LOCATION FIRTH ID+WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Aquic Haplocryolls
TYPICAL PEDON: Firth sandy loam - irrigated cropland (Colors are for dry soil unless otherwise noted).
Ap--0 to 6 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; soft, very friable, nonsticky, nonplastic; many very fine and fine roots; many very fine interstitial pores; slightly calcareous; mildly alkaline (pH 7.6); clear smooth boundary. (0 to 8 inches thick)
A1--6 to 12 inches; grayish brown (10YR 5/2) sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; slightly hard, friable, nonsticky, nonplastic; common very fine and fine roots; many very fine and fine pores; slightly calcareous; mildly alkaline (pH 7.6); gradual smooth boundary. (4 to 12 inches thick)
C1--12 to 24 inches; light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium and fine granular structure; soft, very friable, nonsticky, nonplastic; common very fine and fine roots; many very fine and fine pores; moderately calcareous; mildly alkaline (pH 7.8); gradual wavy boundary. (8 to 14 inches thick)
C2--24 to 40 inches; light brownish gray (10YR 6/2) sandy loam, grayish brown (10YR 5/2) moist; common medium distinct mottles, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky, nonplastic; common very fine and fine roots; many very fine and fine pores; strongly calcareous; mildly alkaline (pH 7.8); gradual wavy boundary. (12 to 24 inches thick)
IIC3--40 to 60 inches; light gray (10YR 7/1) silt loam, grayish brown (10YR 5/2) moist; many medium prominent mottles, dark yellowish brown (10YR 3/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; common very fine and fine roots; many very fine and fine tubular pores; strongly calcareous; moderately alkaline (pH 8.2). (0 to several feet thick)
TYPE LOCATION: Bingham County, Idaho; about 3 miles south and 1.5 miles west of Wapello; 150 feet west and 1,325 feet south of the center of sec. 31, T.2S., R.36E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 41 to 47 degrees F. and the mean summer temperature at depth of 20 inches ranges from 59 to 66 degrees F. They are not saturated with water throughout for some period but are saturated within 40 inches of the surface for some period unless artificially drained. Mottles with chroma of 2 or less are within 40 inches of the surface but are commonly below 20 inches. The 10- to 40-inch control section is dominantly moderately coarse textured and has a weighted average of less than 18 percent clay, more than 15 percent particles coarser than very fine sand, and less than 15 percent rock fragments. The organic matter content decreases regularly with depth and reaches a level of 0.5 percent or less within 50 inches of the surface. The mollic epipedon (and solum) is 7 to 16 inches thick. The A horizon has hue of 10YR or 2.5Y, value of 4 to 5.5 dry and 2 to 3.5 moist, and chroma of 1.5 or 2. It has weak or moderate granular structure or has weak platy structure in the upper few inches. This horizon ranges from slightly to moderately calcareous and from mildly to strongly alkaline. The C horizon has hue of 10YR or 2.5Y, value of 5.5 through 7 dry and 3.5 through 5 moist, and chroma of 1 or 2. It is dominantly moderately coarse textured, but medium textured layers may be below a depth of 30 inches. This horizon is moderately or strongly calcareous but does not qualify as a calcic horizon because of lack of decrease in carbonates. Some pedons are saline or (and) alkali-affected.
COMPETING SERIES: These are the Balm, Blackfoot, Kodak, Martini, Parehat, Sunset, Syracuse, Vineyard, and Weeding series. Balm soils have a layer of loose sand and gravel above 40 inches. Balm, Kodak, Martini, Parehat, Sunset, Vineyard, and Syracuse soils have mean annual soil temperatures warmer than 47 degrees F. Blackfoot, Parehat, and Sunset soils have medium-textured control sections. Blackfoot, Kodak, Martini, and Parehat soils have an organic matter content that does not decrease regularly with depth to a level of 0.5 percent or less within 50 inches of the surface. Syracuse and Vineyard soils have calcic horizons. Weeding soils have a loamy sand control section.
GEOGRAPHIC SETTING: The soils are in level to very gently sloping terraces at elevations of 4,300 to 6,000 feet. Slopes are dominantly less than 2 percent and range from 0 to 4 percent. The soils formed mostly in moderately coarse textured alluvium, in most places over lake-laid sediments. The alluvium is dominantly from quartzite and sedimentary rock sources but contains some rhyolite, basaltic, and granitic materials. In places the upper part may be eolian sediments. The climate is semiarid. Mean annual precipitation is 8 to 13 inches, including 1.5 to 5 feet of snowfall. Average freeze-free period is 94 to 126 days.
PRINCIPAL ASSOCIATED SOILS: These are the Fulmer, Wapello, and Wolverine soils and the competing Weeding soils. Fulmer soils are medium textured and poorly drained. Wapello and Wolverine soils lack mottles. Also, Wolverine soils are dominantly sand between depths of 10 and 40 inches.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow or medium runoff; moderately rapid permeability in the A and upper C and moderate in the IIC horizon. The fluctuating water table is between depths of 20 and 40 inches for short periods in spring or fall.
USE AND VEGETATION: Mostly cultivated under irrigation for hay, pasture, potatoes, and small grains. The natural vegetation is mainly big sagebrush, rabbitbrush, streambank wheatgrass, Indian ricegrass, basin wildrye, and needle-and-thread grass.
DISTRIBUTION AND EXTENT: The series is inextensive in the terraces of the Upper Snake River valley and the tributary valleys in Eastern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Bingham County, Idaho, 1972.
REMARKS: The soils were classified formerly as Regosols.
OSED scanned by SSQA. Last revised by state on 4/72.