erodible. In addition, some areas of the Minto soils are subject to thermokarst pitting after they have been cleared of vegetation. Soils of north slopes and of upland drainageways are generally too wet for cropping, but the gently to moderately sloping soils in these positions may be productive after the snrface moss has been removed and artificial drainage provided. 8 SOIL SURVEY SERIES 19 59, NO. 2 5 UPLAND ALLUVIAL PLAIN Figure 4.-Diagram of a landscape showing relationship of soil series, underlying material, and permafrost. Adapted from Pewe (7). Soils of the alluvial plains. Soils on alluvial plains have developed in sandy or silty 7. water-deposited material. Most of this soil material is ot glacial origin, but some originated from the loess and underlying bedrock of ad- jacent uplands. Soils near the course of the main streams are generally sandy, and permafrost in them is deep or is absent. Those away from the streams are silty and have a high perma- frost table. Deposits of perennially frozen peat occupy shallow depressions on the alluvial plains. Gravel under- lies all alluvial soils at a depth ranging from less than 1 foot to more than 50 feet. Near the Tanana River, the gravel is mostly rounded pebbles and cobbles laid clown by gla-cial outflow water. In the alluvial plains of the tribu- tary streams, the gravel is mostly angular and subangular fragments of schist or quartzite. The well-drained, sanely Salchaket soils border the principal rivers in the area ancl are the most extensive soils of the alluvial plains. The silty, imperfectly drained Tanana soils ancl the silty, poorly clramecl Goldstream soils occupy large areas between the streams and the up- lands. The poorly drained, sanely Bradway soils, which mainly occupy olcl stream channels and other low areas near the principal rivers, and the Yery poorly drained Lemeta ]Wat, which occupies broad, shallmY depressions, are also fairly extensive on the alluvial plains. The Salchaket and Tanana soils are best suited to agri- culture. Because of their coarse texture, howewr, the Salchaket soils may be droughty in dry years. \Vater perched abo;-e permafrost in the Tanana soils may pre- wnt cropping the first year after clearing, but after that it "·ill not be a serious problem. Many arPas of the Gold- stream alHl Bra<l"·ay soils probably ean he culti,·ated if they are artificially <lrnine<1. Howewr, wetness early in the spring restricts the choice of crops. Lemeta peat is not suitable for cropping. I£ fertilized and properly man- aged, the better soils of the alluvial plains can produce crop yields that are comparable to those obtained from soils of the uplands. Descriptions of the Soils The soils of the Fairbanks Area, Alaska, are described in the following pages. Their acreage and proportionate extent are shown in table 4. Their location can be seen on the detailed map at the end of the report. The soils mapped, their map symbols, and the management group in which each soil has been placed, are listedm the "Guide to :Mapping Units and Management Groups" at the end of the report. The method used in this section is that of first descril->- ing the soil series, and then all the mapping units that be- long to that series. The series are described in alpha- betical sequence. . An important part of each series description is the soil profile, a record of what the soil scientist saw and learned when he dug into the ground. It is to be assumed that all the mapping units of one series haYe essentially the same kind of profile. The differences, if any, are explained in the description of· the mapping unit or are indicated in the name of the mapping unit. The name of each mapping unit is followe<l by a set of symbols in parentheses. These symbols identify the map- ping unit on the detailed soil map. At the end of the de- scription for each mapping unit, the management group for that unit is shown. The management groups are de- scribed in the section "Fse ancl :1Ianagement of the Soils." I • FAIRBANKS AREA, ALASKA 9 Some of the terms used in describing the characteristics of soil series and mapping units, and the significance of these characteristics, are explained in the following paragraphs. The color of a soil can be described in words alone, or by symbols called Munsell color notationsbor by both. In this section, words alone are used to descri e color. In the section "Formation, Classification, and Morphology of the Soils," however, both words and notations are used, since the descriptions of soil profiles in that part are the technical, more detailed kind that scientists need for study and classification of soils. The color of a soil is a clue to its dra.inage. Well-drained soils have brown, yellow, and red colors throughout their profiles. The terms for drainage have specific meaning. A well- drained soil, for example, commonly retains optimum amounts of moisture for plant growth after rains or after irrigation water has been added. Roots can grow deep in such a soil. In contrast, a poorly drained soil is wet most of the time; the water table is at or near the surface a considerable part of the year. The large quantity of water in such a soil prohibits the growing of field crops~ Only moisture-tolerant plants can grow on poorly drained soils. The terms used to describe texture of soils indicate pro- portionate content of sand, silt, and clay. Soils with textures near either extreme, all sand or all clay, are the most difficult to manage; those near midpoint in the tex- tural range, the loam soils, are considered best for most kinds of agriculture. The terms used for structure describe how the incli- vidual soil particles are arranged in larger grains, or aggregates, and indicate the amount of pore space between the grains. In describing structure, separate terms are normally used to indicate strength, or grade, of the aggre- gate; size of the aggregate; and shape of the aggregate. For example, a soil horizon may have "weak, fine, blocky structure." Descriptions of structure help in identifying soils and aid in making inferences concerning their behavior under management. TABLE 4.-Acreage and proportionate ewtent of soils of the Fairbanks Area, Alaska Mapping unit Detailed survey: Alluvial land ____________________________ _ Bradway very fine sandy loam ____________ _ Chena very fine sandy loam ______________ _ Ester silt loam, 12 to 20 percent slopes _____ _ Ester silt loam, 20 to 30 percent slopes _____ _ Ester silt loam, 30 to 45 percent slopes _____ _ Total Ester silt loam ___________________ _ Fairbanks silt loam, 0 to 3 percent slopes ___ _ Fairbanks silt loam, 3 to 7 percent slopes ___ _ Fairbanks silt loam, 7 to 12 percent slopes __ _ Fairbanks silt loam, 12 to 20 percent slopes __ Fairbanks silt loam, 20 to 30 percent slopes __ Fairbanks silt loam, 30 to 45 percent slopes __ Fairbanks silt loam, moderately deep, 3 to 7 percent slopes _________________________ _ Fairbanks silt loam, moderately deep, 7 to 12 percent slopes _________________________ _ Fairbanks silt loam, moderately deep, 12 to 20 percent slopes ______________________ _ Fairbanks silt loam, moderately deep, 20 to 30 percent slopes ______________________ _ Fairbanks silt loam, moderately deep, 30 to 45 percent slopes ____________________ _ Total Fairbanks silt loam _______________ _ Gilmore silt loam, 3 to 7 percent slopes _____ _ Gilmore silt loam, 7 to 12 percent slopes ____ _ Gilmore silt loam, 12 to 20 percent slopes ___ _ Gilmore silt loam, 20 to 30 percent slopes ___ _ Gilmore silt loam, 30 to 45 percent slopes ___ _ Gilmore silt loam, very shallow, 3 to 7 percent slopes ________________________________ _ Gilmore silt loam, very shallow, 7 to 12 per-cent slopes ____________________________ _ Gilmore silt loam, very shallow, 12 to 20 per-cent slopes ____________________________ _ Gilmore silt loam, very shallow, 20 to 30 per-cent slopes ____________________________ _ Gilmore silt loam, very shallow, 30 to 45 per-cent slopes __________________________ _ Total Gilmore silt loam ________________ _ Area Acres 1,356 12, 182 776 773 3,543 3,469 7, 785 175 1, 350 10,660 9, 606 3, 454 600 400 840 2,442 5, 472 676 35, 675 740 1, 257 2, 554 6,856 1, 010 710 160 395 1, 225 992 15, 899 Extent Percent o. 5 4. 8 .3 .3 1.4 1.4 3. 1 . 1 .5 4. 2 3. 8 1.3 .2 .2 .3 1.0 2. 1 .3 14. 0 .3 .5 1.0 2. 7 .4 .3 . 1 . 1 .5 .4 6. 3 Mapping unit Detailed survey-Continued Goldstream silt loam, 0 to 3 percent slopes ___ _ Goldstream silt loam, 3 to 7 percent slopes __ Goldstream silt loam, 7 to 12 percent slopes __ Total Goldstream silt loam _____________ _ Gravel pits _______________________________ 1 Lemetapeat ____________________________ _ Mine tailings ____________________________ _ Minto silt loam, 0 to 3 percent slopes ______ _ Minto silt loam, 3 to 7 percent slopes _______ _ Minto silt loam, 7 to 12 percent slopes _____ _ Total Minto silt loam __________________ _ Salchaket very fine sandy loam ____________ _ Salchaket very fine sandy loam, moderatelyJ deep _________________________________ _ Salchaket very fine sandy loam, shallow ____ _ Total Salchaket very fine sandy loam _____ _ Saulich silt loam, 3 to 7 percent slopes ______ _ Saulich silt loam, 7 to 12 percent slopes ____ _ Saulich silt loam, 12 to 20 percent slopes. __ _ Total Saulich silt loam _________________ _ Tanana silt loam_--------________________ _ Total detailed survey ___________________ _ Reconnaissance survey: Alluvial land __________________ ----------- Ester silt loam, steep ____________________ _ Fairbanks association, moderately sloping to moderately steep ________ ---_--------- Fairbanks-Ester association, steep to very steep _________________________________ _ Gilmore-Ester association, moderately steep_ Area Acres 28, 919 8, 374 330 37, 623 244 3, 074 2, 185 3, 285 16, 420 2, 415 22, 120 40, 736 13, 352. 649 54, 737 2, 700 1, 845 1, 745 6, 290 16, 525 216, 471 680 420 1, 415 4, 990 to very steep _____________ -----___ ------8, 820 Goldstream-Lemeta association _______ -____ -3, 930 Goldstream-Saulich association ____________ -4, 205 Minto-Saulich association_________________ 1, 320 Salchaket association ___ -.-_;-_____________ -~ 8, 340 Tanana-Goldstream assoCiation ___ c __ __ _ _ _ _ 3, 980 Total reconnaissance survey ________ ._____ 38, 100 Total (detailed and reconnaissance survey) _____ j125-!, 571 1 Extent Percent 11. 4 3. 3 . 1 14. 8 . 1 1.2 .9 1.3 6. 4 .9 8. 6 16. 0 5. 2 .2 21. 4 1. 1 .7 .7 2. 5 6. 5 85. 0 '3 .2 .5 2. 0 3. 5 1.5 1.6 .5 3. 3 1.6 15. 0 10::!. 0 1 Does not include 965 acres in urban and industrial uses and 2,167 acrPs of streams and lakes; total extent of the Fairba!lks Area is 257,703 acres. 10 SOIL SURVEY SERIES 1959, NO. 25 Alluvial Land Alluvial land (Ad).-This land type consists of fre- quently flooded areas adjacent to the rivers and sloughs. It is only slightly higher than the normal level of streams, and it is dissected by many small channels. Alluvial land is mainly loose, coarse sand and gravel, but in places it is covered by a thin mantle of gray silty material. It supports a fairly dense cover of shrubs, mosses, sedges, and black spruce. A few isolated areas on higher elevations that support a thick stand of black spruce are included. (Management group 23.) Bradway Series The Bradway series consists of poorly drained sandy soils that occupy former stream channels in the alluvial plain. These old channels range from less than 100 feet to more than a mile in width. The narrow channels wind through many areas of the Salchaket and Tanana soils and generally support a dense stand of sedges and grasses. The broad channels are mainly in the southeastern part of the Fairbanks Area and are covered by low shrubs and clumps of black spruce. Fire has destroyed the trees in many areas of Bradway soils. Typical profile (Bradway very fine sandy loam): 4 inches to 0, black mat of roots, moss, and partially decom- posed organic material mixed with small amounts of silt; medium acid; layer may be as much as 12 inches thick in places. 0 to 2 inches, black, mucky silt loam; weak, granular struc- ture ; friable; slightly acid. 2 to 36 inches +. dark-gray very fine sandy loam mottled with dark brown; weak, platy structure; very friable; mildly alkaline; thin lenses of silt loam and fine sand, mostly below a depth of 24 inches. In many places Bradway soils are greenish or bluish in the lower part. Under the native vegetation, they are perennially frozen below a depth of 3 to 4 feet. Above permafrost, these soils are always wet, except for the upper few inches in some places. In narrow channels near the Tanana and Chena Rivers, these soils are subject to flooding in spring or other times of the year. The Bradway soils are similar to the Salchaket soils in texture but are much more poorly drained because of their lower topographic position. The Bradway soils differ from the Goldstream soils in that they are sandy rather than silty and have a deeper permafrost table. Bradway very fine sandy loam (Br).-This soil is ex- tensive in the alluvial plains of the Tanana and Chena Rivers. In most places, it borders Salchaket very fine sandy loams, but in other places it adjoins Tanana silt loam. A few areas of soil similar to the Goldstream silt loams are included. (Management group 14.) Chena Series The Chena series consists of very shallow, excessively drained sandy soils that have formed in recently deposited material along the Tanana River. These soils are from 3 to 10 inches deep over thick deposits of gravel. They sup- port a forest dominated by white spruce, paper birch, and quaking aspen. Typical profile ( Chena very fine sandy loam) : 2¥.! inches to 0, mat of roots and partially decomposed organic material ; very strongly acid. 0 to 1 inch, very dark grayish-brown and grayish-brown silt loam ; weak, granular structure; friable ; very strongly acid; layer is absent in many places. 1 to 4 inches, dark yellowish-brown very fine sandy loam ; very weak, blocky structure; very friable; medium acid. 4 to 7 inches, grayish-brown fine sand; lighter in color with depth; structureless; loose; slightly acid. 7 to 18 inches +, rounded gravel and coarse sand. Depth to the underlying gravel ranges from 3 to 10 inches. Permafrost is deep or absent. The Chena soils are similar to the Salchaket soils in origin and profile characteristics but are shallower. Because of this shallowness, they are much more droughty than the Salchaket soils. Chena very fine sandy loam (Ch).-This soil occurs only in the southeastern part of the Fairbanks Area. Small areas of the shallow Salchaket very fine Randy loam are commonly included. (Management group 13.) Ester Series The Ester series consists of poorly drained soils with perennially frozen subsoil. The soils have developed in shallow deposits of micaceous silt on north-facing slopes of high ridges. In most places, the Ester soils support a forest of spindly black spruce mixed with scattered alder and willow. A few areas support a stand of paper birch. The surface is generally covered by a thick mat of moss and lichen and a dense growth of low shrubs. Typical profile (Ester silt loam) : 13 to 10 inches, live sphagnum moss. 10 inches to 0, mat of roots and slightly decomposed moss; extremely acid. 0 to 4 inches, very dark grayish-brown silt loam with lenses and po·ckets of black, decomposed organic matter; usually frozen ; very strongly acid. 4 to 10 inches +, olive-gray silt loam with mottles of olive brown and many streaks of dark color ; usually frozen ; strongly acid. Depth to the underlying schist bedrock ranges from less than 10 inches to 24 inches. Where the profile is shallow or where the cover of moss has been removed, the soil may not be frozen in summer. The unfrozen soil is always wet. Near the tops of steep ridges and where slopes change in aspect, the boundary between the Ester and the Gilmore or, less commonly, the Fairbanks soils is abrupt. At ele- vations below the steepest parts of north-facing slopes, the Ester soils generally grade to the deeper Sauhch soils. Small areas of Saulich soils may be included in the map- ping units of Ester soils. Ester silt loam, 12 to 20 percent slopes (EsD).-This soil occurs mostly on moderately steep ridges near upland drainageways. On the lower ·slopes of ridges, it com- monly borders the Saulich silt loams, small areas of which may be included. In most places the Saulich silt loams. are at elevations below this steeper Ester silt loam. (Man- agement group 20.) Ester silt loam, 20 to 30 percent slopes (EsE).-This soil is on steep slopes near the tops of high ridges. Fewer areas of Sauhch silt loams are included with this soil than with Ester silt loam, 12 to 20 percent slopes. (Manage- ment group 20.) ] u d t: n g rr a p th all ho te1 ap of all Tl IS. ar1 va1 slu clu Al, the ( hig ero I Th1 low FAIRBANKS AREA, ALASKA 11 Ester silt loam, 30 to 45 percent slopes (EsF).-This very steep soil is near the tops of high ridges. It differs from Ester silt loam, 20 to 30 percent slopes, only in gradient. (Management group 20.) . Ester silt loam, steep (ERE).-This soil is mapped on the high ridges in the eastern part of the Fairbanks Area. Slopes range from 20 to 45 percent. Small areas of Saulich silt loams are included. This soil is shallow, should not be cleared of vegetation, and is not suitable for cultivation. "The sedges and grasses can be grazed, but forage ,yields are low. · Fairbanks Series The Fairbanks series consists of well-drained soils of the uplands that have developed in moderately deep to deep deposits of micaceous silt. These soils occur mainly near the middle of long, south~facing slopes and on low hills near the alluvial plains. Fairbanks soils can support good stands of white spruce and paper birch. However, many areas of these soils have been burned or cut over and are now covered by young stands of aspen and, in places, alder. Typical profile (Fairbanks silt loam) : 2 inches to 0, dark reddish-brown mat of partially decom- posed organic material~ many roots; slightly acid. 0 to 4 inches, dark-brown silt loam; very weak, crumb struc- ture; very friable; slightly acid. 4 to 7 inches, brown to yellowish-brown silt loam; moderate, very thin, platy structure breaking easily to very fine, gran- ular structure ; very friable; strongly acid. 7 to 12 inches, dark-brown silt loam that contains thin, roughly horizontal bands of dark yellowish-brown, heavy silt loam or silty clay loam; moderate, very thin, platy struc- ture; very friable ; strongly acid. 12 to 16 inches, dark yellowish-brown silt loam; moderate, very thin, platy structure; very friable ; strongly acid. 16 to 26 inches, olive silt streaked with dark brown; moder- ate, very thin, platy structure; very friable; medium acid. 26 inches +, olive silt; moderate, very thin, platy structure; very friable; slightly acid. · The thin bands of heavy silt loam or silty clay loam in the 7-to 12-inch layer range from less than % inch to almost % inch in thickness. These bands are roughly horizontal, but they fork and merge in an irregular pat- tern. They occur immediately below the surface soil and apparently are the result of soil development rather than of deposition. Near the bases of slopes, the Fairbanks soils are gener- ally bordered by the moderately well drained Minto soils. The boundary between soils of these two series generally is gradual, and patches of Minto soils may be included in areas mapped as the Fairbanks soils. At the higher ele- vations on steep slopes, the Fairbanks soils grade to shallower Gilmore soils. Gilmore soils are commonly in- cluded with the Fairbanks soils on the higher slopes. Along very narrow drainageways, strips of soil similar to the Minto soils may occur within areas of Fairbanks soils. Cleared areas of the more sloping Fairbanks soils are highly susceptible to sheet and gully erosion. Control of erosion is essential in managing these soils. Fairbanks silt loam, 0 to 3 percent slopes (FaA).- The few areas of this nearly level soil are at the tops of low ridges or hills. These areas are generally very gently undulating rather than flat. There are few or no inclu- sions of other soils. (Management group 2.) Fairbanks silt loam, 3 to 7 percent slopes (FaB).- N early all areas of this gentlY. sloping soil are on or near the tops of low ridges or hills. Most of them are not extensive. They differ from Fairbanks silt loam, 0 to 3 percent slopes, only iin gradient. (Management group 4.) Fairbanks silt loam, 7 to 12 percent slopes (FaC).- This moderately sloping soil occurs on the middle and lower parts of long, concave, south-facing slopes; on slopes of low hills riear the flood plains; and on the tops of low ridges. At ~ts lower boundary, this soil commonly grades to the Minto soils; at the upper boundary, it grades to the steeper members of its own series. Patches of these borderi.J:ig soils are included. As a rule, the slopes of Fairbari.ks silt loam, 7 to 12 percent slopes, are fairly smooth, but in places they are dissected by minor drainageways. Narrow strips of the Minto soils, too small to delineate separately, occupy these dissected areas. (Management group 7.) Fairbanks silt loam, 12 to 20 percent slopes (FaD).- This moderately steep soil occupies topographic positions that are sirnjlar to those occupied by Fairbanks silt loam, 7 to .12 percent slopes. It Is much more dissected by minor drainageways and includes more strips of the Minto soils. Patches of the moderately deep Fairbanks silt loams have also been included, especially higher on the slopes. (Management group 12.) Fairbanks silt loam, 20 to 30 percent slopes (FoE).-· This steep soil generally is on the higher parts of long, south-facmg slopes. Here the thickness of silt over bed- rock is normally not as great as on lower slopes. Patches of the moderately deep Fairbanks silt loams are commonly included. Minor dramageways and strips of Minto soils are less numerous than in the moderately steep Fairbanks soils. (Management group 16.) Fairbanks silt loam, 30 to 45 percent slopes (FaF).- This very steep soil differs from Fairbanks silt loam, 20 to 30 percent slopes, only in steepness of slope. Patches of Minto soils are rarely included. (Management group 19.) . Fairbanks silt loam, moderately deep, 3 to 7 percent slopes (FmB).-This moderately deep soil has formed in a silty deposit that is 20 to 36 inches thick over bedrock. This soil occurs in only a few places, mostly on ridge- tops. These areas are on higher elevations than those of the gently sloping, deep Fmrbanks silt loams. Patches of Gilmore silt loams are included in places. (Manage- ment group 4.) Fairbanks silt loam, moderately deep, 7 to 12 percent slopes (FmC).-This moderately sloping soil occupies posi- tions that are similar to those occupied by Fairbanks silt loam, moderately deep, 3 to 7 percent slopes. It differs only in gradient. (Management group 7.) Fairbanks silt loam, moderately deep, 12 to 20 per- cent slopes (FmD).