LOCATION GREENTIMBER IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Palexerolls
TYPICAL PEDON: Greentimber silt loam, on a two percent convex north slope at 5,560 feet elevation under barley stubble. When described on October 11, 1983, the profile was moist throughout. (Colors are for dry soils unless otherwise noted.)
Ap--0 to 6 inches; dark brown (10YR 4/3) silt loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; few very fine tubular pores; about one percent pebbles; moderately acid (pH 5.8); abrupt smooth boundary. (5 to 10 inches thick)
AB--6 to 20 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; strong medium subangular blocky structure; hard, firm, slightly sticky and plastic; common very fine and fine roots; common very fine and fine tubular pores; about one percent pebbles; moderately acid (pH 6.0); abrupt wavy boundary. (10 to 15 inches thick)
Bt--20 to 31 inches; yellowish brown (10YR 5/4) silty clay loam, dark yellowish brown (10YR 4/4) moist; moderate coarse prismatic structure parting to strong fine prismatic; very hard, very firm, sticky and plastic; common very fine and few fine roots; few very fine and common fine tubular pores; common uncoated silt grains on faces of peds; many moderately thick clay films on faces of peds and in pores; about five percent pebbles; slightly acid (pH 6.4); clear wavy boundary. (10 to 15 inches thick)
Btb1--31 to 57 inches; brown (7.5YR 5/4) clay loam, dark brown (7.5YR 4/4) moist; strong coarse prismatic structure parting to strong medium angular blocky; very hard, very firm, sticky and plastic; few very fine and fine roots; few fine tubular pores; many thin clay films on faces of peds; about five percent pebbles and one percent cobbles; slightly acid (pH 6.4); clear wavy boundary. (20 to 30 inches thick)
Btb2--57 to 60 inches; yellowish brown (10YR 5/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate coarse prismatic structure parting to strong medium subangular blocky; very hard, firm, sticky and plastic; few fine tubular pores; few thin clay films on faces of peds; about 20 percent pebbles and 10 percent cobbles; slightly acid (pH 6.4).
TYPE LOCATION: Fremont County, Idaho; approximately six miles east and one mile north of Marysville, about 1000 feet north and 250 feet west of the southeast corner of Section 18, T.9N., R. 44E.
RANGE IN CHARACTERISTICS:
Soil temperature - 40 to 44 degrees F.
Control section averages - Percent clay: 35 to 45
Percent pebbles - 1 to 10 percent
Percent cobbles and stones - 0 to 5 percent
Solum thickness - greater than 60 inches
Ap and AB horizons
Value- 4 or 5 dry
Chroma- 2 or 3 dry and moist
Bt horizon
Value- 4 or 5 dry, 3 or 4 moist
Chroma- 3 or 4 dry and moist
Texture - SICL, CL
Btb1 horizon
Hue- 10YR or 7.5YR
Value- 4 or 5 dry, 3 or 4 moist
Chroma- 3 or 4 dry or moist
Texture - CL, C, SIC
Btb2 horizon
Hue- 10YR or 7.5YR
Value- 4 or 5 dry, 3 or 4 moist
Chroma- 3 or 4 dry and moist
Texture - GR-CL, GR-C, GRV-CL
Percent pebbles - 15 to 25 percent
Percent cobbles and stones - 3 to 20 percent
COMPETING SERIES: These are the Goring, Prag, and Skullgulch. Goring soils lack buried argillic horizons and abrupt texture change at the top of the argillic. Prag soils are moderately deep to partially consolidated sediments. Skullgulch soils have more than 45 percent clay in the Bt horizon and secondary carbonates in the lower part of the argillic at a depth of 40 to 60 inches.
GEOGRAPHIC SETTING: Greentimber soils are on plains and moraines at elevations of 5300 to 5700 feet. Slopes range from 1 to 4 percent. They formed in loess mantled glacial drift derived from mixed igneous rocks, mainly rhyolite and basalt. Greentimber soils have an average annual air temperature of 39 to 43 degrees F and an average annual precipitation of 16 to 22 inches. The frost-free season is 75 to 85 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kucera, Lostine, and Marystown soils. Kucera and Lostine soils are in very deep loess deposits on adjacent uplands. Marystown soils are intermixed with the Greentimber sols and formed in similar loess mantled glacial deposits. Kucera, Lostine, and Marystown soils have less than 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: Greentimber soils are used mainly for irrigated and nonirrigated cropland and farmsteads. The major crops include: seed potatoes, spring barley, winter wheat, and alfalfa hay.
DISTRIBUTION AND EXTENT: These soils are inextensive in southeast Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Fremont County, Idaho, 1985.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - That zone from the surface to 20 inches (Ap and AB horizons).
Argillic horizon - The zone from 20 to 60 inches (Bt, Btb1, and Btb2 horizons).
Particle-size control section - The zone from 20 to 40 inches (Bt and part of the Btb1 horizons).