LOCATION FALK IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, nonacid, mesic Aquic Xerorthents
TYPICAL PEDON: Falk fine sandy loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak very fine granular structure; soft, very friable, slightly sticky; many roots; many very fine and fine pores; slightly acid (pH 6.4); abrupt smooth boundary. (5 to 9 inches thick)
C1--8 to 14 inches; light brownish gray (10YR 6/2) fine sandy loam, dark brown (10YR 4/3) moist, weak medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky; many fine roots; many very fine and fine tubular pores; slightly acid (pH 6.4); clear smooth boundary. (4 to 18 inches thick)
C2--14 to 25 inches; pale brown (10YR 6/3) fine sandy loam, dark brown (10YR 4/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, slightly sticky; many fine roots; many very fine and fine tubular pores; neutral (pH 6.8); gradual smooth boundary. (10 to 20 inches thick)
C3--25 to 35 inches; light yellowish brown (2.5Y 6/3) fine sandy loam, olive brown (2.5Y 4/3) moist; many medium distinct gray (5Y 5/1) and dark brown (10YR 3/3) mottles moist; massive; slightly hard, very friable, slightly sticky; few roots; few very fine pores; neutral (pH 6.9); abrupt wavy boundary. (8 to 24 inches thick)
2C4--35 to 60 inches; mottled sand and gravel; single grained; loose.
TYPE LOCATION: Gem County, Idaho; about 2 miles northeast of Emmett; 380 feet north and 120 feet west of the center of section 4, T. 6 N., R. 1 W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 49 to 54 degrees F.
Average summer soil temperature - 66 to 71 degrees F.
Depth to loose sand or pebbles or both - 20 to 40 inches
Organic matter - low or moderately low, decreases regularly with depth Depth to mottles - 20 to 40 inches
Reaction - neutral or slightly acid
Ap horizon (or upper 7 inches when mixed)
Hue - 10YR or 2.5Y
Value - 5 or 6 dry, 3 or 4 moist (Not darker broken and rubbed than 5.5 dry, 3.5 moist.)
Chroma - 2 or 3 dry and moist
C horizons
Hue - 10YR or 2.5Y
Value - 6 through 8 dry
Chroma - 2 or 3, dry or moist
Texture below 10 inches and above the sand and pebbles - averages less than 18 percent clay, less than 50 percent coarser than very fine sand, less than 20 percent pebbles or other coarse fragments, dominantly a fine sandy loam.
COMPETING SERIES: These are the similar Chance, Emerson, and Moulton series. Chance soils have dominant chroma of 1 and are mottled throughout the sola, and they are saturated with water most of the year unless artificially drained. Emerson soils are usually dry and lack mottles. Moulton soils have mottles beginning at depths of 8 to 20 inches.
GEOGRAPHIC SETTING: The soils is on high bottom lands or very low terraces. Slopes are 0 to 3 percent. Elevations range from 2,000 to 3,500 feet. The soils formed in recent alluvium derived dominantly from acid igneous rocks. The average frost-free period is 140 to 160 days, and average annual precipitation is 8 to 12 inches, including 1.5 to 3 feet of snow. Average annual air temperature is 47 to 52 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Chance, Emerson and Moulton soils and the Notus soils. Notus soils are less than 20 inches deep to sand and gravel.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; moderately rapid permeability. The water table fluctuates seasonally between 36 to 60 inches. The soil floods under abnormal conditions.
USE AND VEGETATION: Mainly irrigated and cultivated. Alfalfa and clover hay, corn, small grains, sugar beets, and improved pasture are grown.
DISTRIBUTION AND EXTENT: Southwestern Idaho and possibly Oregon and Nevada. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gem County, Idaho, 1949.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 8 inches (Ap horizon)
Particle size control section - the zone from 10 inches to 35 inches over sand, pebbles or both at 35 inches
Mottles - at 25 inches
Moisture regime - Xeric
Temperature regime - Mesic