-This soil occurs mostly on the higher parts of ridges. Except for the thickness ( 20 to 36 inches) of the silty deposit in which this soil has developed, it is like Fairbanks silt loam, 12 to 20 percent slopes. The a1•eas of Fairbanks silt loam, moderately deep, 12 to 20 percent slopes, are only slightly dissected by minor drainagmvays, and very few patches of the Minto soils are 12 SOIL SURVEY SERIES 19 59, NO. 2 5 included. Small areas of the Gilmore silt loams and the deep Fairbanks silt loams are commonly included. (:Man- agement group 12.) Fairbanks silt loam, moderately deep, 20 to 30 per- cent slopes (FmE).-This steep soil occurs on the slopes of high ridges in the northern part of the Fairbanks Area. Except for depth to bedrock, it is similar to Fairbanks silt loam, 20 to 30 percent slopes. Included are small patches of steep Fairbanks silt loams and of Gilmore silt loams. (Management group 16.) Fairbanks silt loam, moderately deep, 30 to 45 per- cent slopes (FmF).-This very sreep soil differs from Fair- banks silt loam, moderately deep, 20 to 30 percent slopes, mainly. in gradient. In addition, included patches of Gil- more silt loams are somewhat more numerous, and there are a few outcrops of rock. (Management group 19.) Fairban]{S association, moderately sloping to moder- ately steep (FBD).:;.:-This mapping unit is in the eastern part of the Fairbanks Area. Soils in this part were mapped in less detail than in the western part of the Area. The deep and moderately deep Fairbanks soils on southerly slopes of high ridges were mapped as a unit. More than three-fourths of this unit has slopes of 12 and 20 percent; about half of this area consists of the deep Fairbanks silt loams. Inclusions of other soils are like those i'l.escribed for the Fairbanks soils. W'"hen these soils are cleared of trees, the risk of erosion is severe. Cleared areas should be kept more than half the time in hay meadow, or in pasture if grazing is con- trolled. Small grains or row crops should be grown in strips. Diversion ditches and grassed waterways should be built. to dispose of excess water safely. Fairbanks-Ester association, steep to very steep (FEF).-This mapping unit is on high ridges in the eastern part of the Fairbanks Area. In this part, the soils on southerly and northerly slopes were mapped as one unit. Fairbanks silt loams, mostly moderately deep, make up more than 75 percent of this mapping unit. As in other parts of the Area, Ester silt loams are on north-facing slopes. Also included in this mapping unit are many areas of Gilmore silt loams on southerly slopes and of Goldstream silt loams along small streams. The soils in this mapping unit should be left in forest. Gilmore Series The Gilmore series consists of well-drained soils of up- ·-htnds. The soils have developed in shallow to very shal- low deposits of micaceous silt. They occur on south- facing slppes of high r1dges in the northern part of the Fairbanks Area. Marketable stands of white. spruce, aspen, and paper birch are available, but most areas of Gilmore soils have been burned over or cut over. Present stands consist mainly of quaking aspen and, in places, alder. Typical profile (Gilmore silt loam) : 4 inches to 0, mat of moss and other organic material; partially decomposed in the upper part but well decomposed in the lower part; medium to slightly acid. 0 to 2 inches, very dark grayish-brown silt loam ; very weak, very thin, platy structure; very friable; strongly acid. 2 to 5 inches, brown silt loam with a few angular pebbles; weak, very thin, platy structure; very friable; strongly acid. 5 to 8 inches, dark-brown silt loam with a few angular pebbles; moderate, very thin, platy structure; very friable; thin, un- dulating band of heavy silt loam or silty clay loam near bot- tom of layer ; strongly acid. 8 to 17 inches, dark grayish-brown silt loam with a few angular pebbles; moderate, very thin, platy structure; very friable; very thin, irregular band of heavy silt loam or silty clay loam in middle of layer ; strongly acid. 17 to 24 inches+, weathered mica schist. Depth to the underlying rock ranges from 6 to 20 inches. In soils that have developed in thin silty deposits, the brown subsoil may extend into the schist, and the undulat- ing bands of finer material may be absent. At high eleva- tions, a gray or grayish-brown layer may be near the surface. In many places, the mat of organic material on the surface has been partially or wholly destroyed by fire. The Gilmore soils have developed in much the same way as the Fairbanks soils but differ from them in their shal- lowness to bedrock and in the absence of a layer of un- weathered silty material beneath the brown soil material. In general, the Gilmore soils grade downslope to the Fair- banks soils. Like the Fairbanks soils, the Gilmore soils are highly susceptible to erosion after clearing. Gilmore silt loam, 3 to 7 percent slopes (GmB).-This gently sloping soil occurs principally on the tops of high, narrow ridges. The silty mantle over the bedrock is nor- mally 10 to 20 inches thick. Areas mapped as this soil may include patches of Fairbanks silt loams, moderately deep, and of Gilmore silt loams, very shallow. (Manage- ment group 10.) Gilmore silt loam, 7 to 12 percent slopes (GmC).-This soil is mainly on high ridges. It differs from Gilmore silt loam, 3 to 7 percent slopes, only in gradient. (Man- agement group 13.) Gilmore ~ilt loam, 12 to 20 percent slopes (GmD)~­ This moderately steep soil is mainly on high ridges. Down the slope it grades to the moderately deep Fair- banks silt loams, and up the slope, it may grade to the steeper, very shallow Gilmore silt loams. Patches of both these soil types may be included. As a rule, the slopes of Gilmore silt loam, 12 to 20 percent slopes, are fairly smooth, but they are dissected in a few places by shallow drainageways. (Management group 17.) . Gilmore silt loam, 20 to 30 percent slopes (GmEj.-This steep soil is mostly near the tops of high ridges. It con- tains fewer inclusions of the moderately deep Fairbanks silt loams than of the moderately steep Gilmore silt loams. However, patches of very shallow Gilmore silt loams are more numerous. In these patches there are a few outcrops of rock. (Management group 19.) Gilmore silt loam, 30 to 45 percent slopes (GmF).-This very steep soil is similar to Gilmore silt loam, 20 to 30 percent slopes, except that it has steeper slopes and occu- pies higher positions on the ridges. In addition, the patches of the very shallow Gilmore silt loams and of rock outcrops are somewhat more numerous. (Management group 19.) Gilmore silt loam, very shallow, 3 to 7 percent slopes (GrB).-This soil has formed in a deposit of micaceous loess that is less than 10 inches thick over bedrock. In most places, the soil-forming processes have modified a few inches of the underlying rock. The content of clay in this weathered bedrock is slightly higher than in weathered bedrock elsewhere in the Fairbanks Area. Gilmore silt loam, very· shallow, 3 to 7 percent slopes, p t fl a. tl ,, FAIRBANKS AREA, ALASKA 13 occurs on gentle slopes on a few high ridgetops. Patch~ of the deeper Gilmore silt loams may be included with this soil. (Management group 13.) Gilmore silt loam, very shallow, 7 to 12 percent slopes (GrC).-Except for slopes,· this soil is like Gilmore silt loam, very shallow, :3 to~ J?ercent slopes, and it occurs in the same topographic positiOn. (Management group 17.) Gilmore silt loam, very shallow, 12 to 20 percent slopes (GrD).-This soil occurs on the slopes and tops of high ridges. Rock outcrops are more numerous than in the gently sloping, very shallow Gilmore silt loams. A few patches of the deeper Gilmore silt loams have been included. (Management group 17.) Gilmore silt loam, very shallow, 20 to 30 percent slopes (GrE).-This steep soil generally is on the high parts of ridges. Rock outcrops are fairly common on these steep slopes, but in general, the slopes are smooth and only slightly dissected. · A few patches of the deeper Gilmore silt loams are included. (Management group 19.) Gilmore silt loam, very shallow, 30 to 45 percent slopes (GrF).-Except for gradient, this very steep soil is like Gilmore silt loam, very shallow, 20 to 30 pe-rcent slopes. (Management group 19.) Gilmore-Ester association, moderately steep to very steep (GEF).-This mapping unit is in the eastern part of the Fairbanks Area, where the shallow soils on high ridges were mapped as a unit. Gilmore silt loam, 30 to 45 per- cent slopes, makes up more than half the area. of these soils, and Gilmore silt loam, 20 to 30 percent slopes, makes up most of the rest. Ester silt loam, which is on north- facing slopes, covers about 20 percent of the mapping unit. Areas of the very shallow Gilmore silt loams are common. Patches of the moderately dee~ Fairbanks silt loams also occur. The soils in this association should be kept in forest. Goldstream Series The Goldstream series consists of poorly drained silty soils with perennially frozen subsoil. These soils occur in broad, low areas of the alluvial plain. along principal rivers and in relatively narrow strips along upland dram- ageways. The native vegetrution is a dense growth of shrubs and a few clumps of spindly black spruce, tama- rack, and willow. Numerous cl0sely spaced tussocks of sedge, some as much as 18 inches high and 12 inches-wide, give the soil surface a hummocky appearance. Between the tussocks, the soil is covered by moss. . Typical profile (Goldstream silt loam) : 5 inches to 0, mat of moss and roots ; upper ))art of moss is Jndecomposed, but the lower ))art is black and finely divided; strongly acid. 0 to 4 inches, black silt loam ; weak, fine, blocky structure; slightly sticky when wet; strongly acid. 4 to 19 inches, gray silt loam; many mottles of olive brown and few irregular streaks of black ; massive; sticky; neutral; frozen below depth of 19 inches late in summer. Lenses of fine sand may occur in the lower part of the profile, especially in soils on the broad alluvial plain. Under native vegetation, the depth to permafrost ranges from 10 to about 24 inches. The soil above permafrost is always semifluid. The Goldstream soils occur in slightly lower areas of the alluvial plain than the Tanana soils, and they are more poorly drained and tiner textured. The Goldstream soils are finer textured than the sandy Bradway soils, which are also in low areas on the alluvial plain. The_y are generally somewhat wetter than the poorly drained Saulich soils on north-facing slopes bordering upland drainageways. Goldstream silt loam, 0 to 3 percent slopes (GtA).- This nearly level soil occurs mostly on alluvial plains of the Tanana and Chena Rivers and Goldstream Creek, and along the lower parts of the main tributaries of these streams. Layers of sand and sandy loam in the subsoil are more common in this soil than in Goldstream silt loams in: upland drainageways. Included are· patches of soil that resemble Tanana silt loam. Lemeta peat occurs in depressions too small to map separately. (Management group 14.) Goldstream silt loam, 3 to 7 percent slopes (GtB).- This gently sloping soil occurs in fairly narrow strips in upland drainageways and at the bases of hills that border the alluvial plain. It has formed mainly in silty material that washed from adjoining slopes. This silty material is many feet thick and contains almost no lenses of sand. Because many black organic streaks occur in the profile, even !l.t great depths, the soil is known locally as muck. Trees grow mainly on very narrow strips of sandy soils along small streams flowing through the centers of some areas. These included sandy soils resemble those of the Salchaket series. (Management group 15.) Goldstream silt loam, 7 to 12 percent slopes (GtC).- Except for slopes, this soil is like Goldstream silt loam, 3 to 7 percent slopes. (Management group 15.) Goldstream-Lemeta association (Gl).-This mapping unit occupies nearly level, low areas on the alluvial plain of the Chena River in the eastern part of the Fairbanks Area. It consists of Goldstream silt loam and Lemeta peat that were mapped together in a reconnaissance survey. Goldstream silt loams comprise about 80 percent of the mapping unit; Lemeta pea~ is in shallow depressions sur- rounded ~by Goldstream .silt loa~s. ~mall I?at~hes of Tanana silt loam are also mcluded m this assocmbon. These poorly drained soils are underlain by permafrost. Open ditches are needed to remove excess moisture from cleared fields of Gold,stream silt loams. Even if drained, these soils dry out slowly in spring. As a result, planting dates are late, and only short-season crops, such as grains, grasws, and some vegetables, can be grown. Lemeta peat will not be productive, even if it is drained. Goldstream-Saulich association (GS).-This mapping unit is in the eastern P.art of the Fairbanks Area. It con- sists of Goldstream silt loams on flood plains and Saulich silt loams on foot slopes adjacent to tributaries of the Chena River. Slopes are mainly 3 to 7 percent, but there are also nearly level areas and slopes as steep as 12 percent ~n this m!Lpping unit. Gol4stream silt loams are the d?m- mant soils. On south-facmg slopes, patches of Mmto silt loams are included in the association. The soils in this association are poorly drained and need open ditches to remove excess water if they are to be cul- tivated. Tilth can be maintained in most fields by occa- sionally adding organic matter and by avoiding tillage when the soil is wet. Fertilizer should be applied accord- ing to needs determined by soil tests. Some areas are in low places for which suitable drainage outlets are not available. These areas cannot be drained successfully. 14 SOIL SURVEY SERIES 1 9 59, NO. 2 5 Even if drained, the soils of this association dry out slowly and only short-season crops can be grown. Grasses, some vegetables, and grains are most suitable. Grasses should not be grown more than 4 years in ,succession, be- cause they produce an insulating eff€ct that encourages the return of permafrost. Gravel Pits Gravel pits (Gv).-This is a land type that occurs on the alluvial plain and, less commonly, along roads in the uplands. On the alluvial plain, Gravel pits are generally surrounded by Salchaket or Tanana soils, and in the up- lands by the Gilmore or the moderately deep Fairbanks ~oils.' Most Gravel pits on the alluvial plain have been excavated to a depth of several feet below the water table. (Management group 22.) Lemeta Series The Lemeta series consists of peat soils that have formed in depressions in the alluvial plain. The peat consists mostly of undecomposed sphagnum moss, but it also con- tains layers of slightly decomposed sedge. The lower part of the peat and the underlying mineral soil are per- enially frozen. In addition to mosses and sedges, Lemeta peat supports a dense growth of shrubs and clumps of spindly black spruce, tamarack, and other trees. Tus- socks of sedge are common, especially near the edges of the peat bogs. · Typical profile (Lemeta peat) : 0 to 13 inches, dark-brown (when moist) moss peat arranged in thin horizontal layers ; light brown when squeezed dry ; few, thin layers of black sedge peat; strongly acid. 13 to 25 inches, moss peat similar to that in 0-to 13-inch layer, but with many layers of black sedge peat; very strongly acid ; frozen below depth of 25 inches. Woody par~icles may occur at any depth in the peat. Free water occurs immediately below the surface through- out the summer. Depth to permafrost ranges from 1 foot to about 2lf2 feet. Lemeta peat (lp).-This soil is generally surrounded by broad areas of Goldstream silt loams and may include patches of those soils near its boundary. Ponds, or small lakes, are common in the peat bogs. Some lakes, or ponds, are open, but others are filled with sedge and horsetail. (Management group 21.) Mine. Tailings Mine tailings (Me).-This is a land type that consists of mounds of coarse rubble left by gold dredges in several of the tributary valleys of the Tanana River and Gold- stream Creek. The silty overburden above the gold- bearing gravel was usually many feet thick. This was removed hydraulically before dredging operations started. (~fanagement group 22.) Minto Series The Minto series consists of nearly level to moderately sloping, moderately well drained soils that have developed in micaceous silty material. This material is many feet thick oYer bedrock. The Minto soils occupy the bases of hills that are dominated by the well-drained Fairbanks soils. In most places, . they support forests of white spruce, paper birch, and quaking aspen, like those on the Fairbanks soils, but some areas are covered by black spruce. The forest floor is generally covered by n:toss, grass, and horsetail. Typical profile (Minto silt loam) : ) 4 inches to 0, mat of roots, moss, and partially decomposed organic material; extremely acid. 0 to 3 inches, very dark grayish-brown silt loam ; weak, fine, granular structure; friable; very1strongly acid. 3 to 7 inches, dark grayishcbrown silt loam with dark yellow- ish-brown mottles and dark streaks ; weak, blocky structure breaking to very thin, platy ; very friable ; strongly acid. 7 to 15 inches, dark grayish-brown silt loam mottled with fain,t olive brown ; moderate, very thin, platy structure ; very fri- able ; slightly acid. 15 to 30 inches +, dark grayish-brown silt that contains many horizontal streaks of olive brown ; moderate, very thin, platy structure; very friable; mildly alkaline. The Minto soils differ from the Fairbanks soils in having grayish rather than brown or yello.wish-brown .su~soil, in lacking the thin bands of fine material charactenstiC of the Fairbanks soils, and in having mottles throughout the pro- file. The Minto soils are not so highly mottled as the im- perfectly drained Tanana soils of the river flood plains, and they are br<;>wner. . . . The Minto soils grade to the Fairbanks soils on higher slopes, and to the Tanana or the Goldstream soils on the bordering flood plains: Inclusions of small p~tches . of these soils are common m areas mapped as the Mmto soils. Many areas of Minto soils are underlain at a depth of 6 feet or more by irregular, discontinuous masses of ice. After clearing of vegetation and subsequent warming of the soil, this ice may melt. Soil subsidence resulting from the melting of ice and tunneling in the subsurface may re- sult in the formation of deep, steep-walled pits or in a very hummocky microrelief. These conditions may be- come severe enough in fields to prevent their further agri- cultural use ( 7). Cleared areas of the sloping Minto soils are subject to sheet and gully erosion. Minto silt loam, 0 to 3 percent slopes (MnA).-This nearly level soil occurs at the bases of long, concave upland slopes that have a southerly exposure. Small patches of Tanana silt loam, and of Goldstream silt loams, which are soils of the flood plains, may be included with this Minto . soil. Minto silt loam, 0 to 3 percent slopes, is somewhat more highly mottled than the Minto soils on higher areas. Under natural. conditions, this soil generally has a thicker coverofmoss. (Managementgroup3.) Minto silt loam, 3 to 7 percent slopes (MnB).-This soil occupies the lower parts of long, southerly upland slopes and a few low, isolated hills adjacent to flood plains. On hillsides, there is a gradual boundary between this soil and the higher lying, steeper Fairbanks silt loams. Con- sequently, near the boundary, patches of Fairbanks silt loams are included with this soil. In addition, narrow strips of the Goldstream soils, which occur along some of the minor drainageways, have been included. (Manage- ment group 5.) . Minto silt loam, 7 to 12 percent slopes (MnC).-This moderately sloping soil is mostly on low hills near the river flood plains. Some of the slopes face north, and on these, a few areas resembling the Saulich silt loams are 1 Cl Cl Sl f« tl tl li n« 0' pl cl cl d1 fo ~~ (1 ,j ·! ~·if: J I FAIRBANKS AREA, ALASKA 15 included. On the south-facing slopes, patches of Fair- banks silt loams are included. In the minor drainageways on all slopes, narrow strips of Goldstream silt loams were mapped with Minto silt loam, 7 to 12 percent slopes. (Management group 8.) Minto-Saulich association (MS).-This association was mapped on the foot slopes of hills in the eastern part of the Fairbanks Area. The gently sloping to moderately sloping Minto silt loams are dominant in this association. They occur mostly on south-facing slopes having a gradient in the range of 3 to 12 _percent. Saulich silt loams are on north-facing slopes. Small areas of Goldstream silt loams that occur along drainageways are included in the association. If cleared of vegetation, these soils are subject to sub- sidence because of the melting of subsurface ic~. This causes uneven settling and pitting of the surface and may make cultivation difficult or impossible. In addition, these soils are subject to severe erosion and should be cultivated only_ if adequate precaution is taken to control accelerated erosiOn. Salchaket Series The Salchaket series consists of nearly level, well- drained soils that have· developed in recently deposited water-laid material along the Tanana and Chena Rivers. These soils are dominantly sandy but commonly contain layers of silty material. They are underlain by thick de- posits of coarse sand and gravel. The Salchaket soils support a forest of white spruce, paper birch, and quaking. aspen. Near streams, these forests contain some balsam poplar. Most forested areas have been burned or cut over, and many areas have been cleared for farming and homesites. · Typical profile (Salchaket very fine sandy loam) : 7 inches to 0, mat of roots, moss, and partially decomposed organic material; very strongly acid. 0 to 3 inches, olive-brown and grayish-brown silt loam with black lenses of decomposed organic matter; weak, granular structure; very friable; very strongly acid. 3 to 10 inches, gray and brown very fine sandy loam with few black lenses ; very weak, blocky structure ; very friable; slightly acid. 10 to 26 inches, gray fine sand wfth mottles of strong brown ; structureless ; loose; mildly alkaline. 26 inches +, gravel and coarse sand; all pebbles are rounded. Depth to the gravelly underlying material ranges from 10 inches to 6 feet or more. Thin silty lenses or seams of coarse sand may occur at any depth m the profile, espe- cially in areas far from the present river courses. The silty surface layer is absent in some places, but in a few places it may be more than 12 inches thick. As a rule, the soil above gravel is not perennially frozen, but under the native vegetation, ·silty lenses may stay frozen well into the summer. Salchaket very fine sandy loam (Sc).