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Map Unit No. AW•,Fine, Mixed, Pachic Crycfluvents 0 to 3 percent slopes. <br />This gently sloping, well drained soil is on bottoms", narrow valleys and <br />drainageweyg• Slopes are smooth but may have a gullied center. The native <br />vegetation is mainly grasses, sagebrush with some willows, alders and cotton- <br />wood along stream banks. Elevation is 6550 to 7050 feet. The average annual <br />precipitation is about 16.5 to 18.0 inches, the average annual air temperature <br />is 44 to 42 degrees F., and the average frost-free period is 85 to 94 days. <br />Soil temperatures are in the cryic soil zone. Individual areas of this unit are <br />long, winding and narrow in shape and range from 1 to 10 acres in size. <br />Typically the dark gray to nearly black (lOYR 4/2-2/2) loam to silty clay <br />loam surface layer is about 10 inches thick but ranges from 7 to 20 inches <br />thick. It varies widely in texture, stratification and depth of organic matter <br />coloration.„'andy clay loams, loams and clay loams predominate. The C horizon <br />is indistinct and, locally,grades from the B horizon into mixed gravels, sands <br />and stones. It is underlain by ground water at depths of 50" to 60" or more in <br />places but many small stream beds are dry most of the growing season. Electri- <br />cal conductivity may range as high as 3.5 at depths below 45 inches. Sodium <br />Absorption Ratios are low, The soil reaction is near neutral and <br />no excess salts occur. Included with this soil in mapping are small areas of <br />sand and gravel bars, gullies and stream banks of no usable quality. <br />Water and air move through this soil at a moderate rate and surface runoff is <br />low except when streams are flooded. Root developement may be resticted below a depth <br />of about 50-60 inches by local water tables but is generally good throughout <br />the soil profile. <br />This unit is a good source for topsoil. Quality of topsoil is limited by the <br />presence of ground water or beds of gravel in places. Quantity of suitable <br />topsoil does not appear to be limited is depth except where local water tables <br />or gravel beds exist. Testing along a valley floor will reveal potential <br />cutting depths. Topsoil salvage operations are feasible and are limited only <br />by the narrow confined tracts between slopes of 20-50 percent (valleywalls).which <br />makE access difficult. No evidences of minor element toxicity were found. <br />s <br />-15- <br />