LOCATION HARPT IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Torrifluventic Haploxerolls
TYPICAL PEDON: Harpt loam - cultivated. (Colors are for dry soil unless otherwise noted).
Ap--0 to 10 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine pores; slightly acid (pH 6.2); abrupt smooth boundary. (7 to 12 inches thick)
A--10to 31 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; many very fine and fine pores; slightly acid (pH 6.3); gradual smooth boundary. (13 to 28 inches thick)
C--31 to 46 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; many very fine and fine pores; neutral (pH 6.8); abrupt smooth boundary. (10 to 20 inches thick)
2C2--46 to 80 inches; light brownish gray (10YR 6/2) coarse sandy loam, light olive brown (2.5Y 5/3) moist; massive; slightly hard, very friable; few fine roots; neutral (pH 6.9).
TYPE LOCATION: Gem County, Idaho; about 3 miles south of Emmett; 120 feet south and 550 feet west of the center of southeast 1/4, section 19, T. 6 N., R. 1 W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 47 to 54 degrees F.
Average summer soil temperature - 66 to 74 degrees F.
Mollic epipedon - 7 to 19 inches thick
Organic carbon - decreases to less than 0.6 percent at depths below 20 inches.
10 to 40 inches
clay percent - 18 to 27
sand percent - more than 15 percent coarser than very fine sand, less than 15 percent pebbles or other coarse fragments.
Texture - dominantly loam
A horizons
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry and moist
Organic matter - does not decrease regularly with depth
Reaction - neutral or slightly acid
One or more buried A horizons are common
C horizons
Hue - 10YR or 2.5Y
Value - 5 through 7 dry, 3 through 5 moist
Chroma - 2 or 3 dry and moist
Textures below 25 to 30 inch depth - strata of SL, SCL, CL, SIL Reaction lower part - slightly acid to mildly alkaline
Some pedons have a Bw horizons
COMPETING SERIES: This is the Etta and Juab series. Etta soils have a clay loam control section with 27 to 35 percent clay. Juab soils are calcareous.
GEOGRAPHIC SETTING: The Harpt soils are on alluvial fans at elevations of 2,000 to 4,500 feet. The soil formed in recent alluvium derived mainly from acid igneous rocks. Slopes are 0 to 30 percent. The climate is semiarid and summers are dry. The frost-free period is 120 to 160 days, and the average annual precipitation is 9 to 13 inches, including 1.5 to 4 feet of snowfall. Average annual air temperature is 45 to 52 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cashmere soils. Cashmere soils are coarse loamy and are on similar landscape routines.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderate permeability.
USE AND VEGETATION: Mostly irrigated cropland; a small part is used for grazing. Orchards are important; the main crops are corn, potatoes, small grains, sugar beets, and alfalfa hay. Vegetation is chiefly big sagebrush, bluebunch wheatgrass, Thurbers needlegrass, Sandberg bluegrass, cheatgrass, and giant wildrye.
DISTRIBUTION AND EXTENT: Southwestern Idaho and possibly Oregon, and Nevada. Moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gem County, Idaho, 1962.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 10 inches (Ap horizons)
Contrasting textures - at 46 inches
Moisture regime - Torric borders on xeric
Temperature regime - mesic
Organic matter - does not decrease regularly with depth