-This level to nearly level soil is generally more than 36 inches deep over the underlying gravel. The surface is dissected in places by sloughs and by the scars of old streams. In- cluded are many small areas of the moderately deep Sal- chaket very fine sandy loam and strips of the poorly drained Bradway very fine sandy loam, which occupy former sloughs that are too narrow to delineate separately. (Management group 1.) Salchaket very fine sandy loam, moderately deep (Sm).-This soil is 20 to 36 inches deep over gravel. Small areas may be thicker or thinner, because of the var- iations in the depth to underlying gravel. As a rule, this moderately deep soil'has fewer silty lenses than Salchaket very fine sandy loam, and there are fewer strips of Brad- way very fine sandy loam included. (Management group 6.) Salchaket very fine sandy loam, shallow (Ss).-This soil is generally 10 to 20 inches thick over gravel. It is shallower than Salchaket very fine sandy loam, moder- ately deep, but otherwise is like it. Many patches of the moderately deep Salchaket very fine sandy loam and a few of the even shallower Chena soils are included. (Management group 9.) Salchaket association (SA).-This association was mapped along the Chena River in the eastern part of the Fairbanks Area. It consists of the deep and moderately deep Salchaket very fine sandy loams. Most of the soil in this association is thicker than 36 inches, but the depth to the underlying gravel varies considerably. Included with this mapping unit are patches of the shal- low Salchaket soils, and in former stream channels, strips of the poorly drained Bradway very fine sandy loam. These soils warm up and can be worked earlier in the season than the silty soils of the Area. Droughtiness may reduce yields, but crops will respond to supplemental irri- gation. Cro:ps that are suited to the climate will produce good yields If seeded early and fertilized ·.according to needs determined by soil tests. Crop residue or manure should be a_pplied regularly to maintain tilth and soil structure. Serious erosion hazards do not exist on these nearly level soils. Saulich Series The Saulich series consists of poorly drained soils that occupy mainly the lower parts of north-facing slopes. The soils have developed in fairly thick deposits of silty material. The subsoil is perennially frozen. The soil surface is covered by a thick mat of moss and a dense growth of low shrubs. In most places the Saulich soils support a sparse stand of spindly black spruce, mixed with scattered alders and willows. Typical profile (Saulich silt loam) : 7 inches to 0, rna t of roots and moss ; extremely acid. 0 to 4 inches, dark olive-gray silt loam streaked with black; very weak, platy structure; very friable ·when moist, non- sticky when wet; very strongly acid. 4 to 7 inches, dark grayish-brown and very dark grayish-brown silt loam with a few, thin streaks of black; weak, platy structure; very friable when moist, nonsticky when wet; strongly acid. 7 to 15 inches +. dark grayish-brown silt loam with many mottles of olive brown and a few streaks of black; weak, platy structure; very friable when moist, nonsticky when wet; frozen below a depth of 15 inches; medium acid. Depth to permafrost ranges from 12 to 30 inches, but it · may be more where the natural cover of moss has been removed. In their }\atural condition, these soils are always saturated above the permafrost. At the higher elevations on the slope, the Saulich soils generally border the steeper, shallow, and poorly drained Ester soils; at lower elevations on the slope, adjacent to 16 SOIL SURVEY SERIES 1 9 59, NO. 2 5 upland drainageways, they border the more gently slop- ing Goldstream soils. · Areas of Saulich soils may include patches of either of these two soils. Saulich silt loam, 3 to 7-percent slopes (SuB].-This gently sloping soil is on north-facing slopes in positions that are comparable to those the Minto soils occupy on southerly slopes. At lower elevations on the slope, this soil grades to areas of Goldstream silt loams, patches of which maybe included. (Management group 15.) Saulich silt loam, 7 to 12 percent slopes (SuC].-This soil is on the middle and low parts of north-facing slopes. These slopes are generally smooth and undissected. At lower elevations along the drainageways, this soil grades to areas of Goldstream silt loams. Up the slope, it may border Ester silt loams. A few J;>atches. of either of these soils may be included with this soil. (Management group 15.) Saulich silt loam, 12 to 20 percent slopes (SuD].-This soil is on the middle slopes of high ridges. It commonly borders the steep Ester silt loams higher on the slope and the more gently sloping Saulich silt loams lower on the slope. Saulich silt .loam, 12 to 20 percent slopes, has de- veloped in so:rnewhat thinner deposits of silty material than the more gently sloping Saulich silt loams. Small areas of Ester Silt loams are commonly included. (Man- agement group 18.) . Tanana Series The Tanana series consists of nearly level, imperfectly drained soils that have developed in silty materials on alluvial plains. These soils occur farther from the prin- cipal streams than the Salchaket soils and in slightly higher pQsitions than the Goldstream soils. In many places, the Tanana soils border the Minto soils on the foot slopes of uplands. The Tanana soils support a scrubby forest of black and white spruce, paper birch, tamarack, and willow. A fairly smooth mat of mosses and low shrubs generally covers the surface. Under the native vegetation, the soil is peren- nially frozen at a depth of 30 inches or less. Afterthe mat of moss has been cleared, the depth to permafrost gen- erally increases to more than 6 feet. When this occurs, excess moisture can percolate through the soil. Typical profile (Tanana ~ilt loam): 5 inches to 0, :inat of roots, m:oss, and lichen; color grades from dark brown at surface to black.at bottom of horizon~ strongly acid. · -0 to 4 inches, olive-gray silt loam with many streaks and patches of black and grayish brown; massive; friable; neutral. _ 4 to 20 inches, olive-brown silt loam with streaks and patches of black and grayish brown and mottles of dark brown ; massive; friable ; mildly alkaline; perennially frozen below depth of 20 inches under native vegetation. Lenses of very fine sandy loam or fine sand are common. Gravel underlies most areas at a depth of 4 to 10 feet .. Tanana silt loam (Ta).-This nearly level soil is exten- sive on the alluvial plains. Near the uplands, it grades· to the moderately well drained Minto silt loams. Else- where on the plains, it borders the well-drained Salchaket very fine sandy loams or the poorly drained Goldstream silt loams and the Bradway very fine sandy loam. In- cluded with this soil are many small patches of Minto and Goldstream silt loams. These included areas' occur most often where this soil borders the Minto .or Goldstream soils. Bradway very fine sandy loam has been included. where it occu.r.ies winding, narrow channels within areas of Tanana silt loam. Small areas of · Salchaket very fine sandy loams and Lemeta peat are also included but are rare. (Management group 11.) Tanana-Goldstream association (TG].-This associa- tion was mapped in the eastern part of the Fairbanks Area, along the Chena River. Tanana silt loam is the dominant soil, but Goldstream silt loams occupy large areas in slightly lower positions. Inclusions of other soils of the _alluvial plains, as described for Tanana silt loam, are common. These soils are almost always wet before clearing because· the ground water perched above the permafrost cannot escape. After the vegetation and ground cover of moss have been cleared, the soil will be dry enough to cultivate in 1 or 2 years without the need of artificial drainage. Shallow ditches are needed in some fields to carry off excess moisture in the spring. The removal of excess water allows earlier seedmg and reduces the chances of frost damage to crops late in summer. All crops that are suited to local conditions can be grown but require fertilizer in quantities determined by soil tests. Crop residue and manure should be applied to maintain tilth and soil structure. Grasses should be grown. part of the time in the cropping systems. · Use and Management of the Soils This section consists of three parts. The first discusses methods of clearing vegetation from land intended for farming; the second discusses crop yields and fertilization in the Area; and the third explains how soils are grouped for management. Clearing Land The well drained and moderately well drained soils can be cleared any time after the marketable trees have been harvested. However, clearing is most efficiently done when the soil is not frozen. The underbrush and trees left after logging are pushed over by a bulldozer equipped with a scarifier blade. This material, together with large roots, is then pushed into windrows. If clearing is done on frozen ground, trees are sheared off above the ground and moved into windrows. They are allowed to dry and are then burned. Large roots and stumps are later moved to the windrows with a scarifier blade or a heavy breaking plow. On sloping land, windrows should be made diagonally across the slopes to keep runoff from ponding on the upper sides and,,·at the same t~e, to control runoff from newly cleared soil. Natural dramageways should not be blocked. Windrowed material should be allowed to dry and then burned. Precautions must be taken to prevent' the spread of fire to surround,_ing forests. In most well-drained soils, the organic material is concentrated in a mat at the soil surface. This mat should not be removed in clearing. The imperfectly drained and poorly drained soils are generally underlain by permafrost, and the removal of most of th~ surf~e mat of organic matter is necessary. Most of this mat IS undecomposed moss or sedge, and if -·~ I FAIRBANKS AREA, ALASKA 17 it is not removed, it will prevent the soil from drying and reduce the effectiveness of some fertilizers. Some of the organic matter, however, should be left as an aiel to good tilth. The excess moss should be turned up by using an angle blade or a comparable implement. After the moss has dried, it should be burned in place. It should not be piled in windrows, as it dries slowly and will be very difficult to burn. The moss not turned up will stay wet for at least a year, so there is little danger of complete loss of organic matter. The tussocks of sedge on wet soils are most easily sheared off when the soil is frozen. They can be burned with the excess moss. On alluvial plains the clearing of the imperfectly drained and poorly drained soils should start next to a stream or other natural drainage,Yay. On slopes, how- ever, it should start at the upper end and progress clown the hill. In both situations, small pockets should not be cleared in undisturbed areas, as runoff and water from melting ice will collect in the cleared pockets and prevent the soil from drying. Diversion ditches may be necessary along the upper end of cleared slopes to divert melt water and runoff from the cleared soiL After land has been cleared and the debris or moss burned, the remaining mat of moss and fine roots should be broken up by use of a breaking plow o~ a heavy di~k. This should be followed by several harrowmgs. Rototill- ing may be adequate in fields that had only a hght cover of brush. Oats grown for hay is the most widely used crop for newly cleared land. The second year, the land is plowed and disked in the spring and then generally seeded to bromegrass or to oats and peas. Crop Yields and Fertilization Although the freeze-free season in the Fairbanks Area is short~ the almost continuous daylight in the summer months effectively reduces the nmnber of days required for crops to mature. Gains in weight are rapid, and plant tissues are high in sugar and protein. Some plants~ how- ever, are unable to adapt to the long hours of light in this subarctic environment. For example, leafy vegetables like spinach and chard may bloom before vegetative develop- ment is completed. In addition, some legumes that are normally winter-hardy do not build up enough reserves before freezing weather to survive their first-winter ( 6) . Most of these problems will gradually be solved through the development of plant varieties that are better adapted to the growing conQ.itions of this latitude. Crop yields in the Fairbanks Area depend considerably on the intensity of fertilization. Heavy applications of a complete fertilizer--one that contains mtrogen~ phos- phate, and potash-are needed for production of good yields on all soils in the Area, including those newly cleared. Newly cleared-soil needs large quantities of nitrogen because much of this element is used by bacteria in decomposing the native organic material. Application of fertilizer in excess of the minimum rate established by the University of Alaska (193) usually results in higher yields. Continuous cultivation has the tendency to break down the natural structure of the soil; consequently, peri- odic applications of manure or other organic matter are needed to help maintain good tilth. In most years, midsummer moisture levels in the well- ~ra~ned soils o.f the -4-re~ are less t.han optimum. Pre- hmmary expenments mdiCate that yields can be increased through use of sprinkler irrigation but data on the effeets of irrigation are not yet available. ' In this relatively new agricultural area yields from ~oils suitable for cultivation appear to. be 1;1ore strongly mfl.uenced by management than by differences in soils. However, as more land is cultivated, and as farmina procedures become more standardized, yields and aclapta":: bilities of crops will reflect soil differences to a greater extent. At present there are not enough data to establish quantitative differences in productivity of the soils. The estimated yields per acre of principal crops in the Fairbanks Area are shown in table 5. These estimates are based on yields from soils now in cultivation. Most culti- vated soils are the nearly level to moderately sloping, deep to moderately deep Salchaket, Fairbanks, and Minto soils. There is but little cultivation of the poorly drained, very shallow, or steep soils. On these soils it is likely that some of the crops listed cannot be grown and that yields of most crops will be lower than stated. Yield estimates are made for soils under two levels of management, average and improved. Average manage- ment includes the use of only the minimum recommended amounts of fertilizer, the return of little or no organic matter to the soil, and the use of only a few or no erosion control practices. Improved management includes the use of fertilizer at the rates determined by soil tests, the use of manure or green manure every 3 or 4 years, the growing of grass at fairly regular intervals~ and the use of simple erosion control practices where necessary. Because of the small acreage per farm in crops, few farm- ers in the Area use a standard or systematic rotation of crops. Yields shown in table 5 are averages over periods of several years. Abnormal crop seasons~ past management, and the possible effects of irrigation were not considered. TABLE 5.-Estimated average yields per acre of principal crops under two levels of management Crop Potatoes _____________________________ tons __ Barley ____________________________ bushels __ Oats ______________________________ bushels __ Bromegrass hay ______________________ tons __ Bromegrass silage _____________________ tons __ Oat-pea silage ________________________ tons __ Capability Groups of Soils Average Im- manage-proved ment manage- ment 6--7 30-35 40-;-45 lYz---2 5-6 4-5 10-12 50-60 60-70 27'z--3 7-9 8--10 The capability classification is a grouping of soils that shows, in a general way~ how suitable they are for most kinds of farming. It is a practical grouping based on limitations of the soils~ the risk of damage when they are used, and the way they respond to treatment. 18 SOIL SURVEY SERIES 19 59, NO. 2 5 In this system all the kinds of soil are grouped at three levels, the capability class, subclass, and unit. The eight capability classes in the broadest grouping are designated by Roman numerals I through VIII. In class I· aFe the soils that have few limitations, the widest range of use, and the least risk of damage when they are used. The soils in the other classes have progressively greater natural limitations. In class VIII are soils and landforms so rough, shallow, or otherwise limited that they do not pro- duce )Vorthwhile yields of crops, forage, or wood products. The subclasses indicate major kinds of limitations within the classes. Within most of the classes there can be up to four subclasses. The subclass is indicated by add- ing a small letter, e, w, s, or o, to the class numeral, for example lie. The letter e shows that the main limitation is risk of erosion unless close-growing plant cover is main- tained; 'W means that water in or on the soil will interfere with plant growth or cultivation (in some soils the wetness can be partly corrected by artificial drainage) ; s shows that the soil is limited mainly because it is shallow, droughty, or stony, and o, used in only some parts of the country, indicates that the chief limitation is climate that is too cold or tDo dry. In class I there are no subclasses, because the wils of thi.s class have few or no limitations. Class V can contain, at the most, only subclasses w, s, and o, because the soils in it have little or no erosion hazard but have other limita- tions that limit their use largely to pasture, range, wood- land, or wildlife. There are no class I nor class V soils in the Fairbanks Area. Within the subclasses are the capability units, which are called management groups. The soils in one management group are enough alike to be suited to the same crops or other plants, to require similar management, and to have similar productivity and other responses to management. Thus, the capability unit or management group is a con- venient grouping for making many statements about management of soils. Capability units are generally identified by numbers assigned locally. Soils are classified in capability classes and subclasses and management groups in accordance with the degree and kind of their permanent limitations; but without con- sideration of major and generally expensive landforming that would change the slope, depth, or other character- istics of the soil; and without consideration of possible but unlikely major reclamation projects. The six classes and the subclasses and management ·groups in the Fairbanks Area, are described in the list that follows. In this list, the capability unit designa- tion ·is given in parentheses following the management group number. Class II. Soils that have some limitations that reduce the choice of plants or require moderate conservation practices. Subclass IIc.-Soils for which the choice of crops is limited only by climatic factors. Management group 1 (Ilc-1): Deep, medium- to coarse-textured, well-drained, alluvial soils; permafrost deep or absent. Management group 2 (IIc-2) : Deep, medium- textured, well-drained, nearly level soils of up- lands; not susceptible to thermokarst pitting after clearing. Management group· 3 (IIc-3) : Deep, medium- textured, moderately well drained, nearly level soils of uplands; susceptible to thermokarst pitting after clearing. Subclass IIe.-Soils subject to moderate erosion if not protected. Management group 4 (Ile--1): Deep and mod- erately deep, medium-textured, well-drained, gently sloping soils; not susceptible to thermokarst pitting after clearing. Management group 5 (Ile--2) : Deep, medium- textured, moderately well drained, gently slop- ing soils of uplands; susceptible to thermokarst pitting after clearing. Subclass IIs.-Soils that have moderate limitations because of shallowness to excessively permeable substrata. Management group 6 (Ils-1): Moderately deep, wellcdrained, medium-to coarse-textured, alluvial ·soils; permafrost deep or absent. Class III. Soils that have severe limitations that reduce the choice of plants, or require special conservation practices, or both. . · Subclass IIIe.-Soils subject to severe erosion if they are cultivated and not protected. Management group 7(IIIe--1): Deep and mod- erately deep medium-textured, well-drained, moderately sloping soils; normally not suscep- tible to thermokarst pitting after clearing. Management group 8 (IIIe--2): Deep, mediUm- textured, moderately well drained, moderately sloping soils; susceptible to thermokarst pitting after clearing. Subclass IIIs.-S01ls that have severe limitations caused by shallowness to excessively permeable sub- strata or bedrock. Management group 9 (IIIs-1): Shallow, me- dium-to coarse-textured, well-drained, alluvial soils; permafrost deep or absent. Management group 10 (IIIs-2) : Shallow, m~dium-textured, well-drained, gently sloping SOils. Subclass IIIw.-Soils that have severe limitations because of excess water. Management group 11 (IIIw-1): Deep, medi- um-textured wils of the alluvial plain; imper- fectly drained because of permafrost within 30 inches of soil surface. Class IV. Soils that have very severe limitations that restrict the choice of plants, require very careful management, or both. Subclass IV e.-Soils subject to very severe erosion if they are cultivated and not protected. Management group 12 (IV e-1) : Deep and mod- erately deep, medium-textured, well-drained, moderately steep soils. Subclass IVs.-Soils that have very severe limita- tions caused by shallowness to excessively permeable substrata or to bedrock. Management group 13 (IVs-1): Shallow to very shallow, medium-to coarse-textured, well- drained to excessively drained, level to moderately sloping soils. FAIRBANKS AREA, ALASKA 19 Subclass IV w.-Soils that have very severe limitations for cultivation because of excess water. Management group 14 (IVw-1): Deep, medi- um-textured, poorly drained, level to sloping, alluvial soils that are underlain by permafrost. Management group 15 (IVw-2): Deep, medi- um-textured, gently sloping to moderately sloping soils in upland drainageways and on north-facing hillsides; poorly drained because of high permafrost table. Class VI. Soils that have severe limitations that make them generally unsuitable for cultivation and that limit their use largely to pasture or range. Subclass VIe.-Soils severely limited, chiefly by risk of erosion if protection is not maintained. Management group 16 (VIe-1): Deep and mod- erately deep, medium-textured, well-drained, steep soils. Subclass VIs.-Soils generally unsuitable for culti- vation and severely limited for other uses by shallowness to bedrock. Management group 17 (VI&-1): Shallow to very shallow, medium-textured, well-drained, moderately sloping to moderately steep soils. Subclass VI w.-Soils severely limited by excess water and unsuitable for cultivation. Management group 18 (VIw-1): Deep, medi- um-textured, moderately steep soils on north- facing hillsides; poorly drained because of high permafrost .table. Class VII. Soils that have very severe limitations that make them unsuitable for cultivation and restrict their use largely to grazing, woodland, or wildlife. Subclass VIIe.-Soils unsuited to cultivation and severely limited by risk of erosion if cover is not maintained. Management group 19 (VIIe-1): Medium-tex- tured, well-drained, steep to very steep soils. Subclass VII w.-Soils unsuited to cultivation and very severely limited by excess water. Management group 20 (VIIw-1): Shallow, medium-textured, moderately steep to very steep soils on north-facing slopes; poorly drained because of a high permafrost table. Management group 21 (VIIw-2): Peat soils with a high permafrost table. Class VIII. Soils and land types that have limitations that preclude their use for commercial production of plants and restrict their use to recreation, wildlife, or esthetic purposes. Subclass VIIIs.--Land types that are too stony to sup- port commercial plants. Management group 22 (VIII&-1): Nonsoil areas. Subclass VIIIw.-Land types that are too wet to sup- port commercial plants. Management group 23 (VIIIw-1): Annually flooded areas. Management by Groups of Soils Information is given in this section about the principal management and conservation practices. Specific recom- mendations are not made concerning kinds and amounts of fertilizer, crop nlrieties, or seeuing rates, since recom- mendations change as new information is obtained and new crop varieties are developed. Up-to-elate informa- tion and recommendations on farming in this Area are available in publications of the Alaska Agricultural Ex- periment Station. Soil samples may be mailed to the Agricultural Experiment Station in Palmer for testing and for specific fertilizer recommendations. . )L-\.NAGE:\IEKT GROUP 1 This management group consists of a deep, medium-to coarse-textured, -..veil-drained, alluvial soil, in which per- mafrost is deep or absent. The soil is- Salchaket very fine sandy loam. I£ adequately fertilized, this sandy soil will produce good yields of all crops suited to the climate. It warms more quickly and can be worked somewhat earlier in spring than the silty soils of the Area. Droughtiness re- duces yields in dry summers, but the soil would respond to irrigation. To obtain good yields, fertilize crops regularly accord- ing to the needs determined by soil tests. In addition, apply manure or crop residue regularly to maintain soil structure and tilth. Favorable tilth allows rapid infiltra- tion of surface water and more efficient utilization of mois- ture and plant nutrients. This nearly level soil has no serious erosion hazard. Crops should be seeded as early as possible in spring to re- duce the chance of loss from early frosts. MANAGEMENT GROUP 2 This management group consists of a deep, medium- textured, well-drained, nearly level soil of the uplands that is not susceptible to thermokarst pitting after clear- ing. The soil is- Fairbanks silt loam, 0 to 3 percent slopes. This soil is well suited to all crops that can be grown in the Area. For good yields, crops should be fertilized according to needs determined by soil tests. In addition, manure or crop residue should be added to maintain good tilth. If the supply of organic matter is depleted, the soil becomes firm when dry, and it may form a slowly per- meable crust on the surface. This soil has a moderate water-holding capacity, but it may be dry in midsummer. In most years, irrigation would increase yields. Special erosion control measures are not needed, because the hazard of erosion is low. MANAGEMENT GROUP 3 This management group consists of a deep, medium-tex- tured, moderately well drained, nearly level soil of up- lands that is susceptible to thermokarst pitting after clear- ing. The soil is- Minto silt loam, 0 to 3 percent slopes. This soil is among the most productive in the Area, primarily because it is not likely to be droughty in dry summers. All crops common in the Area can be grown. If good yields are to be obtained, crops should be fertil- ized according to needs determined by soil tests. Addi- tions of organic matter are needed periodically for good tilth. 20 SOIL SURVEY SERIES 1959, NO. 25 There is no serious risk of erosion from runoff. How- ever, fields may become hummocky or badly pitted because of subsidence caused by the melting of subsurface masses of ice. In most places where this occurs, leveling followed by application of fertilizer and organic matter will help restore the field to its original condition. In rare instances all or part of a_ field may have to be abandoned because of pitting. · MANAGEMENT GROUP 4 This management group consists of deep and moder- ately deep; medium-textured, well-drained, gently sloping soils that are not susceptible to thermokarst pitting after clearing. The soils are- Fairbanks silt loam, 3 to 7 percent slopes. Fairbanks silt loam, moderately deep, 3 to 7 percent slopes. The physical properties of these soils are like those of the soil in management group 2. If the same kind of management is applied, yields of crops from these soils can be expected to be comparable to those from the soil in management group 2. The sloping soils of this management group, however, are subject to sheet and gully erosion unless simple con- . servation practices are used. These practices consist of cultivating along the contour, growing row crops in strips, and using grass in the cropping sequence. Organic mat- ter should be applied regularly to maintain soil structure and tilth and to reduce the hazard of erosion. MANAGEMENT GROUP 5 This management group consists of a deep, medium- te~tured, modera;tely well_drained, gently slo~ing soil of the uplands that Is susceptible to thermokitrst pittmg after clearmg. The soil is- Minto silt loam, 3 to 7 percent slopes. This soil, like the one in management group 3, is capable of producing good yields of all crops that can be grown in the area, if adequate fertilizer is applied. It is subject to uneven subsidence, caused by the melting of subsurface ice, and to moderate sheet and gully eroswn. Erosion can be controlled by cultivating along the contour, growing row c~ops in strips, and including grass in the regular croppmg sequence. MANAGEMENT GROUP 6 Tl?-is management group consists of a moderately deep, -me~mm-to coarse-!extured, well-drained~ :tlluvia~ soil, in whlQh permafrost IS deep or absent. This soil Is- Salchaket very fine sandy loam, moderately deep. Thi.s soil is like the ~m~ in management group 1, except that It has gravel withm 3 feet of the surface and is droughty in dry summers. All crops suited to the area can be grown, but they are more likely to be damaged by drought ~han t~10se gr?wi:r~g on. the deeper sandy soil ~f the alluvia~ plam. IrrigatiOn will probably make this soil as productive as the one m management group 1. MANAGEMENT GROUP 7 This management group consists of deep and moder- ately deep, medium-textured, well-drained, moderately sloping soils that are normally not susceptible to thermo- karst pitting after clearing. The soils are- Fairbanks silt loam, 7 to 12 percent slopes. Fairbanks silt loam, moderately deep, 7 to 12 percent slopes. These soils are suitable for all crops adapted to the area and will yield well if fertilized according to needs deter- mined by soil tests. However, they are subject to severe erosion. The soils should be in grass crops at least half of the time, and crop residues should be returned to the soils. This will help to maintain good soil structure, allow water to soak in, and reduce erosion. Contour cul- tivation is always necessary; stripcropping is desirable if small grains or row crops are grown. Many fields, especially those on long slopes below high ridges and those that are irrigated, should be protected by diversion ditches, grassed waterways, and other simple erosion control structures. On the lower slopes where these soils grade to the Minto soils, the melting of subsurface ice may cauj'le tunneling. This is most likely to occur where large volumes of water are concentrated. MANAGEMENT GROUP 8 This management group consists of a deep, medium- textured, moderately well drained, moderately sloping soil that is susceptible to thermokarst pitting after clearing. The soil is- Minto silt loam, 7 to 12 percent slopes. Like the soils in management group 7, this soil is subject to severe erosion. It may also be subject to uneven settling and pitting after clearing. It is normally moister than the soils in management group 7, and crops probably will not need irrigation. Erosion control practices on this soil should include maintaining good soil structure, cultivating on the contour, and stripcropping. If possible, concentrations of water in ditches or waterways should be avoided, as this may result in soil pitting. MANAGEMENT GROUP 9 This management group consists of a shallow, medium- to coarse-textured, well-drained, alluvial soil in which permafrost is deep or absent. This soil is- Salchaket very fine sandy loam, shallow. This sandy soil has a gravel substratum 10 to 20 inches below the surface. All crops suited to the Area can be grown, but shallowness to gravel may interfere with the production of potatoes and other root crops. In most summers, drought reduces yields unless the soil is irrigated. Suitable management for this soil'is essentially the same as that for the soil in management group 1. MANAGEMENT GROUP 10 This management group consists of a shallow, medium- textured, well-drained, gently sloping soil. The soil is- Gilmore silt loam, 3 to 7 percent slopes. All crops suited to the Area can be grown on the soil. Management needs are similar to ~hose of management group 4, but shallowness to bedroc~ may interfere with the cultivation of potatoes and bther root crops. Crops on this soil may be damaged by drought. In addition, the so!l is on high ridges, and the danger to crops from frost IS greater than on most other upland soils. FAIRBANKS AREA, ALASKA 21 MANAGEMENT GROUP 11 In this management group is a deep, medium-textured soil of the alluvial plain that is imperfectly drained be- cause permafrost is within 30 inches of the soil surface. The soil is- Tanana silt loam. Ground water perched above the permafrost keeps un- cleared areas of this -soil permanently wet. After the native vegetation and mossy ground cover have been re- moved, the soil thaws to greater depths. As a result it becomes dry enough in a year or two to allow cultivation without artificial drainage. Shallow ditches are needed in some fields to carry off excess water early in spring. The removal of this water allows crops to be seeded earlier and reduces the hazard of frost late in summer. All crops suited to the Area can be grown on this soil. Good yields can be obtained by applying fertilizer in amounts indicated by soil tests. Good tilth can be main- tained by periodically adding manure or crop residue and by including grass in the cropping sequence. MANAGEMENT GROUP 12 This management group consists of deep and moder- ately deep, medium-textured, well-drained soils that are moderately steep. These soils are- Fairbanks silt loam, 12 to 20 percent slopes. Fairbanks silt loam, moderately deep, 12 to 20 percent slopes. If cleared of trees, these soils are subject to severe ero- sion. They can be cultivated with reasonable safety, how- eyer, if suitable precautions are taken. More than half the tim.e, fields.sho~ld be in grass crops or U?ed for pasture in which grazmg IS controlled. Small grams and row crops should be grown in strips. Diversion ditches and perma- nently grassed waterways are desirable in many places. An irregular surface, caused by shallow swales and low ridges running up and down slope, makes many areas suitable only for grass. If crops other than ·grass are to be grown regularly, these soils should receive regular additions of manure or of crop residue to maintain structnre and control erosion. l\IANAGEl\IEXT GROUP 13 This management group consists of shallow to very shallow, medium-to coarse-textured, level to moderately sloping soils that are well drained to excessively drained. These soils are- Chena very fine sandy loam. Gilmore silt loam, 7 to 12 percent slopes. Gilmore silt loam, very shallow, 3 to 7 percent slopes. If cleared, these soils can be used only for grass crops, pasture, garden vegetables, and, possibly, small grains. They are too shallow, as a rule, for the productwn of potatoes and other root crops. They are subject to mid- summer drought. "\Vhere feasible, irrigation will increase crop yields, but it is doubtful if yields will be as high as the a yerage for the Fairbanks Area. On the sloping soils, contour cultivation and strip- cropping are essential if crops other than grass are grmvn. The amounts and kinds of fertilizers needed for crops should be determined by soil tests. Organic matter should be added to cultivated fields to help maintain tilth an_cl to increase the moisture-supplying capacity of these SOils. l\:IA~AGEl\fENT GROUP 14 This management group consists of deep med1um-tex- tured, poorly drained, level to sloping, allu;,ial soils that are underlain by permafrost. These soils are- Bradway very fine sandy loam. Goldstream silt loam, 0 to 3 percent slopes. . Under natural conditio'n.s, these soils contain water far m excess of field capacity. The removal of most of the surface mat of moss and the construction of open ditches are needed to reduce the 'vater level enough to make culti- vation possible. J?itches must I;>e deep eno~1gh to allow for subsidence, wluch accompames the meltmg of permafrost following the removal of the surface moss. Some areas of these soils are in depressions or in narrow channels of old streams and have no suitable outlet for ditches. These areas cannot be drained and are comparable to the soil in management group 21. Even if drained, the soils of this management group dry out more slowly in spring than other soils in the Area. As a result, planting dates are late and only grains, grasses, some vegetables, and other short-season crops ?an be grown. Even these may be damaged by frost late m summer. Grasses should not be grown consecutively for more than 4 years, because they insulate the soil and encourage the return of permafrost to its former high level. Good tilth is essential for proper mmsture relations in these soils. Tilth can be maintained in most fields by occasionally adding organic matter and not working the soil when it is wet. Fertilizers should be applied accord- ing to needs determined by soil tests. MANAGEMENT GROUP 15 This management group consists of deep, medium-tex- tured, gently sloping to moderately sloping soils in upland drainageways and on north-facing hillsides. These soils are poorly drained because the permafrost table is near the surface. Soils in this group are- Goldstream silt loam, 3 to 7 percent slopes. Goldstream silt loam, 7 to 12 percent slopes. Saulich silt loam, 3 to 7 percent slopes. Saulich silt loam, 7 to 12 percent slopes. These soils are much wetter than those in comparable positions on south-facing slopes. "\Vetness is caused by the permafrost and by the constant inflow of seep water from the poorly drained soils on higher slopes. Remov- ing the surface moss and diverting the seep water from cleared fields will reduce the moisture and allow the soils to warm. Open ditches are needed to remove "·ater in spring, because these soils get less direct sunlight than other soils and are naturally slower in warming. Low soil temperatures and the necessity of late planting limit the choice of crops to grains, grasses, and some veg- etables. Good tilth can be maintained by occasionally adding organic matter and by not tilling the soils when "·et. Fertilizer is needed in amounts shown by soil tests. l\IANAGEl\IE~T GROUP 16 This management group consists of deep and moder- ately deep, medium-textured, steep soils that are well drained. Soils in this group are- Fairbanks silt loam, 20 to 30 p~:>rcent slopes. Fairbank;; silt loam, nH><l~:>rately dt:>~:>p, 20 to 30 percent 1;lopes. 22 SOIL SURVEY SERIES 1959, NO. 25 Deep gullies will :form in these soils i:f they are used :for crops other than grass. I:f the native :forest is removed, the soils should be kept in permanent meadow or pasture. Overcutting or overgrazing o:f grass should be avoided, as a continuous, firm sod is necessary to hold these soils in place. Renovation o:f meadow or _pasture should be accom- plished by disking and reseedmg without turning under the old sod. New seedings and established grass require :fertilizer in amounts determined by soil tests. MANAGEMENT GROUP 17 This management group consists o:f shallow to very shallow, medium-textured, well-drained, moderately slop- ing to moderately steep soils. These soils are- Gilmore silt loam, 12 to 20 percent slopes. Gilmore silt loam, very shallow, 7 to 12 percent slopes. Gilmore silt loam, very shallow, 12 to 20 percent slopes. Even a small amount o:f erosion may expose bare rock and result in permanent loss o:f productivity o:f these soils. Consequently, the soils should have a permanent cover o:f vegetation consisting o:f either grass or trees. Grass should not be overcut or overgrazed. Seedings are more difficult to establish on these soils than on the deeper soils because stones interfere with tillage. Fertilization, in- cluding topdressing, is needed. Apply :fertilizer in amounts indicated by soil tests. MANAGEMENT GROUP 18 This management group consists o:f a deep, medium- textured, moderately steep soil on north-:facing slopes that is poorly drained because o:f a high permafrost table. The soil i&- Saulich silt loam, 12 to 20 percent slopes. Because o:f the permafrost, the constant inflow o:f seep water :from poorly drained soils on higher slopes, and the low amount o:f direct sunlight, this soil is much wetter than those in comparable positions on south-facing slopes. Diversion ditches :for intercepting seep water are needed to make the soil suitable :for agriculture. Even though seep water is diverted, this soil is too limited by low soil temperatures and steepness o:f slope to be used :for hay and pasture grasses. Fertilization, as determined by soil tests, will be necessary :for sustained good yields o:f :forag-e. Overgrazing must be avoided i:f gullying is to be prevented. MANAGEMENT GROUP 19 --This management group consists o:f medium-textured, well-drained, steep to very steep soils. These soils are- Fairbanks silt loam, 30 to 45 percent slopes. Fairbanks silt loam, moderately deep, 30 to 45 percent slopes. Gilmore silt loam, 20 to 30 percent slopes. Gilmore silt loam, 30 to 45 percent slopes. Gilmore silt loam, very shallow, 20 to 30 percent slopes. Gilmore silt loam, very shallow, 30 to 45 percent slopes. The removal o:f the native :forest would create a very severe erosion hazard. Consequently, :forest is by :far the best use o:f these soils. The soils can be used :for pasture i:f a vigorous stand o:f grass is maintained and grazing is carefully regulated. In addition, nitrogen and other :fer- tilizer must be applied to obtain high yields of :forage. MAXAGE:\IENT GROUP 20 This management group consists o:f shallow, medium- textured, moderately steep to very steep soils on north- facing slopes that are poorly drained because o:f a high permafrost table. The soils are- Ester silt loam, 12 to 20 percent slopes. Ester silt loam, 20 to 30 percent slopes. Ester silt loam, 30 to 45 percent slopes. These soils are not suitable :for cultivation and should not be cleared o:f their native vegetation. They receive little direct sunlight. Controlled burning on these· soils may create conditions that :favor the establishment o:f paper birch. Stands o:f birch may have commercial value. The native sedges and grasses that grow on these wet, moss-covered soils can be grazed. Forage yield is very low. MANAGEMENT GROUP 21 This management group consists o:f a peat soil that has a high permafrost table. The soil is-_ Lemeta peat. This soil is always W31terlogged and cannot be drained. Some o:f the surface is covered by small ponds and sloughs. Sedges and grasses growing on the bogs can be grazed, but the amounts o:f :forage available to :farm livestock is small. MANAGEMENT GROUP 22 This management group consists o:f nonsoil areas. These areas, or land types, are- Gravel pits. Mine tailings. The areas are bare gravel that have no value :for agri- culture or :forestry. They support only a :few bushes or alder and willow. MANAGEMENT GROUP 23 This management group consists o:f areas flooded annu- ally. The land type i&- Alluvial land. This land type is along the large rivers and is :frequently flooded. It is not suitable :for agriculture or :forestry. It supports some vegetation that is o:f benefit to wildlife. Engineering Applications This section is :for engineers and others who want in- formation about use o:f soils in structures. Most o:f the information is presented in three tables. Table 6, on physi- cal properties o:f soils that affect engineering, and table 7, on :features affecting use o:f soil materials :for highways or agricultural structures, are based partly on the tests o:f soil samples shown in table 8. These tables, with the soil map and the information on soils given elsewhere in the report, can be used by engineers to-- 1. Make soil and land-use studies that will aid in selecting and developing industrial, business, resi- dential, and recreational sites. 2. Make preliminary estimates o:f the engineering properties o:f soils in planning drainage and irri- I l t e 0 FAIRBANKS AREA, ALASKA 23 gation systems and other structures for soil and water conservation. 3. Make preliminary evaluations of soil conditions that will aid in selecting highway and airport lo- cations and in planning detailed investigations of the selected sites. 4. Loeate sources of sand and gravel. 5. Correlate performance of existing structures with soil types and thus develop information that can be useful in designing and maintaining future structures. 6. Determine the suitability of soils for off-road movement of vehicles and construction equipment. It must be emphasized, however, that the soil map and the descriptions of the soils in t;his report are generalized. The report therefore should be used only in planning the more detailed field surveys that will need to be made to determine the in-place condition of the soil at the site pro- posed for construcfiion. Some of the terms used in this report have special mean- ings to soil scientists that do not correspond with the meanings assigned to the sanie terms by engineers or others concerned with soil mechanics. The following commonly used terms are defined a~cording to their special meaning in soil science. Soil.-The natural, three-dimensional medium for the growth of land .Plants, on the earth's surface, that has pro_perties resultmg from the combined effect of climate and living matter acting on parent material, as condi- tioned by relief, over periods of time. Deep, unconsoli- dated materials not affected hy soil-forming processes other than mechanical weathering, and below the reach of plant roots, normally are not considered to be soil. Substraflum.-Any layer lying beneath the solum or true soil. It is applied to both parent materials and to other layers unlike the parent material, below the B ho- rizon, or the subsoil. Tewture, soll.-The relative proportions of the various size groups of individual particles in a mass of soil. Spe- cifically, the proportions of sand, silt, and clay. Coarse- textured or coarse-grained soils contain a' high proportion of sand; fine-grained soils are high in clay. Tewtural class.-A defined range in percentages of particles in each size class. Only 'mineral particles finer than 2.0 millimeters are considered in the definition of basic textural classes. Terms like "gravelly" or "mucky," which indicate the presence of large amounts of coarser particles or organic matter, may be used to modify the basic textural class names. Textural classes are defined in . terms .of size distribution. Gradation and .plastic prop- erties of the soil are not directly considered in the definition of textural classes. Sand: (1) As a soil separate, individual rock or mineral partwles ranging in diameter from 2.0 milli- meters (No. 10 sieve) to 0.05 millimeter. (2) As a text1,1ral class, soil material that contains 85 percent or more of sand but in which the percentage of silt plus 11;2 times the percentage of clay does not exceed 15. The textural class name is normally modified to indicate the dominant size of sand particles; for ex- ample; very fine sand, coarse sand, and so on. Silt: (1) As a soil separate, individual mineral particles that range in diameter between the upper size limit-of clay, 0.002 millimeteri and the lower size limit of very fine sand, 0.05 mil imeter. ( 2) As a textural class, silt contains 80 percent or more silt- size particles and less than 12 percent clay. Clay : ( 1) As a soil separate, the mineral particles less than 0.002 millimeter in diameter. (2) As a tex- tural class, soil materi~l that contains 40 percent or more of clay, less than 45 percent sand, and less than 40 perc~nt silt. Loam: The textural class name for soil that con- tains 7 to 27 percent cla_y, 28 to 50 percent silt, and less than 52 percent sand. The word loa;m is part of other textural class names as, for example, silt loam. This class name indicates textural properties between those of a loam and those of soils of the silt class. Definitions of other terms used in this report are given in the Soil Survey Manual (10). Engineerin~ Soil CJassification Systems Most highway engineers classify soil material according to the system approved by the American Association of State Highway Officials ( 1) . In this system, soil mate- rials are classified in seven principal groups. The groups range from A-1, which consists of gravelly soil of high bearing capacity, to A-7, which consists of fine-grained soils having low strength when wet. In eacP, group, rela- tive engineering value of' the soil material is indicated by a group index number. Group index numbers range from 0 for the best material to 2'0 for the poorest. The group index number is shown in parentheses, following the soil group symbol. Some engineers prefer to use the Unified soil classifica- tion system (13). In this system, soil materials are iden- tified as coarse grained, 8 classes; fine grained, 6 ·classes; and highly organic soils. An approximate classification of soils by this system can be made in the field. Soils are classified according to both systems in tables 6 and 8 in this part of the report. Soil Characteristics Significant to Engineering A brief description of the soils mapped in the Fairbanks Area and the estimated physical properties significant to engineering are given in table 6. Additional information about the soils can be obtained in the sections "Descrip- tions of the' Soils" and "Formation, Classification, and Morphology of the Soils." The interpretations of engirieering properties of soils are given in table 7. Specific features or characteristics of soils that may affect engineering practices and estimates of the suitability of the soils for specific purposes are listed. The listing of features and the suitability ratings are based on information in table 6, actual test data avail- able (table 8) , and field experience. . Bri~f statem~nts about soil features that affect the engmeermg practices follow. 24 SOIL SURVEY SERIES 1959, NO. 25 TABLE 6.-Brief description of soils and Symbol on map Ad Br Ch EsD EsE EsF FaA FaB FaC FaD FaE FaF FmB FmC FmD FmF GmB GmC GmD GmE GmF Soil name Alluvial land. Depth from surface to- Seasonally Permafrost high water table 2 table 1 Bedrock or alluvial gravel Feet Feet Feet Description of soil and site Less than L _ _ _ _ _ _ _ _ _ _ _ _ Less than L Thin, silty mantle over rounded al- luvial gravel; ad- jacent to river and frequently flooded. Bradway very fine sandy Less than L 3 to 4 ______ Morethan6 Poorly drained, very loam. fine sandy soil in old stream chan- nels of alluvial plain. Chena very fine sandy 6 to 1 0_ _ _ _ _ More than Less than L Excessively drained, very shallow, sandy soil over rounded, alluvial gravel. loam. 15. Ester silt loam, 12 to 20 percent slopes. Less than L Less than L 1 to 2 ______ Poorly drained, Ester silt loam, 20 to 30 percent slopes. Ester silt loam, 30 to 45 percent slopes. Fairbanks silt loam, 0 to 3 More than percent slopes. 15. Fairbanks silt loam, 3 to 7 percent slopes. Fairbanks silt loam, 7 to 12 percent slopes. Fairbanks silt loam, 12 to 20 percent slopes. Fairbanks silt loam, 20 to 30 percent slopes. Fairbanks silt loam, 30 to 45 percent slopes. Fairbanks silt loam, mod-More than erately deep, 3 to 7 per-15. cent slopes. Fairbanks silt loam, mod- erately deep, 7 to 12 per- cent slopes. Fairbanks silt loam, mod- erately deep, 12 to 20 percent slopes. Fairbanks silt loam, mod- erately deep, 20 to 30 'percent slopes. Fairbanks silt loam, mod- erately deep, 30 to 45 percent slopes. Gilmore silt loam, 3 to 7 percent slopes. Gilmore silt loam, 7 to 12 percent slopes. Gilmore silt loam, 12 to 20 percent slopes. Gilmore silt loam, 20 to 30 percent slopes. Gilmore silt loam, 30 to 45 percent slopes. More than 15. shallow, silty soils over bedrock on north slopes of ridges; normally frozen. None ______ 3 to 6+----Well-drained, deep, silty soils of up- lands. None ______ 2 to 3 ______ Well-drained, mod- erately deep, silty soils of uplands. None______ 1 to 2___ _ __ Well-drained, shal- low, silty soils of uplands. See footnotes at end of table. [Dashes in columns indicate Depth from surface (typical profile) Inches Classification USDA texture 0 to 60+---Very gravelly sand. 0 to 2 ______ Mucky silt loam_ 2 to 36+---Very fine sandy loam with lenses of silt loam and fine sand. 0 to 4 ______ Very fine sandy loam. 4 to 7 _ _ _ _ _ _ Fine sand _____ _ 7 to 18+ __ _ Very gravelly sand. 0 to 10 _____ Silt loam ______ _ 0 to 36+---Silt loam to silt __ 0 to 25__ _ _ _ Silt loam to silt __ 25 to 36 (weath- ered bed- rock). Gravelly sandy loam. 0 to 17 _____ Silt loam to silt __ 17 to 24_ _ _ _ Gravelly sandy loam. 11 c FAIRBANKS AREA, ALASKA 25 their estimated physical properties data are not available] Classification-Con. Percentage passing sieve- Shrink- Permeability a Available Reaction Dispersion 5 swell No.4 No. 10 No. 200 water 4 potential6 Unified AASHO (4.76 mm.) (2 mm.) (0.74 mm.) Inches per foot Inches per hour of depth pH value GW-GM ___ A-1-a _____ 60 to 75 40 to 50 5 to 10 More than -------------------------Low _______ Low. 6.0. OL_-_ -----A-5 _______ 100 100 60 to 70 0.6 to 2.0 ____ 1.5 to 2.0 ____ 6.0 to 6.5 ___ High _______ Moderate. ML ________ A-4 _______ 100 95 to 100 50 to 60 . 6 to 2.0 _____ 1.5 to 2.0 ____ 7.5 to 8.0 ___ Moderate __ Low . ML ________ A-4 _______ 100 95 to 100 50 to 60 .6 to 2.0 _____ 1.0 to 2.0 ___ , 5.0 to 6.0 ___ Moderate __ Low. SP-SM _____ A-3 _______ 100 90 to 100 5 to 10 2.0 to 6.0 __ :_ .5 to 1.0 _____ 6.0 to 6.5 ___ Low _______ Low. GW ________ A-1-a _____ 60 to 75 40 to 50 0 to 5 More than More than ------------Low _______ Low. 6.0. 0.5. ML ______ --A-4 _______ 100 100 85 to 95 .2 to 0.6 _____ (7) __________ 4.0 to 5.0 ___ High _______ Moderate. ML, ML-A-4, A-5 __ 100 ______ 100 _______ 85 to 100_ .2 to 0.6 _____ 2.0 to 2.5 ____ 5.0 to 6.5 ___ High _______ Low. CL. ML, ML-A-4 _______ 100 ______ 100 _______ 85 to 95 __ .2 to 0.6 _____ 2.0 to 2.5 ____ 5.0 to 6.0 ___ High _______ Low. CL. GM ________ A-1-b ____ 50 to 60_ 30 to 40 __ 15 to 25 __ .2 __________ -------------6.0 to 6.5 ___ Low _______ Low. ML ________ A-4 _______ 100 ______ 100 _______ 85 to 95_ .2 to 0.6 _____ 2.0 to 2.5 __ 5.0 to 6.0 ___ High _______ Low. GM ________ A-1-b _____ 50 to 60_ 30 to 40 __ 15 to 25_ Less than 0.2_ -------------6.0 to 6.5 ___ Low _______ Low. 26 SOIL SURVEY SERIES 1959, NO. 25 TABLE 6.-Brief description of soils and I ' Depth from surface to-Classification Symbol Soil name on map Seasonallv Permafrost high water table 2 table 1 Feet Feet GrB Gilmore silt loam, very More than None ______ shallow, 3 to 7 percent slopes. 15. GrC Gilmore silt loam, very shallow, 7 to 12 percent slopes. GrD Gilmore silt loam, very shallow, 12 to 20 percent slopes. GrE Gilmore silt loam, very shallow, 20 to 30 percent slopes. GrF Gilmore silt loam, very shallow, 30 to 45 percent slopes. GtA Goldstream silt loam, 0 to Less than L 1 to 3 ______ 3 percent slopes. GtB Goldstream silt loam, 3 to 7 percent slopes. GtC Goldstream silt loam, 7 to 12 percent slopes. Lp Lemeta peat. o __________ 1 to 3 ______ Me Mine tailings. More than More than 15. 15. MnA Minto silt loam, 0 to 3 2to3 ______ Variable ____ percent slopes. MnB, Minto silt loam, 3 to 7 percent slopes. MnC Minto silt loam, 7 to 12 percent slopes. Sc Salchaket very fine sandy 10 to 15 ____ None or loam. more Sm Salchaket very fine sandy than 15. loam, moderately deep. Ss Salchaket very fine sandy loam, shallow. SuB Saulich silt loam, 3 to 7 Less than L 1 to 3 ______ percent slopes. Sue Saulich silt loam, 7 to 12 S,uD percent slopes. Saulich silt loam, 12 to 20 '· ' percent slopes. Ta Tanana silt loam. Less than L 2 to 4 ______ 1 Depth to water table before clearing of vegetation. In soils , with permafrost and free water perched above frozen ground, the water table may drop when the surface mat of vegetation is removed. Depth from Description of soil surface Bedrock and site (typical or alluvial profile) USDA texture gravel Feet Inches Less than L Well-drained, very 0 to 8 ______ Silt loam to silt shallow, silty soils 8 to 18 _____ Gravelly sandy of uplands. loam. More than Poorly drained, silty 0 to 4 ______ Silt loam _______ 6. soils of alluvial 4 to 1.9+ Silt loam _______ plains. More than Very poorly drained 0 to 25+---Peat ___________ 6. peat bogs. ------------Coarse, angular 0 to 60+-------------------gravel in gold- dredge fields. More than Moderately well 0 to 30+---Silt loam to silt_ 6. drained, deep, silty soils on foot slopes. 1 to 6 ______ Well-drained, deep 0 to 3 ______ Silt loam _______ to shallow, sandy 3 to 10 _____ Very fine sandy soils over rounded loam. alluvial gravel. 10 to 26 ____ Fine sand ______ 26+ -------Very gravelly sand. 3 to 6+----Poorly drained, 0 to 15+---Silt loam _______ deep, silty soils over bedrock; on north slopes. 4 to 6+----Imperfectly drained, silty soils of 0 to 4 ______ Silt loam _______ alluvial plains. 4 to 20+------------------- 2 The permafrost table drops when the mat of surface vegetation is removed. a Permeability is for soil without compaction; for wet soils, the permeability is that to be expected after removal of free water. Vi " I1 pi FAIRBANKS AREA, ALASKA 27 their estimated physical properties-Continued Classification-Con. Percentage passing sieve- Available Shrink- Permeability 3 water 4 Reaction Dispersion s swell Unified AASHO No.4 No. 10 No. 200 potential6 (4.76 mm.) (2 mm.) (0.74 mm.) Inches per foot Inches per hour of depth pH value ML ________ A-4 _______ 100 100 85 to 95 .2 to 0.6 _____ 2.0 to 2.5 ____ 5.0 to 6.0 ___ High _______ Low. GM ________ A-1-b ____ 50 to 60 30 to 40 15 to 25 Less than -------------6.0 to 6.5 ___ Low _______ Low. 0.2 OL ________ A-5 _______ 100 100 80 to 90 .2 to 0.6 _____ 2.0 to 2.5 ____ 5.0 to 5.5 ___ High _______ Moderate. ML ________ A-4 _______ 100 100 80 to 90 .2 to 0.6 _____ 2.0 to 2.5 ____ 6.5 to 7.0 ___ High _______ Moderate. pt_----------------------------------------------------------------------------4.5 to 5.0 ___ ------------ GW ________ A-1-a _____ 20 to 30 10 to 20 0 to 5 --------------------------------------------------Low. ML ________ A-4 _______ 100 100 85 to 95 .2to0.6 ____ 2.0 to 2.5 ____ 4.5 to 5.0; High _______ Moderate. grading to 7.5 to 8.0 below 15 inches. ML ________ A-4, A-5 __ 100 100 80 to 95 .2 to 0.6 ____ 2.0 to 2.5 ____ 5.0 to 5.5 ___ High. ______ Low. ML ________ A-4 _______ 100 100 60 to 90 .6 to 2.0 ____ 1.5 to 2.0 ____ 6.0 to 6.5 ___ Moderate ___ Low. SM or ML __ A-2 or 100 90 to 100 5 to 80 2.0 to 6.0 ____ . 5 to 1.0 ____ 7.5 to 8.0 ___ Low _______ Low . A-4. GP or SP ___ A-1-a or 15 to 70 10 to 60 0 to 5 More than Less than ------------Low _______ Low. A-3. 6.0. 0.5. ML ________ A-4 _______ 100 100 85 to 95 .2 to 0.6 __ --2.0 to 2.5 ____ 5.0 to 6.0 ___ High _______ Moderate. MH, OHor A-4 or 100 95 to 100 70 to 90 ) r·d.,at• to OL. A-7. .2 to 0.6 ____ 2.0 to 2.5. ___ 7.0 to 7.5 ___ High _______ high. ML ________ A-4 or 100 95 to 100 90 to 100 Moderate. A-5. 4 An approximation of capillary water in the soil profile when wetted to field capacity. The amount of water that will wet "air-dry" soil to a depth of 1 foot without deeper percolation. In poorly drained soils, water in excess of this amount is normally present in the soil profile before drainage. 5 Refers to the degree and rapidity with which soil structure breaks down, or slacks, in water. 6 The shrink-swell potential is an indication of the volume change to be expected in the soil with changes in moisture content. 7 Soil is normally frozen; no estimate made. 28 SOIL SURVEY SERIES 1 9 59, NO. 2 5 TABLE 7.-Interpretation of [Dashes in columns indicate Suitability as source of-Soil features affecting engineering practices Soil series and Susceptibility map symbol to frost action Road sub-Road fill Vertical alinement of highways grade (undis-(disturbed Topsoil Sand and gravel turbed rna-material) terial) Material Drainage Alluvial land (Ad)_ --------------Fair to poor; Poor; high Poor _________ Poor; very No adverse High water high water water high water features. table. table. table. table. Bradway (Br) ____ High to mod-Fair to poor __ Poor _______ Fair; usually Poor; uni-No adverse High water erate. wet. formly features. table. graded very fine sandy material. Chena (Ch) ______ Moderate to Good to fair __ Good ______ Fair _________ Good; gravel No adverse No adverse low. substratum. features. features. Ester (EsD, High _________ Fair to poor __ Poor _______ Poor_--------Poor; bed-Shallowness to Wet or frozen EsE, EsF). rock near bedrock. under natural surface. vegetation. Fairbanks (FaA, High to mod-Fair to poor __ Fair to poor; Good ________ Poor to not Shallow to bed-No adverse FaB, FaC, FaD, erate. erodible. suitable. rock in places; features. FaE, FaF, FmB, erodible in FmC, FmD, cut slopes. FmE, FmF). Gilmore (GmB, High to Fair to poor __ Poor to Good, but Poor; bedrock Shallow to No adverse GmC, GmD, moderate. fair; erod-shallow to near surface. bedrock. features. GmE, GmF, ible. bedrock. GrB, GrC, GrD, GrE, GrF). Goldstream (GtA, High _________ Fair to poor __ Poor _______ Good; usually Unsuitable _____ Deep, silty Wet to surface; GtB, GtC). wet. material with permafrost. permafrost. Lemeta peat High _________ Unsuitable ____ Unsuit-Unsuitable ____ Unsuitable _____ Peat soil with Wet to surface; (Lp). able. permafrost. permafrost. Mine tailings (Me). ----------------------------------------· ------------------------------------------------------------- ', Minto (MnA, High to Fair to poor ___ Poor_ _____ ~ Good ________ Unsuitable _____ Deep, silty Seasonally high MnB, MnC). moderate. material; water table. erodible. Salchaket Moderate to Good to fair_ __ Good ______ Fair _________ Good to fair; No adverse No adverse (Sc, Sm, Ss). low. depth to features. features. gravel sub- stratum variable. FAIRBANKS AREA, ALASKA 29 engineering properties of soils data not applicable] Soil features affecting engineering practices-Continued Farm ponds Remarks Dikes and levees Agricultural Irrigation Terraces and Waterways drainage diversions Reservoir area Embankment Rapid perrneabil----------------------------------------------------------------------------------------Frequently ity. flooded. Moderate per-Moderate per-Moderate per-High water High water (Not needed)_ (Not needed)_ Ground water meability; · meability; meability; table; mod-table. perched high water high water instability. erate per-above per- table. table. meability. mafrost. Rapid perme-Rapid perme-Good stability; (Not needed)_ Low water-(Not needed)_ (Not needed)_ ability. ability. rapid per-holding ca- meability. pacity; rapid permea- bility. ----------------Shallowness to Poor stability __ -----------------------------Shallowness --------------Perennially bedrock. to bed-frozen un- rock. der natural vegetation. Susceptibility Susceptibility Poor stability __ (Not needed)_ Moderate wa-High erodi-High erodi- to piping. to piping. ter-holding bility. bility. capacity; moderate permea- bility. Silty material; Shallowness to-Silty material (Not needed)_ Moderate High erodi-High erodi- susceptibil-bedrock. has no water-hold-b)lity. bility. ity to piping; stability; ing capacity. weathered weathered bedrock bedrock has stable. good sta- bility. Silty material; High water Poor stability __ High water High water Moderate Moderate Ground water susceptibility table; table; table. erodibility. erodibility. perched to piping. permafrost. moderate above per mea-perm3Jrost. bility. Peat soil ________ High water Peat soiL _____ High water High water (Not needed)_ (Not needed)_ table; table. table. permafrost. -------------------------------------------------------------------------------------------------------Good source of coarse aggregate. Silty material; Susceptibility Poor stability __ Moderate Moderate High erodi-High erodi-Melting of susceptibility to piping. per mea-water-hold-bility. bility. underground to piping. bility. ing capacity. ice masses may result in irregular subsidence or pitting. Rapid permea-Rapid permea-Good stability; (Not needed) _ Low to moder-(Not needed)_ (Not needed) _ Silty lenses in bility. bility. rapid perme-ate water-subsoil may ability. holding impede capacity; drainage. rapid per me- ability. I 30 SOIL SURVEY SERIES 1959, NO. 25 TABLE 7.-Jnterpretation of Suitatility as source of-I Soil features affecting engineering practices Soil series and Susceptibility map symbol to frost action Road sub-Road fill grade (undis-(disturbed turbed rna-material) terial) Saulich (SuB, High _________ Fair to poor __ Poor _______ SuC, SuD). Tanana (Ta) _____ High _________ Fair to poor __ Poor _______ Permafrost, or perennially frozen soil, creates many engineering problems in the Fairbanks Area. In the up- lands, perennially frozen subsoil occurs on the north slopes of ridges and in the sloping valleys along the secondary drainageways. On the alluvial plains, large areas of nearly level soils are underlain by permafrost. Removal of the insulating surface moss or litter from these soils causes thawing in the llJ?per part of the permafrost. This is commonly accompamed by subsidep.ce of the overlying soil. Roads and structures on these soils may settle till- evenly unless special construction methods are used. Level and sloping soils .are nearly always saturated in summer in the zone above permafrost. . Failure to remove excess water, especially along roads, often results in even more unsettled conditions because of seyere heaving of soil in spring. There is an additional hazard in areas of ~Iinto soils on foot slopes. In these areas very irregulat subsidence or, in some places, the formation of deep, steep- walled pits may be caused by the melting of underground masses of ice. Frost action in soils with and without permafrost is a . major problem in all soils of the Area. A precise corre- la-tion has not been established, but it is believed that in the 'Fairbanks Area only soils containing less than 3 per- cent of material finer than 0.07± millimeter (No. 200 sieve) can be considered nonsusceptible to heaving by frost. Except for the gravelly substratum under the soils of the \ Vertical alinement of highways Topsoil Sand and gravel Material Drainage Good, but Not suitable ___ Deep, silty Wet to usually wet. material surface; with perma-permafrost. frost. Good, but Fair to poor; Deep, silLy Wet to surface; usually wet. depth to material permafrost. gravel sub-with perma- stratum frost. variable. alluvial plains, no soil that occurs naturally in the Fair- banks Area can meet this requirement. The rating of a soil as to its susceptibility to frost action depends on the texture of the soil material and the depth to the high water table during the freezing period. Silt and fine sand with a high water table are rated "High." Because of the difficulty in maintaining proper control of moisture for compaction when soil is frozen, the con- struction of embankments and other earthworks with frost-susceptible material should be avoided in winter. The suitability of a soil for "Road subgrade ( undis- turbed material)" depends on its texture, natural water content, and the depth to the water table and permafrost. Silty or fine sandy soils with a high water table and shal- low depth to permafrost are rated "Fair to poor." Where the permafrost and water table are deep and the soils are sandy, the soils are rated "Good to fair." Muck and peat soils are rated "Unsuitable." The suitability of a soil for "Road fill (disturbed ma- terial)" depends largely on the texture of the soil, its na- tural water content, and depth to permafrost. Soils with a shallow zone of permafrost are rated "Poor."-Highly erodible silty soils are rated "Fair to poor." Sandy and gravelly soils where permafrost is deep, or not present, are rated "Good." On the alluvial plain, most soils are underlain by a thick deposit of row1ded, well-graded gravel. The thickness of the finer material over the gravel is variable. In the Gold- n( sel dil f~ to' th~ mt bel sid fa1 wa f wiJ qu: rna pOI FAIRBANKS AREA, ALASKA 31 engineering properties of soils-Continued Soil features affecting engineering practices-Continued Farm ponds Dikes and levees Agricultural drainage Reservoir area Embankment Silty material; High water Poor sta-High water susceptibil-table; perma-bility. table; ity to frost; sus-moderate piping. ceptibility permea- to piping bility. after clearing. Silty material; High water Poor sta-High water susceptibility table; bility. table; to piping. permafrost. moderate permea- bility. stream soils, the gravel under frozen silty material is gen- erally so deep that it cannot be excavated economically. In many areas of Tanana soil, the gravel can be reached fairly easily .. The gravel is most readily excavated from the Chena seiil and from the shallow and moderately deep Salchaket soils. In many places, however, the water table is high enough to interfere with excavation. In the uplands, angular gravel from weathered schist can be obtained from the gently or moderately sloping Gilmore soils near the tops of ridges and from Mine tail- ings in the valleys. As a rule, the other upland soils are not a suitable source of gravel. · The sloping, silty soils of the uplands are subject to severe gully erosion. For prevention of gullying, road ditches and diversion ditches in fields should be at least 2 feet deep, have side slopes of a gradient no steeper than 3 to 2, and have a permanent cover of grass. In addition., they must always be free of obstructions. These ditches must be kept open in spring so that water does not pond behind snow or ice. Lateral ditches in fields should have side slopes of about 5 to 1, so that they can be crossed with farm machinery. Grassed ditches, terraces, and water- ways should have a grade of not more than 5 percent. Stock ponds or reservoirs in the uplands must be lined with impermeable material to prevent seepage. Large quantities of water moving through silty upland soils may form subsurface tunnels that can effectively drain the pond. Remarks Irrigation Terraces and Waterways diversions High water High erodi-High erodi-Ground table. bility. bility. water perched above perma- frost. High water (Not needed) __ (Not needed) _ Ground table. water perched above perm a- frost. The silty, well-drained soils of the uplands are not well suited to the off-road movement of vehicles and heavy equipment. After clearing, these soils are very dusty when dry and soft and slipJ?ery when wet. On both up- lands and alluvial plains, s1lty soils with permafrost are wet throughout the summer under natural conditions and will not support repeated passes of equipment. The Chena, Salchaket, and other well-drained, sandy soils, are suitable for cross-country movement of equipment except when they are too dry to provide traction. Other sources of'information on the engineering prop- erties of soils in the Fairbanks Area include published reports by Lindholm, Thomas, and Davidson (3); Pewe (9); Williams (14); and Wmiams, Pewe, and Paige (15). Soil Test Data As shown in table 8, profiles of soils in three of the most extensive soil series in the Fairbanks Area were tested according to standard procedures ( 1) . Samples were chosen to indicate the range in physical properties for each series. For each series, there are test data on three soil profiles. One of these profiles, or at most two of them, represents the modal, or typical, nature of the soil series; the other profiles are within the allowable range of varia- tion for the series but differ from the modal profile in texture, consistence, or some other property significant in engineering. 32 SOIL SURVEY SERIES 19 59, NO. 2 5 TABLE 8.-Engineering Moisture-density s Bureau of Public Soil name and location Parent material Roads Depth Horizon report Maximum Optimum number dry density moisture Fairbanks silt loam: Inches Lb. per cu. ft. Percent SE}~SW%sec. 18, T. 1 N., R. 1 E. (modal) ____ Micaceous loess. S37857 0-3 AI 77 30 S37858 7-21 B2 105 16 S37859 25-40 cl 102 17 NW}~NE}~ sec. 27, T. 1 N., R. 2 E. (!llodal) ___ Micaceous lo::ss. S37860 0-3 AI 83 26 S37861 7-15 B2 104 17 S37862 20-30+ cl 105 16 SW}~SE% sec. 29, T. 1 S., R. 2 W. (slightly Micaceous loess. S37863 0-3 At 82 27 coarser). S37864 6-15 B2 97 19 S37865 26-40 cl 102 16 Salchaket very fine sandy loam: NE;iNW;i sec. 19, T. 1 S., R 2 E. (modal) __ Alluvium (Flood plain). S37866 0-3 AI 76 32 S37867 10-26 c2 93 19 S37868 26-36+ D 127 5 NE;iNE;i sec. 15, T. 1 S., R. 1 E. (thicker Alluvium (Flood plain). S37869 3-16 Ct 84 25 deposit). S37870 16-24 C2 89 22 S37871 24-36+ Ca 90 21 f SE;iNE;i sec. 3, T. 2 S., R. 2 E. (shallower)_ Alluvium (Flood plain). S37872 1-10 Ct 90 21 S37873 10-15 c2 97 17 S37874 15-20 Dt 114 10 Tanana silt loam: SE;iNW;i sec. 22, T. 1 S., R. 1 W. (modal) __ Alluvium (Flood plain). S37875 0-4 AI 52 60 S37876 4-12 c.~ 81 30 S37877 12-20 c.2 88 24 SE;iNE;i sec. 27, T. 1 N., R. 2 E. (more Alluvium. (Flood plain). S37878 0-272 A, 35 99 poorly drained). S37879 272-13 c1 I 98 19 S37880 13-20 c2 100 18 NE;iSW;i sec. 1, T. 1 S., R. 2 W. (lower in Alluvium (Flood plain). S37881 Q-3 AI 63 43 clay). S37882 3-11 Ct 99 20 S37883 21-30+ Ca 102 17 1 Tests performed by the Bureau of Public Roads in accordance with standard procedures of the American Association of State Highway Officials (1). 2 Based on Standard Specifications for Highway Materials and Methods of Sampling and Testing (Pt. 2, Ed. 8): The Moisture- density Relations of Soils Using 5.5-pound rammer and 12-in. drop, AASHO Designation T 99-57, Method A (1). 3 Mechanical analyses according to the American Association of State Highway ·Officials Designation T 88. Results by this pro- cedure frequently may differ somewhat from results that would have been obtained by the soil survey procedure of the Soil Con- servation Service (SCS). In the AASHO procedure, the fine mate- rial is analyzed by the hydrometer method and the various grain- size fractions are calculated on the basis of all the material, including t f FAIRBANKS AREA, ALASKA 33 test data 1 Mechanical analyses a Classification Percentage passing sieve-Percentage smaller than-Liquid Plastic- limit ity index AASH0 4 Unified 5 No.4 No. 10 No. 40 No. 200 2 in. %in. (4. 7 (2. 0 (0. 42 (0. 074 0. 05 0.02 0. 005 0.002 mm.) mm.) mm.) mm.) mm. mm. mm. mm. --·-·-!-------100 98 93 88 ---<-----------------------100 97 90 1-"" ·-------------·-100 99 93 "" ------------------·-100 96 92 ---1----7-------------·-100 98 93 -----------------·-100 99 94 -------------------100 99 96 93 -----------·-100 98 95 -------------------100 94 75 ------------1---------100 97 96 ---76-1-. -----100 76 52 100 18 12 9 4 3 ------1-" ·-----------------100 92 80 ------1-< ·-----------------100 97 89 --------------------------~ 100 65 38 ---+ ·-----------------100 79 56 1----------------100 14 8 100 95 74 67 60 8 5 ----·---------------100 98 85 81 ----------------·-100 93 87 ---------------------·-100 92 82 --------------------100 95 69 66 ------------------1-· 100 99 95 -----~ ------·----100 99 95 ------------·-100 97 90 87 ------------·-100 99 97 951 ------·---------100 99 94 that coarser than 2 millimeters in diameter. In the SCS soil sur- vey procedure, the fine material is analyzed by the pipette method and the material coarser than 2 millimeters in diameter is excluded from calculations of grain-size fractions. The mechanical analyses used in this table are not suitable for use in naming textura-l classes for soils. ' Based on Standard Specifications for Highway Materials and 51 17 10 46 7 A-5(9) _____ ML. 48 20 14 28 6 A-4(8) ___ ML-CL. 45 12 5 27 4 A-4(8)_ --ML-CL. 55 18 11 38 7 A-4(8) ___ ML. 54 22 16 30 6 A-4(8) --ML-CL. 55 19 12 30 6 A-4(8) ___ ML. 60 18 11 41 6 A-5(8) -ML. 60 19 12 32 6 A-4(8) ML. 26 8 5 (•) (•) A-4E8) ML. 69 23 12 50 9 A-5(10) ____ ML. 16 5 2 (•) (6) A-4(8) _____ ML. 2 1 0 (6) (6) A-1-a(O) --_ GP. 33 7 5 (6) (6) A-4(8) -----ML. 40 4 2 (•) (6) A-4(8) _____ ML. 11 4 1 (6) (6) A-4(6) _____ ML. 19 5 1 (6) (6) A-4(8) _____ ML. 4 1 1 (6) (6) A-2-4(0) __ SM. 4 3 1 (6) (6) A-3(0) _____ SP-SM. 66 36 18 96 20 A-7-5(16) OH. 65 35 19 48 6 A-5(10) ML. 39 12 5 37 6 A-4(8) __ ML. 46 11 6 (6) (6) A-4(7) OL. 55 19 12 31 5 A-4(8) _____ ML. 54 16 12 30 5 A-4(8) ML. 66 28 17 64 11 A-7-5(12) __ MH. 66 23 13 34 8 A-4(8) -----ML. 55 18 10 29 5 A-4(8)_ ----ML-CL. Methods of Sampling and Testing (Pt. 1, Ed. 8): The Classifica- tion of Soils and Soil-Aggregate Mixtures for Highway Construction Purposes, AASHO Designation M 1.45-49 (1). 5 Based on the Unified Soil Classification Syste!Il, Tech. Memo. No. 3-357, v. 1, Waterways Expt. Sta. Corps of Eng., March 1953 (13). 6 Nonplastic. 34 SOIL SURVEY SERIES 19591 NO. 25 Formation, Classification, and Morphology of the Soils Soil properties are strongly influenced .by climate- temperature and the amount, kind, and distribution of precipitation. Temperature and precipitation character- istics also determine, to a considerable extent, the kind of vegetation that will grow in an area. This vegetation, in turn, profoundly influences soil characteristics. The ex- tent that soil material or parent rock has been changed by climatic and biologic forces depends, in large part, on the length of time that these soil-forming processes have been active. Local variations in topography also affect the na- ture and intensity of soil development. For example, soils formed in low areas having a permanently high water table may be very different from those that formed on well-drained uplands. Factors of Soil Formation Soils of the Fairbanks Area have formed in two differ- ent, but related, parent materials. Those on the uplands have formed in micaceous loess derived from glacial out- wash. Those on the alluvial plains have formed either in water-deposited, micaceous sand and silt that was derived primarily from glaciers, or in silty material that has washed from nearby hillsides. Some depressions in the alluvial plains contain peat soils. The Fairbanks Area has a continental climate character- ized by long, cold winters and short, warm summers. The total annual precipitation is only about 12 inches, about half of which falls as rain in the short summer season. Most of this is retained if the soil is covered by native veg- . etation. Uncultivated, well-drained soils are generally moist throughout the summer but may be dry if the rain- fall is exceptionally lo"·· Other soils are moist or wet all summer. The soils in most cleared fields, however, are deficient in moisture part of the time. Topographic position and aspect greatly influence the drainage characteristics of soils in the Fairbanks Area. In the uplands, the north-facing slopes receive much less solar heat than the south-facing slopes. As a result, the soil on north-facing slopes is generally underlain by per- mafrost and is always cold and wet. In contrast, most of the soil on south-facing slopes is not perennially frozen, and it is well drained or moderately well drained. In the broad, low areas of the alluvial plains, the soil has a high permafrost table and is poorly drained. On slightly higher ground on the plains, the soil has a deeper penna- frost table and is imperfectly drained. On levees along rivers, permafrost is deep or absent, and the soil is well drained. All 'Yell drained and most moderately well drained soils in the Area have formed under a boreal forest dominated by white spruce, paper birch, and quaking aspen. The imperfectly drained soils support a poor growth of these trees, mixed with black spruce, tamarack, and willow. The ground is covered by a dense growth of moss and low · shrubs. The poorly drained and very poorly drained soils support a sparse tree conr consisting mainly of black spruce. They have a ground cover of mosses, shrubs, and sedge tussocks. Additional information regarding the vegetation of the Fairbanks Area is given in the section "Vegetation.~' The Fairbanks Area has never been glaciated, but it is likely that all soils in the Area have developed since the time of maximum glacial advance in the mountains to the south. Only well-drained soils of the uplands, on which loess is no longer being deposited, can be considered to be mature. Soils forming in the very recent deposits of the alluvial plains are young and have not had time for hori- zon differentiation. The poorly drained soils on both uplands and alluvial plains show little development of horizons. Classification and Morphology Soils are classified on the basis of profile characteristics into categories that are progressively more inclusive. The lowest categories commonly used in the field-series, type, and phase-are discussed in the section "How Soils Are Named, Mapped, and Classified." In a higher category of classification are great soil groups. Each great soil group contains many soils that have common characteris- tics developed as a result of environmental influences. The 11 soil series identified in the Fairbanks Area have been placed in 5 great soil groups as follows. Great soil group and series: Subarctic Brown Forest soils: Fairbanks Gilmore Minto Alluvial soils : Chena Salchalret Low-Humic Gley soils: Bradway Tanana Ester' Goldstream' Saulich' Bog soils: Lemeta· 1 Intergrading to Bog soils. The characteristics of the soils in each great soil group are described in the following pages. Subarctic Brown Forest soils Soils of the Fairbanks, Gilmore, and Minto series are Subarctic Brown Forest soils. The Minto soils are only moderately well drained and have some of the characteristics of the Low-Humic Glev soils. The Subarctic Brown Forest soils have developed under forest in the Fairbanks Area and other subarctic regions. These areas have a continental climate characterized by low annual precipitation; short, warm summers; and long, cold winters. The soils are well drained and have fairly thin accumulation of litter and mosses on the surface. These accumulations are underlain by brown surface soil and subsoil. The soils are generally medi urn to strongly acid and may have a weakly bleached layer below the surface ho_rizon.-Base saturation is high. !he. subsoil may contam tlun, wavy bands of matenal lugh m clay. Structural development is weak. · FAIRBANKS SERIES Soils of the Fairbanks series are believed to be mature representatives of the Subarctic Brown Forest group. These soils occur principally on southerly slopes of hills FAIRBANKS ·AREA, ALASKA 35 and have developed in micaceous loess. The sources o:f the loess are outwash plains and flood plains o:f streams carry- ing glacial outwash material ( 8). It is not likely that ther~ have been additions o:f loess in substantial amounts since the last major retreat o:f the glaciers. Consequently, soil :formation and horizon differentiation have been progressing :for a long time without interruption. Typical profile o:f Fairbanks silt loam (undisturbed) (SE~SW~4 sec.18, T. 1 N., R.l E., Fairbanks meridiah) : A00 27~ to 2 inches, litter of leaves and twigs. A0 2 inches to 0, dark reddish-brown (5YR 2/2) mat; pieces of charcoal; mycelia; slightly acid; abrupt, smooth boundary. A 1 0 to 4 inches, dark yellowish-brown (10YR 3/4) silt loam; weak, very fine, crumb structure; very friable; many roots; slightly acid; abrupt, wavy boundary. A 2(?) 4 to 7 inches, grayish-brown (10YR 5/2) silt; very weak, very thin, platy structure breaking to granular structure when crushed; very friable; few roots; strongly acid; abrupt, wavy boundary. B 21 7 to 17 inches, dark grayish-brown (lOYR 4/2) silt loam; moderate, very thin, platy structure; roughly horizontal, undulating bands of dark yellowish- brown (10YR 4/3) fine silt loam or silty clay loam, 7;1 inch thick, occur at vertical intervals of 4 or 5 inches in this and the B 22 horizon; very friable; very few roots; strongly acid; gradual boundary. B 22 17 to 26 inches, dark grayish-brown (10YR 4/2) to grayish-brown (10YR 5/2) silt loam; moderate, very thin, platy structure; very friable; very few roots; medium acid; gradual boundary. . cl 26 to 38 inches, dark grayish-brown (2o5Y 4/2) Rilt; few, small mottles of brown; moderate, very thin, platy structure; some plate faces slightly darker than bulk of horizon; very friable; almost no roots; slightly acid; gradual boundary. c2 38 to 48 inches +, olive-gray (5Y 4/2, 5/2) Hilt; brown mottles more prominent thaD in C1 horizon; \'Pry friable; no roots; slightly acid. Results o:f analyses o:f samples :from this profile are shown in table 9. The thin bands o:f fine material in the subsoil are an outstanding characteristic o:f the Fairbanks soils. These bands are roughly horizontal, but they undulate through the B horizon and are usually interconnected. In places they may be as much as hal:f an inch thick, but normally they are much thinner. The upper and lo,Yer boundaries o:f the bands are very abrupt. Woithin the bands, the soil is arranged in fine blocks, commonly 'Yith :faint clay films on the peds. Most o:f the clay accumulation in the B hori- zon that is indicated by the particle-size analysis in table 9 is in these bands. The texture o:f the bulk o:f the B horizon differs little :from that o:f horizons above and below it. TABLE 9.-Physical and chemical propertie8 of a profile of Fairbank8 silt loam [Analyses by Soil Survey Laboratory, Lincoln, Nebr.] . PHYSICAL PROPERTIES Particle-size distribution Moisture held at tension of- Depth Very from Horizon Very Coarse Medium Fine fine Silt Clay Textural class surface coarse sand sand sand sand (0.05-(less ?lo Ya 15 sand (1-0o5 (0.5-(Oo25-(001-0.002 than atmos- atmos-atmos- (2-1 mm.) 0.25 Oo1 Oo 05 mmo) Oo002 ph ere ph ere pherEs mm.) mmo) mmo) mm.) mmo) Inches Percent Percent Percent Percent Percent Percent Percent Percent Percent Percent 0-4 AI Oo 3 Oo 8 Oo 6 1.9 8o 6 780 0 9. 8 Silt loam _________ 6504 360 0 120 0 4-7 A2 . 1 02 02 .8 100 4 800 5 7. 8 Silt ______________ 350 4 20. 5 40 7 7-17 B21 . 1 . 2 . 2 . 07 100 7 740 9 130 2 Silt loam _________ 350 0 170 7 60 1 17-26 B22 --------. 1 .2 o8 8. 6 780 1 120 2 Silt loam ________ . 35. 7 21.3 5. 9 26-38 c1 --------0 1 0 1 .7 100 3 81.8 7. 0 Silt ______________ 35. 8 18. 2 4. 7 38--48 c2 --------0 1 02 07 11. 7 820 4 4. 9 Silt_ _____________ 370 5 17. 7 4o 1 CHEMICAL PROPERTIES Reaction Carbon-Free Exchangeable cations (milliequivalents Calcium- Depth in 1:1 Organic Nitro-nitro-iron per 100 grams of soil) Base magne- from Horizon soil-water carbon gen gen oxide satura-sium surface suspen-ratio (Fe20a) tion ratio sion Ca Mg Na K H Sum --------- Inches pH Percent Percent Percent Percent 0-4 At I 6. 3 4. 67 Oo 225 200 8 1.7 200 6 4. 1 ------Oo 4 80 1 33. 2 76 5o 0 4-7 A2 5. 5 0 68 . 041 16. 6 1.5 6o 5 3o 2 ------02 4o 0 13. ll 71 2. 0 7-17 B21 5o 3 0 38 . 028 130 6 1.8 60 2 40 6 0. 1 .2 20 8 13. 9 80 1.8 17-26 B22 5o 6 . 29 0 026 11. 2 1.8 5o 5 5o 8 0 1 02 20 4 14. 0 83 oB 26-38 c1 60 1 . 29 . 028 10. 4 1.4 5o 2 5. 2 .2 .2 20 0 120 8 84 1.0 38-48 c2 6. 4 0 32 0 029 11. 0 1.3 5. 0 30 9 .2 . 1 1.2 10. 4 88 1.3 1 pH in 1: 5 soil-water suspension. 36 SOIL SURVEY SERIES 1 9 59, NO. 2 5 The mechanism of movement and deposition of the clay is uncertain, but the bands are believed to be the result of clay movement within the soil. The bands can be con- sidered, therefore, to be an early stage in the development of a textural B horizon. The presence of a thin, slightly bleached zone above the thicker bands in many profiles indicates that the bands restrict percolation and that water moves laterally in the soil above them. In the A 2 , B 21 , and B 22 horizons, colors of the vertical plate edges, when dry, are darker by one step in value than the horizontal plate surfaces. The clay minerals in the Fairbanks soils consist of mixed-layer montmorillonite-vermiculite, some mica, and a trace of kaolinite. Mica is dominant in the parent loess, and there is little of the mixed-layer material.4 Some leaching of cations has taken place in the develop- ment of the Fairbanks soils, but base saturation remains fairly high. There is evidence of movement of free iron from the surface soil to the subsoil, accompanied probably by small quantities of organic matter, but the degree of podzolization is slight. As the Fairbanks soils undergo further development, they will probably become more acid, but it is unlikely they will develop toward Podzols. GILMORE SERIES The Gilmore soils are similar to the Fairbanks soils but have developed in shallower loess. Bedrock, rather than the parent loess, underlies these soils. In some places, the upper part of the underlying schist has been modified by soil-forming processes. Profile of a relatively deep, m1disturbed Gilmore silt loam (about 12 miles west of the Fairbanks Area, near the top of a high ridge in Bonanza Creek Experimental Forest): D 4% to 3 inches, mat of moss and forest litter. 3 inches to 1 inch, very dark brown (10YR 2/2) mat of roots, moss, and partially decomposed organic mate- rial; mycelia; slightly acid. 1 inch to 0, very dark brown (10YR 2/2) well-decomposed organic matter; fewer mycelia than in horizon above; heavier concentration of roots than in lower horizon; medium acid; abrupt, smooth boundary. 0 to 2 inches, very dark grayish-brown (10YR 3/2) silt loam; very weak, very thin, platy structure breaking easily to weak, very fine granules; very friable; roots plentiful; strongly acid; clear, smooth boundary. 2 to 5 inches, brown (10YR 5/3) silt loam; weak, very thin, platy structure; very friable; roots plentiful; few angular pebbles of schist in this and lower horizons; strongly acid; clear, wavy bdundary. 5 to 8 inches, dark-brown (10YR 4/3) silt loam; moderate, very thin, platy structure; very friable; roots plenti- ful; lowest H inch in this horizon is somewhat lighter· in color than upper part; strongly acid; abrupt, wavy boundary. 8 to 87~ incheE, thin band, roughly horizontal, of dark- brown (10YR 3/3) fine silt loam or silty clay loam; moderate, very fine, subangular blocky &tructure; faint clay films on peds; friable; very strongly acid; abrupt, wavy boundary. (This band is undulating and in places is divided into several thinner bands.) 8X to 17 inches, dark grayish-brown (10YR 4/2) silt loam; moderate, vm;y thin, platy structure; very friable; roots plentiful to few; very thin, irregular band of fine silt loam in middle of horizon; strongly acid; abrupt, wavy boundary. 17 to 24 inches +, weathered mica schist; slightlyacid. 4 Analyses by HsiN-YUAN Tu, Soil Survey Laboratories, SCS, Beltsville, Md. Profile of a shallower Gilmore silt loam in a burned area of aspen forest (near the center of section 15, T. 1 N., R. 1 W., Fairbanks meridian): Aoo and A.o 1 inch to 0, brown mat of partially decomposed forest litter. A 1 0 to 3 inches, reddish-brown (5YR 4/3) silt loam near top of horizon to dark-brown (10YR 4/3) silt loam near bottom of horizon; weak, very thin, platy structure; friable; clear, smooth boundary. A2 3 to 5 inches, brown (10YR 5/3) silt loam; moderate, very thin, platy structure; friable; clear, wavy boundary. B 2 5 to 9 inches, dark-brown (7.5YR 4/4) silt loam; moderate, very thin, platy structure; color on plate faces is one value step lighter than on plate edges; friable; clear, wavy boundary. B 3 and D 9 inches +, yellowish-brown (10YR 5/6) gravelly sandy loam; many platy fragments; grades into hard schist rock. Bands of finer material have not developed in this profile. MINTO SER~S The Minto series consists of moderately well drained soils on colluvial slopes near the bases of ridges. The soils have characteristics that are intermediate between those of the Subarctic Brown Forest soils and the Low-Humic Gley soils. The Minto soils are always wetter than the Fairbanks soils. In addition, they are grayer throughout the profile and have mottled subsoil. There has ap- parently been no movement of clay within the profile; bands of fine material are not evident. Profile of Minto silt loam (undisturbed) on a long · slope of 3 percent (about 3 miles east of the Little Chena River Bridge on the Chena-Hot Springs Road) : Aoo 4 to 3 inches, relatively unweathered mat of roots, moss, and forest litter; abrupt, smooth boundary. A.o 3 inches to 0, dark reddish-brown (5YR 2/2) mat of roots and partially decomposed organic material; many mycelia; extremely acid; abrupt, smooth boundary. A1 0 to 3 inches, very dark grayish-brown (10YR 3/2) silt loam; weak, fine, granular structure; friable; roots plentiful; charcoal particles throughout horizon but mostly near the surface; very strongly acid; clear, wavy boundary. B (?) 3 to 7 inches, dark grayish-brown (2.5Y 4/2) silt loam; many, large, distinct mottles of dark yellowish brown and a few, dark streaks along old root channels near top of horizon; mottles have dif- fuse boundaries; weak, medium, subangular blocky structure breaking to very weak, very thin plates; many fine spherical pellets of silt loam, less than 2 millimeters in diameter, that crush to same color as matrix; very friable; few roots; strongly acid; clear, wavy boundary. C 1 7 to 15 inches, dark grayish-brown (2.5Y 4/2) silt loam; few, medium, faint mottles of olive brown; moder- ate, very thin, platy structure; very friable; few roots; slightly acid; gradual boundary. C 2 15 to 30 inches +, dark grayish-brown (2.5Y 4/2) silt; many horizontal streaks of olive brown; moderate, very thin, platy structure; very friable; roots few or absent; mildly alkaline. The Minto soils are not underlain by a continuous layer of permafrost, as are the adjoining silty soils of the alluvi- al plains. However, underground masses of ice or wedges of ice in a polygonal pattern occur sporadically at a depth of 4 feet or more. Removal of the insulating mat of organic material from the soil surface through clearing or by forest fire results in higher soil temperatures and the eventual melting of this underground ice. Subterranean cavities are thus formed. They are enlarged by ground FAIRBANKS AREA, ALASKA 37 water and e:rlended through tunneling, or piping, to other parts of the field. In time, the layer of soil above the cavities collapses and forms deep, steep-walled pits or an irregular, hummocky microrelief. As a rule, these thermokarst mounds and pits do not appear for 8 to 10 years after clearing. However, uneven subsidence begins in some fields only 2 to 3 years after clearing. In other fields, as much as 30 years may elapse before thermokarst pitting becomes evident. These phenomena occur mainly on colluvial slopes where buried, discontinuous masses of underground ice exist. Tunneling may occasionally extend up the slope to adjoin- ing areas of moderately sloping Fairbanks soils. Pewe ( 7) has published a detailed description of thermokarst phenomena in cultivated fields. Alluvial soils Soils of the Salchaket and Chena series are Alluvial soils. They are well-drained and excessively drained soils on alluvial plains along the main rivers. They are form- ing from recent alluvium, which has been altered only slightly by soil-forming processes. SALCHAKET SERIES The Salchaket soils consist of stratified sandy and silty material over a substratum of water-laid gravel. Sandy material is dominant in most profiles, but a thin, silty surface layer is common. Depth to gravel varies greatly, even within short distances. It may range from as little as 10 inches to more than 6 feet. The native vegetation on Salchaket soils is essentially the same kind of white spruce-birch forest under wh1ch the Subarctic Brown Forest soils have developed. Profile of a moderately deep, undisturbed Salchaket very fine sandy loam (NE:L4NW:L4 sec. 19, T. 1 S., R. 2 E., Fairbanks meridian) : ~ 7 inches to 0, mat of moss, roots, and partially decomposed organic material; mycelia; very strongly acid; abrupt, smooth boundary. 0 to 3 inches, mixed olive-brown (2.5Y 4/4) and grayish- brown (2.5Y 5/2) silt loam; black lenses of highly decomposed organic matter, as much as 1 inch thick, especially near base of horizon; weak, medium, granular structure; very friable; roots plentiful; very strongly acid; abrupt, smooth boundary. 3 to 10 inches, mixed gray (10YR 6/1) and brown (7.5YR 4/4) very fine sandy loam; few black lenses, like those in horizon above; very weak, medium, subangular blocky structure; very friable; roots plentiful; slightly acid; abrupt, smooth boundary. 10 to 26 inches, gray (10YR 5/1) fine sand; common, medium, distinct mottles of strong brown; very thin, slightly browner horizontal layers a few millimeters apart; structureless; loose; few roots; mildly alkaline; abrupt, smooth boundary. 26 inches +, gravel and coarse sand; all pebbles rounded; most have diameters of less than 1 inch, but some are as large as 3 inches; many feet thick. In many places, thin silty lenses are in the profile. These commonly stay frozen in spring and early summer, long after the sandy strata have thawed. Permafrost is deep or absent. The Salchaket soils generally have a mottled appear- ance. This color variegation is believed to be an early stage in the development of horizons that are similar to those in the Subarctic Brown Forest soils. It is not believed that the mottles indicate poor drainage. It is possible, however, that the mottling originated during an earlier period of poor or imperfect drainage. CHEN A SERIES The Chena series consists of shallow, excessively drained soils made up of less th!Ln 10 inches of stratified ma,terial over alluvial gravel. The soils are mainly sandy, but thin silty strata may occur. Profile of Chena very fine sandy loam (undisturbed) (NW:L4SE:L4 sec. 28, T. 2 ~., R. 3 E., Fairbanks meridian) : A00 and A0 2~ inches to 0, dark reddish-brown (5YR 2/2) mat of roots and partially decomposed organic material; very thin layer of undecomposed leaves and needles; mycelia; very strongly acid; abrupt, smooth boundary. A1 0 to 1 inch, very dark grayish-brown (10YR 3/2) and dark grayish-brown (10YR 4/2) silt loam; weak, very fine, granular structure; friable; many roots; very strongly acid; abrupt, smooth boundary. A3 1 to 4 inches, dark yellowish-brown (10YR 4/4) very fine sandy loam; very weak, fine, subangular blocky struc- ture; very friable; few roots; medium acid; abrupt, wavy boundary. C 4 to 7 inches, grayish-brown (10YR 5/2) fine sand grading to light brownish gray (10YR 6/2) with depth; few yellowish-brown streaks along old root channels; single grain; loose; few roots; slightly acid; abrupt, wavy boundary. D 7 to 18 inches +, gravel and coarse sand; single grain; loose; all gravel rounded; few pebbles more than 3 inches in diameter; many feet thick. Low-Humic Gley soils Soils of the Tanana, Bradway, Ester, Goldstream, and Saulich series are Low-Humic Gley soils. The last three series named are intergrades to Bog soils. The Low-Humic Gley great soil group consists of imperfectly drained and poorly drained soils that have thin, organic surface horizons and highly mottled mineral horizons. There is no textural differentiation resulting from soil-forming processes. Many profiles, however, have textural stratification because the soils are composed of alluvial material. Under the native vegetation., Low- Humic Gley soils in the Fairbanks Area are underlain by permafrost. After clearing and subsequent warming of the soil, the depth to the permafrost table increases from less than 3 feet to more than 6 feet. As a result, internal drainage of the soil is improved. Some soils in areas that have been cleared for many years become somewhat browner than when under the native vegetation. Low-Humic Gley soils that intergrade toward Bog soils are those of the Ester, Goldstream, and Saulich series. These soils have thin, dark A horizons over gray or mottled B or C horizons comparable to those of typical Low-Humic Gleys. They are, however, covered with a surface layer of sphagnum moss, roots, or a mixture of these, that ranges from 5 to 13 inches in thickness. TANANA SERIES The Tanana series consists of imperfectly drained soils of the alluvial plains. These soils are dominantly silty but may contain lenses of sand at any depth. The native vegetation is forest consisting of scrubby black spruce, white spruce, birch, tamarack, and willow. Under the trees is a ground cover consisting of moss and shrubs. The soil is perennially frozen to within 30 inches of the sur- face, and it is always wet above the permafrost. 38 SOIL SURVEY SERIES 1959, NO. 25 Typical profile of Tanana silt loam (undisturbed) (SE1,4NW1,4 sec. 22, T. 1 S., R. 1 W., Fairbanks meridian): A00 and Ao 5 inches to 0, dark-brown (7.5YR 3/2) mat of roots, moss, and lichen; color grades to black (10YR 2/1) at bottom of horizon; mycelia; strongly acid; abrupt, smooth boundary. A1 0 to 4 inches, olive-gray (5Y 4/2) silt loam; many large patches of grayish brown (2.5Y 5/2); many streaks and patches of black (10YR 2/1); the maxi- mum number of-black streaks are in this horizon, but similar streaks occur throughout the profile in an irregular pattern; massive; friable; roots plentiful; neutral; clear, irregular boundary. C, 4 to 20 inches, olive-brown (2.5Y 4/4) silt loam; streaks and patches of black and grayish brown; few, medium, distinct mottles of dark brown; few smooth concretions of brown; massive; friable when moist, nonsticky when wet; few roots; mildly alkaline; frozen at depth of 20 inches (Sept. 3, 1958); 3 to 10 feet thick over gravelly substratum. Results of analyses of samples from this profile are shown in table 10. . The upper and lower parts of the Cg horizon were sampled separately. Many coarse particles are concretions, probably of iron or iron and manganese. Streamcdeposited gravel underlies most areas of Tanana silt loam, but it seldom occurs in the upper 4 feet of the profile. Underground ice is continuous in the Tanana soils. Consequently, thermokarst pits do not form after vegetation has been cleared and the soil has thawed to a greater depth. As a rule, however, there is a slight general subsidence in cleared areas. Except for an accumulation of acid organic matter, especially in the upper part of the profile, the parent material has been altered but little. The mineral soil is neutral to mildly alkaline, and base saturation is high. BRADWAY SERIES The Bradway soils are poorly drained, sandy members of the Low-Humic Gley group. In texture they are sim- ilar to the well-drained Salchaket soils, but they occupy lower areas in old stream channels in the alluvial plains. Under the native forest of black spruce or under the dense growth of sedge or grasses, the soil is perennially frozen below a depth of 36 inches, and it is always wet above the permafrost. The water table is at a depth of 18 inches or less. Profile of Bradway very fine sandy loam (SW1,4SW1,4 sec. 23, T. 1 S., R. 1 E., Fairbanks meridian, m a severely burned area) : Ao 4 inches to 0, black (5YR 2/1) mat of roots, moss, partly decomposed organic material, and charcoal; slight admixture of silt; medium acid; horizon may be as much as 12 inches thick. A1 0 to 2 inches, black (5YR 2/1), mucky silt loam; weak, fine, gr~tnular structure; friable; roots plentiful; slightly acid; abrupt, wavy boundary. c. 2 to 36 inches, dark-gray (N 4/0) very fine sandy loam; many, large, prominent mottles of dark brown; thin lenses of silt loam and fine sand, mostly below 24 inches; weak, thin, platy structure; very friable; few roots; mildly alkaline; water table at 18 inches; frozen at depth of 36 inches (Aug. 30, 1959). In many places, the lower part of the soil is more highly gleyed than the upper part and has a greenish or bluish color. Gravel underlies the Bradway soils at a depth of more than 4 feet. TABLE 10.-Physical and chemical prope1•ties of a profile of Tanana silt loam [Analyses by Soil Survey Laboratory, Lincoln, Nebr.] PHYSICAL PROPERTIES Particle-size distribution Depth from Horizon Textural surface Very coarse Coarse sand Medium sand Fine sand Very fine Silt (0.05-Clay (less class sand (1-0.5 mm.) (0.5-0.25 (0.25-0.1 sand (0.1-0.002 mm.) than 0.002 (2-1 mm.) mm.) mm.) 0.05 mm.) mm.) Inches Percent Percent Percent Percent Percent Percent Percent 5-0 Aoo ------------------------------------------------------------------------------------------------D-4 AI 0. 2 2. 2 1.6 3. 7 9. 1 64. 6 18. 6 Silt loam. 4-12 c.~ .2 . 4 .3 2. 2 18. 9 64. 1 13. 9 Silt loam . 12-20 c., 0 1 . 3 0 2 1.9 17. 3 67. 3 12. 9 Silt loam. · .. CHEMICAL PROPERTIES I Horizon Reaction Carbon-Free Exchangeable cations (milliequivalents Depth in 1:1 Organic Nitro-nitro-iron per 100 grams of soil) Base Calcium- from soil-water carbon gen gen oxide saturation magnesium surface suspen-ratio (Fe,03) ratio sion Ca Mg Na K H Sum --------- Inches pH Percent Percent Percent Percent Percent 5-0 Aoo 15.4 41. 12 1. 086 37. 9 -------------- ------------ ------ --------------------------------0-4 AI 7. 1 16. 61 0 632 26. 3 1. 8 67. 4 10. 5 0. 2 0. 4 14. 8 93. 3 84 6. 4 4-12 c.~ 7. 4 5. 07 . 217 23. 4 1. 9 29. 3 3. 1 .1 .3 5. 2 38. 0 86 9. 4 12-20 c., 7. 7 2. 89 0 141 20. 5 1.7 24. 2 2. 0 0 1 0 3 2. 8 29. 4 90 12. 1 I pH in 1:3 soil-water suspension. FAIRBANKS AREA, ALASKA 39 ESTER SERIES The Ester series consists of shallow soils on steep, north- facing slopes near the tops of ridges. The Ester soils probably receive the least insolation of any of the soils of the Area. The lower part of the mat of moss on the sur- face may be frozen throughout the summer. A sparse forest of spindly black spruce covers most areas, but in many places this gives way to a dense cover of shrubs. Where intense fires have destroyed the mat of moss, the soil supports a stand of paJ?er birch. The Ester soils commonly adjoin the well-dramed Gilmore and Fairbanks soils, which occupy the south slopes of the same ridge (2). Profile of Ester silt loam (undisturbed) (west of the Fairbariks Area, about 12 miles from Ester in Bonanza Creek Experimental Forest) : · 13 to 10 inches, live sphagnum moss. Ao 10 inches to 0, slightly decomposed sphagnum moss; few mycelia; many roots of higher plants; extremely acid; abrupt, smooth boundary. A1 0 to 4 inches, very dark grayish-brown (2.5Y 3/2), mica- ceous silt loam; lenses and pockets of black (N 2/0), · highly decomposed organic matter; few roots; very strongly acid; frozen (Sept. 20, 1958); abrupt, wavy boundary. c. 4 to 10 inches+, olive-gray (5Y 4/2), micaceous silt loam; common, large, distinct mottles of olive brown; many streaks of black and dark brown; roots few or absent; frozen; underlying, weathered schist is at a depth of approximately 18 inches; strongly acid. The thickness of the loess mantle over bedrock ranges from less than 10 inches to about 24 inches. " GOLDSTREAM SERIES The Goldstream soils are silty, but they are somewhat finer than other soils of the Fairbanks Area. They have formed from alluvium deposited by slo:wly moving water and, in upland drainageways, from fine colluvial material derived from loess. Sandy lenses may occur in the pro- file, especially near large streams. For the most part, however, the Goldstream soils are silty throughout, and gravel is many feet below the surface. These soils are generally free o£ trees, but spindly black spruce, tamarack, and willow occur in places. They support a cover of low shrubs. The soil surface characteristically is very hum- mocky because of numerous closely spaced tussocks of sedge. Profile of Goldstream silt loam (undisturbed) on the alluvial plains (NE1j4 S\V"1,4 sec. 35, T. 1 N., R. 1 W., Fair- banks meridian) : · Aoo and Ao 5 inches to 0, mat of moss and roots; moss is undecomposed in upper part of horizon but black in lower part; strongly acid; clear, wavy boundary. A, 0 to 4 inches, black (N 2/0 and 5Y 2/1) silt loam; weak, fine, subangular blocky structure; slightly sticky; many roots; strongly acid; clear, wavy boundary. c. 4 to 19 inches, gray (5Y 5/1) silt loam; many, large, distinct mottles of olive brown and few irregular streaks of black; massive; sticky; few roots; neutral; frozen at depth of 19 inches (Aug. 28, 1959). Under native vegetation, the depth to permafrost is seldom more than 24 inches and the water table is near the surface. The permafrost table is at a lower depth after removal of the moss cover, but the water table stays high unless artificial drainage is established. SAULICH SERIES The Saulich soils are on north-facing slopes in positions that are comparable to those of the Mmto soils on south- facing slopes, although generally steeper. Saulich soils are on lower slopes, are deeper, and thaw to somewhat greater depths than the Ester soils. Representative. profile of Saulich silt loam (undis- turbed) (SW1,4SW1,4 sec. 7, T. 1 N., R. 1 E., Fairbanks meridian): Aoo and Ao 7 inches to 0, dark-brown (7.5YR 4/4, moist) to light-brown (7.5YR 6/4, squeezed dry) mat of moss and roots; mycelia in lower part; extremely acid; abrupt, smooth boundary. A, 0 to 4 inches, dark olive-gray (5Y 3/2) silt loam with black (5Y 2/1) streaks; very weak, very thin, platy structure; very friable when moist, nonsticky when wet; roots plentiful; very strongly acid; clear, wavy boundary. A3 4 to 7 inches, dark grayish-brown (2.5Y 4/2) and very dark grayish-brown (2.5Y 3/2) silt loam; few, thin, black streaks; weak, very thin, platy structure; very friable when moist, nonsticky when wet; few roots; strongly acid; clear, wavy boundary. c. 7 to 15 inches, dark grayish-brown (2.5Y 4/2) silt loam; many, medi~m, faint mottles of olive brown, elongated horizontally; few streaks of black; weak, very thin, platy structure; very friable when moist, nonsticky when wet; few roots; medium acid; frozen at depth of 15 inches (Aug. 30, 1959); 3 feet to many feet in thickness. The permafrost table in Saulich soils is generally at a depth between 12 and 30 inches. Where the natural cover of moss has been removed, however, the soil thaws to greater depths. Seep water from the higher lying Ester soils on the same slopes adds to the wetness of these soils. The additional moisture makes conditions favorable for the growth of a mossy mat, which insulates the soil and helps preserve the permafrost. Bog soils Bog soils have formed in organic material. Soils of the Lemeta series belong to the Bog great soil group. LEllfETA SERIES The Lemeta soils consist mainly of peat formed from undecomposed sphagnum moss in which there are layers of peat formed from sedge. The peat is perennially frozen below a depth of 1 to 21fz feet. The water table is always just below the surface. Living vegetation is essentially the same as that on the Low-Humic Gley soils intergrading to Bog soils. A polygonal ground pattern has developed in many areas of these soils. Profile of Lemeta peat (undisturbed) (N\V"1,4SW1,4 sec. 32, T.1 N., R. 1 W., Fairbanks meridian) : 0 to 13 inches, dark-brown (7.5YR 4/4, moist) to light-brown (7.5YR 6/4, squeezed dry) moss peat, arranged in thin, horizontal layers; upper few inches consist of living moss; few, very thin layers of black (N 2/0) sedge peat; many roots of higher plants, especially in upper 3 inches ; strongly acid. . 13 to 25 inches, moss peat, like that in horizon above but with many, roughly horizontal layers of black sedge peat; very strongly acid; frozen at a depth of 25 inches (Aug. 28, 1959). Lemeta peat has accumulated in shallow lakes on the alluvial plains. Remnants of these lakes occur in several bogs. In other bogs, cave-in lakes have formed in con- nection with polygonal ground development. · 40 SOIL SURVEY SERIES 1959, NO. 25 Literature Cited (1) AMERICAN AssociATION oF STATE HIGHWAY OFFICIALS. (2) (3) (4) {5) (6) (7) 1961. STANDARD SPECIFICATIONS FOR HIGHWAY MA- TERIALS AND METHODS 01' SAMPLING AND TESTING. Ed. 8, 2 parts, illus. KRAusE, H. H., RIEGER, S., and WILDE, S. S. 1959. SOILS AND l'OREST GROWTH ON DIFFERENT ASPECTS IN THE TANANA WATERSHED OF IN- TERIOR ALASKA. Ecology 40 : 492-495, ill us. LINDHOLM, G. F., THOMAS, L.A., DAVIDSON, D. T., and OTHERS. 1959. SILTS NEAR BIG DELTA AND FAIRBANKS. In the Geology and Engineering character- istics of some Alaskan Soils, Iowa State Univ. Bul. No. 186, pp. 33-70, illus. LuTz, H. J. 1956. ECOLOGICAL EFFECTS OF FOREST FIRES IN THE INTERIOR OF ALASKA. U.S. Dept. Agr. Tech. Bul. No. 1133, 121 pp., ill us. MERTIE, J. B. JR. 1937. THE YUKON-TANANA REGION, ALASKA. U.S. ' Geol. Survey Bul. 872, 276 pp., illus. MrcK,A. H. 1957. ARCTIC AND SUBARCTIC AGRICULTURE. Bi- ology Colloquim Proc. 18: 100-109, illus. Corvallis, Ore. P:E-wE,T.L. 1954. EFECT OF PERMAFROST ON CULTIVATED FIELDS, FAIRBANKS AREA, ALASKA. In Mineral Re- sources of Alaska 1951-53, Geol. Survey Bul. 989, pp. 315-351. {8) 1955. ORIGIN 01' 'l'HE UPLAND SILT NEAR FAIRBANKS, ALASKA. Geol. Soc. Amer. Bul. 66: 699- 724, illus. {9) -- (10) (11) (12) (13) (14) (15) 1958. GEOLOGY OF THE FAIRBANKS (D-2) QUADRAN- GLE, ALASKA. U.S. Geol. Survey Geol. Quad. Map GQ-110. SoiL SURVEY STAFF. 1951. SOIL SURVEY MANUAL. U.S. Dept. Agr. Handbook No. 18, 503 pp., ill us. TIIORNTHW AITE, C. S. 1931. THE CLIMATES OF NORTH Al\IERICA ACCORDING TO A NEW CLASSIFICATION. Geog. Rev. 21 : 633-655, illus. uNIVERSITY OF ALASKA. 1958. FERTU.IZERS FOR ALASKA, 1958 AND 1959. Univ. of Alaska, Agri. Ext. Serv., Circ. 513,2 pp. (Revised.) WATERWAYS ExPERIMENT STATION. 1953. UNIFIED SOIL CLASSIFICATION SYSTEM. Corps of Eng., U.S. Army Tech. Memo. No. 3- 357, V. 1, 30 pp. Vicksburg, Miss. WILLIAMS, JOHN R. 1959. GEOLOGY OF THE WESTERN PART OF THE BIG DELTA (D-6) QUADRANGLE, ALASKA. U.S. Geol. Survey, Misc. Geol. Invest. Map I-297. WILLIAMS, J. R., P:Ew:E, T. L., and PAIGE, R. A. 1959. GEOLOGY OF THE FAIRBANKS (D-1) QUAD- RANGLE, ALASKA. U.S. Geol. Survey, Geol. Quad. Map GQ-124. Map symbol Ad Br Ch EsD EsE EsF FaA FaB FaG FaD FaE FaF FmB FmC FmD FmE FmF GmB GmC GmD GmE GmF GrB GrC GrD GrE GrF GtA GtB GtC Gv Lp Me MnA MnB MnC Sc Sm Ss SuB Sue SuD Ta Map FAIRBANKS AREA, ALASKA GUIDE TO MAPPING UNITS AND MANAGEMENT GROUPS SURVEYED BY DETAILED MAPPING METHOD Mapping unit Alluvial land _______________________________________________________________________________ _ Bradway very fine sandy loam ________________________________________________________________ _ Chena very fine sandy loam __________________________ ~ _______________________________________ _ Ester' silt loam, 12 to 20 percent slopes _________________________________________________________ _ Ester silt loam, 20 to 30 percent slopes _________________________________________________________ _ Ester silt loam, 30 to 45 percent slopes _________________________________________________________ _ Fairbanks silt loam, 0 to 3 percent slopes _____ · __________________________________________________ _ Fairbanks silt loam, 3 to 7 percent slopes _____________________________________________________ .. _ Fairbanks silt loam, 7 to 12 percent slopes ____________________________________________________ .. _ Fairbanks silt loam, 12 to 20 percent slopes ____________________________________________________ _ Fairbanks silt loam, 20 to 30 percent slopes ____________________________________________________ _ Fairbanks silt loam, 30 to 45 percent slopes ____________________________________________________ _ Fairbanks silt loam, moderately deep, 3 to 7 percent slopes _______________________________________ _ Fairbanks silt loam, moderately deep, 7 to 12 percent slopes ______________________________________ _ Fairbanks silt loam, moderately deep, 12 to 20 percent slopes _____________________________________ _ Fairbanks silt loam, moderately deep, 20 to 30 percent slopes _____________________________________ _ Fairbanks silt loam, moderately deep, 30 to 45 percent slopes _____________________________________ _ Gilmore silt loam, 3 to 7 percent slopes ________________________________________________________ _ Gilmore silt loam, 7 to 12 percent slopes _____________________________________ .... ________________ _ Gilmore silt loam, 12 to 20 percent slopes ______________________________________________________ _ Gilmore silt loam, 20 to 30 percent slopes ______________________________________________________ _ Gilmore silt loam, 30 to 45 percent slopes ______________________________________________________ _ Gilmore silt loam, very shallow, 3 to 7 percent slopes ____________________________________________ _ Gilmore silt loam, very shallow, 7 to 12 percent slopes ___________________________________________ _ Gilmore silt loam, very-shallow, 12 to 20 percent slopes __________________________________________ _ Gilmore silt loam, very shallow, 20 to 30 percent slopes _________________________ .. _________________ _ Gilmore silt loam, very shallow, 30 to 45 percent slopes __________________________________________ _ Goldstream silt loam, 0 to 3 percent slopes _____________________________________________________ _ Goldstream silt loam, 3 to 7 percent slopes _____________________________________________________ _ Goldstream silt loam, 7 to 12 percent slopes __________________ ----------------------------------- Gravel pits----------------------------------------------------------------------------------- ~~:tfafii~J;~=============================================================================== Minto silt loam, 0 to 3 percent slopes __________________________________________________________ _ Minto silt loam, 3 to 7 percent slopes __________________________________________________________ _ Minto silt loam, 7 to 12 percent slopes _________________________________________________________ _ Salchaket very fine sandy loam ________________________________________________________________ _ Salchaket very fine sandy loam, moderately deep ___________ ---'-__________________________________ _ Salchaket very fine sandy loam, shallow ________________________________________________________ _ Saulich silt loam, 3 to 7 percent slopes _______________________ -~ ________________________________ _ Saulich silt loam, 7 to 12 percent slopes ________________________________________________________ _ Saulich silt loam, 12 to 20 percent slopes _______________________________________________________ _ Tanana silt loam ____________________________________________________________________________ _ SURVEYED BY RECONNAISSANCE MAPPING METHOD I Page 10 10 10 10 10 11 11 11 11 11 11 11 11 11 11 12 12 12 12 12 12 12 12 13 13 13 13 13 13 13 14 14 14 14 14 14 15 15 15 16 16 16 16 41 Managemmt group Number Page 23 22 14 21 13 21 20 22 20 22 20 22 2 19 4 20 7 20 12 21 16 21 19 22 4 20 7 20 12 21 16 21 19 22 10 20 13 21 17 22 19 22 19 22 13 21 17 22 17 22 19 22 19 22 14 21 15 21 15 21 22 22 21 22 22 22 3 19 5 20 8 20 1 19 6 20 9 20 15 21 15 21 18 22 11 21 symbol Mapping unit Page Ad Alluvialland----------------------------------------------------------------------------------------------10 ERE Ester silt loam, steep_______________________________________________________________________________________ 11 FB D Fairbanks association, moderately sloping to moderately steep___________________________________________________ 12 FEF Fairbanks-Ester association, steep to very steep________________________________________________________________ 12 GEF Gilmore-Ester association, moderately steep to very steep_______________________________________________________ 13 G L Goldstream-Lemeta association______________________________________________________________________________ 13 GS Goldstream-Saulich association______________________________________________________________________________ 13 M S Minto-Saulich association___________________________________________________________________________________ 15 SA Salchaket association_______________________________________________________________________________________ 15 TG Tanana-Q:oldstream association _______________________ ----________________ ,___________________________________ 16 1 Soils surveyed by reconnaissance method were not placed in management groups. 0 1:l U.S. GOVERNMENT PRINTING OFFICE 1974-56.2-419/51 INDEX TO MAP SHEETS FAIRBANKS AREA, ALASKA I R. 2 W. I R. 1 W. I R. 1 E. I R. 2 E.l R. 3 E. R. 4 E. 21 ..... \ T. 3 s.\ ~ ~24 I 10' Scale 1: 253,440 1 0 1 2 3 4 Miles IIIII I I I I I R 5 E R 6 E -===I 16 U. S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE SOIL LEGEND In soil symbols of the detailed soil survey, the first capital letter is the initial one of the soil name. A second capital letter, A, B, C, 0, E, or F, shows the slope. Symbols without a slope letter are those of nearly level soils, such as Tanana silt loam, or of land types, such as Mine tailings, that have a considerable range of slope. DETAILED SURVEY SYMBOL NAME Ad Alluvial land Br Bradway very fine sandy loam Ch Chena very fine sandy loam ~sO Ester silt loam, 12 to 20 percent slopes EsE Ester silt loam, 20 to 30 percent slopes EsF Ester silt loam, 30 to 45 percent slopes FaA FaB FaC FaD FaE FaF FmB FmC FmD FmE FmF GmB GmC GmD GmE GmF GrB GrC GrD GrE GrF GtA GtB GtC Gv Lp Me MnA MnB MnC Sc Sm Ss SuB Sue SuD Fairbanks silt loam, 0 to 3 percent slopes Fairbanks silt loam, 3 to 7 percent slopes Fairbanks silt loam, 7 to 12 percent slopes Fairbanks silt loam, 12 to 20 percent slopes Fairbanks silt loam, 20 to 30 percent slopes Fairbanks silt loam, 30 to 45 percent slopes Fairbanks silt loam, moderately deep, 3 to 7 percent slopes Fairbanks silt loam. moderately deep, 7 to 12 percent slopes Fairbanks silt loam, moderately deep, 12 to 20 percent slopes Fairbanks silt loam, moderately 'deep, 20 to 30 percent slopes Fairbanks silt loam, moderately deep, 30 to 45 percent slopes Gilmore silt loam, 3 to 7 percent slopes Gilmore silt loam, 7 to 12 percent slopes Gilmore silt loam, 12 to 20 percent slopes Gilmore silt loam, 20 to 30 percent slopes Gilmore silt loam, 30 to 45 percent slopes Gilmore silt loam, very shallow, 3 to 7 percent slopes Gilmore silt loam, very shallow, 7 to 12 percent slopes Gilmore silt loam, very shallow, 12 to 20 percent slopes Gilmore silt loam, very shallow, 20 to 30 percent slopes Gilmore silt loam, very shallow, 30 to 45 percent slopes Goldstr@am silt loam, 0 to 3 p@rc@nt slopes Goldstream silt loam, 3 to 7 percent slopes Goldstream silt loam, 7 to 12 percent slopes Gravel pits Lemeta peat Mine tailings Minto silt loam. 0 to 3 percent slopes Minto silt loam, 3 to 7 percent slopes Minto silt loam, 7 to 12 percent slopes Salchaket very fine sandy loam Salchaket very fine sandy loam, moderately deep Salchaket very fine sandy loam, shallow Saulich silt loam, 3.to 7 percent slopes Saulich silt loam, 7 to 12 percent slopes Saulich silt loam, 12 to 20 percent slopes Ta Tanan~ silt loam RECONNAISSANCE SURVEY SYMBOL NAME Ad Alluvial land ER E Ester silt loam, steep FBD FEF GEF GL GS MS SA TG Fairbanks association, moderately sloping to moderately steep Fairbanks-Ester association, steep to very steep Gilmore-Ester association, moderately steep to very steep Goldstream-Lemeta association Goldstream-Saulich association Minto-Saulich association Salchaket association Tanana-Goldstream association Soil map constructed 1962 by Cartographic Division, Soil Conservation Service, USDA, from 1951 aerial photographs. Controlled mosaic on universal transverse Mercator projection based upon Clarke 1866 spheroid, 1927 North American datum. FAIRBANKS AREA, ALASKA WORKS AND STRUCTURES Highways and roads Dual Good motor Poor motor Trail Highway markers National Interstate . u.s. State Railroads Single track Multiple track Abandoned Bridges and crossings Road Trail, foot Railroad Ferries Ford R. R. over R. R. under Tunnel Buildings School Church Station Mines and Quarries Mine dump Pits, gravel or other ..... Power lines Pipe lines Cemeteries Dams Levees Tanks Oil wells Sawmill ================= v 0 0 -+--+--+--+--+- ----->---/<.----- .... =-•--~==== -+---+-))-.--.+-- =====*== == = =*=== .... ijilllliillliiilill • CONVENTIONAL SIGNS BOUNDARIES National or state County Township, U. S. Section line, corner + Reservation Land grant DRAINAGE Streams Perennial Intermittent, unclass. Canals and ditches Lakes and ponds Perennial Intermittent Wells Spring~ Marsh Wet spot Escarpments Bedrock Other Prominent peaks Depressions Crossable with tillage implements. RELIEF Not crossable with tillage implements Contains water most of the time. . ......... .. CANAL DITCH r---..., .._ __ / o + flowing -~-.lllu__illlL_ =---=-~----llL.._-----= vvvv v """ v v vv V V v v v y Yy ,,,,,"''""'""~'"',"''', Large Small 0 ALASKA AGRICULTURAL EXPERIMENT STATION SOIL SURVEY DATA Soil boundary and symbol Gravel Stones Rock outcrops Chen fragments Clay spot Sand spot Gumbo or scabby spot Made land Severely eroded spot Blowout, wind erosion Gullies 0 0 0 0 c 0 0 .·. FAIRBANKS AREA, ALASKA SHEET NUMBER 1 N ! . , ~ '• . FaC "\.• · -~ " 0 c I 0 . .ei ·' . ·r= ill :~ ~ "0 ~ c: :> e .; -~ "' 0 "' ., E c 0 (/) ; :5 ~ ~ c: 0 0 u c: ;: 0 0 "' ..c: . (/) -" ~ ~ Q) " E i 0 u c: 0 ~ :;::; u Q) 0 (/) "0 c: . "' . . a: . -~ "' ..c: "' (/) 2: c: iii ;: E c .8 .. I "' ~ Q co E c: "' 8 "' 0:: = ~ . ~ 0 ;;, . <( ~ . .. .!! : .< .. E:5 .!! ~ -" ... FAIRBANKS AREA, ALASKA SHEET NUMBER 2 0 N 1 (Joins sheet 10) 0 1 Mile Scale 0 1:31680 5 000 Feel 0 3: " (/) (') "' iD ,_. w ...... 0'\ CXI 0 ·-~~----·-~---J This map IS one of a set comp1led fn 1962 as p;ut ot a so1l survey D)r the So1! Con:;.ervabon Ser-.nce, Untt.:tr:l. 5tate~ lJ~ptHtmllnt ·~f A"£r\c.u\t\lr-a. and the Alaska Agricultural Experiment Station Range, township, and sectio11 corners shown on this map are indefinite. ·-~--·--·-·-... ·-~-~-----... --·~---~-~-· ~ .. ·-· ---~ • '-'--~ ·~·----·-"•~-••~, -, ··--~-~-w ····· ···--· ·-·~ ···-----~-.. ---------~-.. -· ···~ ----., ., )> :::0 OJ )> z ::0:: (f) )> :::0 rn x~--·· :•·.s~ •. :J !> · ~:; .t~'·' ., ", . ·r .... , ~~~~:'~ ,~;· . ' )> r ·~;:: ?~-.. ":~~: -\ ', ~~~ ~~ )> (f) ., ~~~' ,, ::u ~ . .,·,1, ,1, )> ;:,,:_ ..:: .. ·-·· f-' ... ·--· ~-··---~-~----······--(f) I rn rn -! z c s OJ rn :::0 w z 8 0 7!: FAIRBANKS AREA, ALASKA SHEET NUMBER 4 PROJECT ·' -- N ! 0 Scale 1:31680 L_____._l, __ _L ___ ..J._ __ c__ _ __J FAIRBANKS AREA, ALASKA SHEET NUMBER 5 r R. 3 E. 0 N 1 ~ ] -~ "" 0 c t 0 . ~ ~ G c iii <;::: "0 Q) ~ "0 '<0 c ::;) ~ ~ u "' -~ Cl. "' Vl E c Vl 0 m :5 > ~ c c 0 0 c u ;: . ., 0 Vl .r:. ~ Vl .c ~ I; Q) "' E ~ 0 > u 0 c . 0 ·~ :,::; u Q) Vl 0 "0 c . "' a . ci G c .r:. N 0 Vl "' m c ~ iii ;: c c .8 ~ -1 "' bO -~ c "' w 0:: . ~ . 0 . ] 0 -~ ~ <( c 0 "" . . 0. :;( i1 . .c "0 ~ ~ G FAIRBANKS AREA, ALASKA SHEET NUMBER 6 R. 4 E. N 1 (Joins sheet 14) 0 1 Mile 0 5 000 Feet Seale 1 : 31 680 L__-J. __ _J_ __ .L__ _ ___.L __ _J r FAIRBANKS AREA, ALASKA R. 5 E. SHEET NUMBER 7 0 N I ~ ~ fi, < 0 c t 0 . 2 .!!1 c "' ~ e "0 . ., c ::> . ~ u "' -~ n "' (J) E c 0 -~ i :5 c 0 u c 3: ·a 0 '" ..c . "' .c Vl >-}; (lJ c ~ ..... 0 ~ 0 c 0 -~ ~ 0 (lJ 0 Vl "0 c . "' 0. c:i "' c ..c 0 Vl "' ~ c ~ iii 3: c 0 c ~ ] ·I "' ~ tlD c "' 3 "' 0:: . ~ 3 0 -~ t;, . < c 0 . ~ . . . 0. < E . .c z 11 .., ...... ,._ :; ....: oL_ __ ........ ___ ....~... ___ .L.. __ __.1 Mile Scale 1 : 31 680 FAIRBANKS AREA, ALASKA SHEET NUMBER 8 ® I R. 6 E. N I ;\ \. .r \. ~<-1 ":];.%~.~~~~,-~ ,l) . ·. r<C" . .,_.;:-;·.-..... ··· ;_::~~:;:{_ ·~ .GEF FAIRBANKS AREA, ALASKA SHEET NUMBER 9 0 N 1 rl ~ r-= l "" 0 c I 0 . _ _g . iii c: :;::: " (j) . v ·o: c: ::J 2: .~ "' ~ 0. "' "' E c 0 VJ ~ :S i c: 0 u c: 0 ~ 0 "' ..c: . if) ~ ~ ~ Q) ~ c: ~ . 0 > ·U , c: ~ 0 u Q) 0 if) v c: " "' ci. c ..c: "' 0 VJ "' ~ c ~ iii ~ c c .8 " ~ a) . l 1 bD c: ,;j "' [Y . ~ . ] " <;; . "' c 0 ~ ·- " <( !1 . .c . ~ :c >- Sc L 0 0 FAIRBANKS AREA, ALASKA SHEET NUMBER 10 ® N 1 1 Mile Scale 1:31680 FAIRBANKS AREA, SHEET NUMBER 11 @ N ! l '£ « 0 c f 0 . ~ . . c iii ~ "0 21 -a c c ::0 ~ ·~ "' 0. "' <f) E c <J) 0 i _c ~ c 0 () c ;: 0 0 <f) _c . U) .c ~ 11 Q) c ~ I.. 0 u c 0 ·~ ~ .... u ~-Q) U) '0 u c "' 0. . ci ro c N 0 _c "' ro <J) ~ c U) ;: c c . .8 . E a) ·a. -~ tlO c ~ "' w 0:: . " ro ] o -~ . « c ro 0 ~ . . ro 0. :0: E . .c ·------ 0 Scale 1:31680 FAIRBANKS AREA, ALASKA SHEET NUMBER 12 @ N I FAIRBANKS AREA, SHEET NUMBER 13 DETAIL.ED SOIL. SURVEY -~~-·~:~·-:. ® N z ...... ,_: 1 uj ~ ...... ] ,_: ·-= It b c f 0 ~ 1i . ii) ·c: :;::: "0 Q) . "0 ·c c :J ci" ~ ro -~ n. ro <n E c 0 .~ l -5 c 0 0 u c :s 3: 0 <n £ . <n -" ~ ~ Q) .Q E f 0 u ~ c ~ 0 :;:; u Q) b "' "0 c . ro a ~ cl . c N £ <D ~ "' ~ c ii) 3: c 0 c .,.., "0 E w . ·a. -~ llO c ~ "' UJ 0:: ~ ~ . ~ b -~ . ..: c 0 . ~ ~ ~ . a < 11 0 :r 1- -- 0 1 Mile Scale 1; 31680 L---~----~----~--~ 0 5 000 Feet FAIRBANKS AREA, ALASKA SHEET NUMBER 14 ..... B ..... 1 .. ~: ............ ....,.,._ ... ,, ... ,, .. ,....,"'f.'ir ... , .... : ...................... _,.,~-~--.. .,.-.,. 0 l Mile 0 Scale 1:31680 5000 Feet ........ .. . !. .J ~!.~ _ .... .. ~ ..... ... . --~"' I ... -.~,.:"~ .. · .. ~·- .. TG -. ' .. --.,_ :Z -.~"" .,_ ..-1 --":~ .....= ,, ·-.. ui ..-1 ..J FAIRBANKS AREA, SHEET NUMBER 15 N '·~ 1 ~ . , ! "" 0 c t 0 . 2 iii c y:: -o (1) . -o c c :::J .~ ~ ro > o_ . ro (f) E c 1 (f) :5 c 0 0 u c ·a 3 0 (f) _c: . (f) ~ ]; Q) c ~ ~ 0 u c g 0 ·.;::; u (1) 0 (f) -o c a ro ~ o_ c N 0 _c: <!) :g (f) ~ c iii 3 c c .8 -o I a) . ·a_ tlD ~ c ro w a: . ~ ~ ] 0 " " <( c ~ 0 ~ . ·-~ a :;;: E' . ~ . ] L ~ f-- 0 !Mile Scale 1:31680 L_ ____ L_ ____ ~----~----~ 0 5000 Feet N 1 L FAIRBANKS AREA, ALASKA SHEET NUMBER 16 . ; .. J;J -?74 -.· ~ . ,~.~. ·l".ti":,"J'}.-: . . ... J ,.. r 0 Y2 I Mile 0 5000 Feet L_ __ .J._ __ _L __ ---~. __ .__~ Scale 1 : 31680 L----L-__JL-_....L _ ___J __ _J _j 0 ~ [~ Ul (') I» ii' ..... w ..... 0\ Ol 0 3: ;.-0 "' 0 0 0 ., .. ~ ) r L This map is one of a set compiled in 1962 as part of a soil survey by the Soil Conservation Service, United States Dep;~~rtment ot Asriculture, and the Alaska Agricultural Experiment Statior. Range, township, and section corners shown on this map are indefinite. ~ -·J ·~fA <li ~ ~ ,...,. 1 \"'· 1 ~ ' ~ ~ .. ~~·· ~\~~i .. :' ~./ !t;·' ';i.!t ·k: 7 ~£ \ }; )> ::0 fT1 '}> )> ~ en :A ;;o)> z © en :c fT1 ~ z c s OJ fT1 ::0 ....... ""-~ FAIRBANKS AREA, ALASKA SHEET NUMBER 18 R. 1 W . . T . ···- N MlllTARY ) 25 RESERVA'TlON • ' ' - L _j 0 1 Mile Scale 1:31680 0 5 000 Feet - ~ 0 ] ·~ <( 0 c t 0 ~ 2 m ·c: iii ~ " ~ '0 ·;:: c :> ~ e u ro 0. ~ ro Ill E c 0 .~ . :5 > . c c 0 0 (.) c ·a ;: 0 <II .c ~ <II .<= ~ .. Q) .0 E ~ ~ 0 > u 0 c 0 -~ ~ "' 0 <f) '0 c . ro 0. ci: N c .c 0 <f) "' ~ c ~ iii ;: c c .8 u I ai . ~ bO c ro w 0:: ~ ~ 0 ~ ! 0 ~ c <( 0 . 0 0 . 0. < 1: ~ ,;: 0 u :<: c 1--. AREA, SHEET NUMBER 19 ' 26 r A. f. ~ I ---- IL 0 1/2 1 Mile 0 5 000 Feel ~__ __ _L __ __iL-__ ...~._ __ ~ Scale 1: 3 1 680 L,_ _ _l,.. __ ...._ _ __.~, __ __i__ _ __. ·~ Br · '\;' .;. ·~ . " \ . .... -~"!5'~ """" . ,,....':\,~· ·M''·25 N I FAIRBANKS AREA, ALASKA SHEET NUMBER 20 (Joins sheet -· L 0 1 Mile Scale 1:31680 0 5000 Feet (Joins sheet 22) FAIRBANKS AREA, ALASKA SHEET NUMBER 21 N l ~ ] j 0 " ~ ~ 0 ~ 2 ;;; c ] ~ "0 . ., c :> ~ ~ u "' ·~ a. </) "' E 0 0 -~ ~ :5 > ~ c . c 0 0 u c ·;; ;: 0 </) ..c ~ (/) .c ~ }; <ll c ~ \... 0 u c 0 ·~ :;:; u <ll 0 (/) "0 c . " "' ~ 0: N c :<: 0 </) "' ·; c ~ ;;; ;: 0 0 .8 '0 ~ ai . ·~ -~ 00 c "' g '" a:: . ~ ~ . 1i 0 ·~ . c <( 0 ~ ·- " < E ~ .c . ~ :c .... --- _j 1:31680 r N I b_ FAIRBANKS AREA, ALASKA -SHEET NUMBER 22 1 Mile 0 '---------lL------1-----L--_l Scale 1 :31680 0 5000 Feet ~-~-J_--_L_~-~ (24) FAIRBANKS AREA, ALASKA -SHEET NUMBER 23 N I . ~ a 'fi < 0 c I a ~ 2 . . c iii ~ "C . "tJ "2 c :::) ~ ~-co ., a. ~ co "' E c .~ 0 . :5 i c 0 0 c 3: ·a 0 "' ..c . "' ~ "' ~ Q; D ~ ~ ~ 0 0 c 0 ·~ :.:::; 0 Q) 0 "' "tJ c . 0. co ci ~ c" . ..c N ~ "' "' c ~ u; 3: c c .8 . ]: . § "' l ~ tlO e-c co "' 00: :: ~ . a 0 -~ . < c . 0 ~ ~ ~ . 0. < l1 ~ ~ ~ :c .... ... ~ ,~ . \ ... I ., .; . • . ~. \ ) . \ t',.,"' .J • ~ ... ~,- 5000 Feet 11'2 1 Mile 0 L-----L __ __, ___ .._ __ _~ Scale 1: 31680 L----'----'-----'----L----' FAIRBANKS AREA, ALASKA -SHEET NUMBER 24 N 1 L 0 1 Mile 0 5 000 Feet Seale 1 : 31 680 '---...L..--...L...-_ _,__......._ _ __, U. S. DEPARTMENT OF AGRICULTURE SOIL CONSERVATION SERVICE WORKS AND STRUCTURES Highways and roads Dual ................................................. . Good motor Poor motor Trail Highway markers National Interstate ...................... . u.s .················································· State ...................... ., ..................... .. Railroads Single track Multiple track Abandoned Bridges and crossings Road Trail, foot Railroad Ferries Ford Grade R. R. over R. R. under Tunnel Buildings School Church Station Mines and Quarries .......................... . Mine dump ..................................... . Pits, gravel or other ........................ .. Power lines --==~=========== v 0 0 -+--+--+- -+--+- ----->c-----1<----- ..... ===1--&--j=== =~=====I== I I 1 ff' I I -))---+---+- ===*'=====~ ... Pipe lines ......................................... 1-i 1-i H 1-< 1-i t- Cemeteries r--, 't' I ' ~ Dams Levees I I I I I I II I I I II I I II I L Tanks • Oil wells Sawmill CONVENTIONAL SIGNS BOUNDARIES National or state County Township, U. S. Section line, corner .................................. + Reservation Land grant DRAINAGE Streams Perennial Intermittent, unci ass . Canals and ditches • Lakes and ponds Perennial lntermitten't ................................ .. Wells ................................................ .. Springs .................................................. . Marsh Wet spot .......................................... . RELIEF Escarpments Bedrock Other ................................................ . Prominent peaks Depressions Crossable with tillage implements ............................... .. Not crossable with tillage implements ............................... . Contains water most of the time ..................................... .. CANAl. DITCH /"----, ._ __ / o + flowing: --"lf,_-..ulu...-..;U.._ =-------=-~-~ --~ ,,.,,•"'""'"""''"'rtnU'''" Large Small ;~~:;~ 0 FAIRBANKS AREA, ALASKA SOIL SURVEY DATA Soil boundary and symbol Gravel Stones Rock outcrops Chen fragments Clay spot Sand spot Gumbo or scabby spo t Made land Severely eroded spot ......................... . Blowout, wind erosion Gullies ................................................... . 0 0 0 0 0 v v v .•. ALASKA AGRICULTURAL EXPERIMENT STATION SOIL LEGEND In soil symbols of the detailed soil survey, the first capital letter is the initial one of the soil name. A second capital letter, A, B, C, D, E, or F, shows the slope. Symbols without a slope letter are those of nearly level soils, such as Tanana silt loam, or of land types, such as Mine tailings, that have a considerable range of slope. SYMBOL Ad Br Ch t::sD EsE EsF FaA FaB FaG FaD FaE FaF FmB FmC FmD FmE FmF GmB GmC GmD GmE GmF GrB GrC GrD GrE GrF GtA GtB GtC Gv Lp Me MnA MnB MnC Sc Sm Ss SuB sue SuD Ta SYMBOL DETAILED SURVEY NAME Alluvial land Bradway very fine sandy loam Chena very fine sandy loam Ester silt loam, 12 to 20 percent slopes Ester silt loam, 20 to 30 percent slopes Ester silt loam, 30 to 45 percent slopes Fairbanks silt loam, 0 to 3 percent slopes Fairbanks silt loam, 3 to 7 percent slopes Fairbanks silt loam, 7 to 12 percent slopes F~i r banks silt loam, 12 to 20 percent slopes Fairbanks silt loam, 20 to 30 percent slopes Fairbanks silt loam, 30 to 45 percent slopes Fairbanks silt loam, moderately deep, 3 to 7 percent slopes Pairbanks silt loam, moderately deep, 7 to 12 percent slopes Fairbanks silt loam, moderately deep, 12 to 20 percent slopes Fairbanks silt loam, moderately 'd~ep, 20 to 30 percent slopes Fa irbanks silt loam, (lloderately·deep, 30 to· 45 percent slopes Gilmore silt loam, 3 to ·7 percent slopes Gilmore silt loam, 7 to 12 percent slopes Gilmore silt loam, 12 to 20 percent slopes Gilmore silt 'loam, 20 to 30 percent slopes Gilmore silt loam, 30 to 45 percent slopes Gilmore silt loam, very shallow, 3 to 7 percent slopes Gilmore silt loam, very shallow, 7 to 12 percent slopes Gilmore silt loam, very shallow, 12 to 20 percent slopes Gilmore silt loam, very shallow, 20 to 30 percent slopes Gilmore silt loam, very shallow, 30 to 45 percent slopes Goldstream silt loam, 0 to 3 percent slopes Goldstream silt loam, 3 to 7 percent slopes Goldstream silt loam, 7 to 12 percent slopes Gravel pits Lemeta peat Mine tailings Minto silt loam. 0 to 3 percent slopes Minto silt loam, 3 to 7 percent slopes Minto silt loam, 7 to 12 percent slopes Salchaket very fine sandy loam Salcoaket very fine sandy loam, moderately deep Salchaket very fine sandy loam, sh ~ll ow Saulich silt loam, 3 to 7 percent slopes Saulich silt loam, 7 to 12 percent slopes Saulich silt loam, 12 to 20 percent slopes Tanana silt loam RECONNAISSANCE SURVEY NAME Ad Alluvial land ERE FBD FEF GEF GL GS MS SA TG Ester silt loam, steep Fairbanks association, moderately sloping to moderately steep Fairba n ks-Ester association, steep to very steep Gilmore-Ester association, moderately steep to very steep Gold strea m-Lemeta association Gol dstre am-Saulich association Minto-Saulich association Salchaket association Tanan a-Goldstream association Soil map constructed 1962 by Cartographic Division, Soil Conservation Service, USDA, from 1951 aerial photographs. Controlled mosaic on universal transverse Mercator projection based upon Clarke 1866 spheroid, 1927 North American datum. N - INDEX TO MAP SHEETS FAIRBANKS AREA, ALASKA R. 5 E. R. 4 E. I R. 1 E. I R. 2 E.! R. 3 E. R ONNAISSANCE I R. 6 E. 21 l \_ r. 3 s\ ~ '\:24 I 10' Scale 1: 253,440 1 o 1 2 'f A Miles 111111 I I-~ 16 0 0 0 .-!)". 0 •• ,,, Detailed Soil Survey The boundaries and location of the Fairbanks Area in Alaska.