LOCATION HESSELTINE WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Hesseltine silt loam, woodland. (Colors are for dry soil unless otherwise stated.)
O--1/2 inch to 0; very dark grayish brown, partially decomposed litter composed of pine needles, leaves, twigs, and cones; medium acid (pH 5.8); abrupt smooth boundary.
A1--0 to 3 inches; brown (10YR 5/3) silt loam, dark brown (7.5YR 3/2) moist; weak medium platy structure parting to moderate fine granular; slightly hard, friable, slightly sticky and slightly plastic; many roots; slightly acid (pH 6.5); clear smooth boundary. (3 to 8 inches thick)
A3--3 to 6 inches; brown (10YR 5/3) silt loam, dark brown (7.5YR 3/3) moist; weak medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; many roots; many very fine pores; few pebbles and cobbles; neutral (pH 6.7); clear smooth boundary. (2 to 6 inches thick)
B21t--6 to 13 inches; brown (7.5YR 5/4) silt loam, dark brown (7.5YR 3/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; many roots; many very fine and few fine and medium pores; common thin clay films on faces of peds and in pores; few pebbles and cobbles; neutral (pH 6.7); clear wavy boundary. (6 to 12 inches thick)
B22t--13 to 17 inches; brown (7.5YR 5/4) very gravelly loam, dark brown (7.5YR 4/3) moist; moderate fine subangular blocky structure; hard, firm, sticky and plastic; many roots; many very fine pores; common thin clay films on peds and in pores; few clean mineral grains on surfaces of peds; 40 percent pebbles, 10 percent cobbles; neutral (pH 6.8); abrupt wavy boundary. (3 to 8 inches thick)
IIC1--17 to 36 inches; multicolored reddish brown to olive brown very gravelly coarse sandy loam; single grained; loose; 45 percent pebbles, 10 percent cobbles and 2 percent stones; patchy thin clay films on pebbles and cobbles; few roots; neutral (pH 7.0); gradual wavy boundary. (12 to 20 inches thick)
IIC2--36 to 60 inches; multicolored reddish brown to olive brown extremely gravelly loamy coarse sand; single grained; loose; 50 percent pebbles, 20 percent cobbles, 5 percent stones; few roots in upper few inches; neutral (pH 7.0).
TYPE LOCATION: Spokane County, Washington; 75 feet south of Cornwall Road between two blazed pine trees in the NE1/4 NW1/4 sec. 32, T.23N., R.40E.
RANGE IN CHARACTERISTICS: Solum thickness and depth to the discontinuity range from 14 to 30 inches. these soils are usually moist, but are dry in all part between depths of 8 and 24 inches for 60 to 80 consecutive days during the summer and autumn. Mean annual soil temperature is 47 degrees to 52 degrees F. The mollic epipedon is 7 to 14 inches thick. The soils are slightly acid or neutral.
The A1 horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 moist and dry. It is silt loam or loam and is modified by pebbles, cobbles or stones in some pedons.
The B2t horizon has hue of 10YR, 7.5YR or 5YR, value of 3 through 5 moist, 4 or 5 dry, and chroma of 3 or 4 moist and dry. It is silt loam or loam and averages 10 to 18 percent clay. The upper part has 0 to 15 percent rock fragments and the lower part 25 to 50 percent. The weighted average of rock fragments in the argillic horizon ranges from 15 to 35 percent.
The C horizon below depth of 30 inches as moderately coarse to coarse texture and has 35 to 90 percent rock fragments.
COMPETING SERIES: These are the Kitchen Creek series in the same family and the Badenaugh, Dragoon, Ridd, and Tekoa series. Badenaugh and Dragoon soils have more than 18 percent clay in the B2t horizon. Kitchen Creek soils lack coarse fragments in the profile. Ridd soils have a lithic contact at a depth of 25 to 40 inches. Tekoa soils have bedrock at a depth of less than 40 inches.
GEOGRAPHIC SETTING: Hesseltine soils are on glacial outwash plains at elevations of 2,000 to 3,000 feet. Slopes are 0 to 35 percent. These soils formed in glacial outwash with a thin mantle of loess. They occur in a continental climate having dry summers and cool, moist winters. Mean annual precipitation is 17 to 20 inches. Average January temperature is 25 degrees F., average July temperature is 68 degrees F., mean annual temperature is 47 degrees F. The frost-free season is 90 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cheney, Tucannon, and Uhlig soils. Cheney and Uhlig soils lack an argillic horizon. Tucannon soils have a lithic contact at a depth of 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability in the B horizon, and very rapid permeability in C horizon.
USE AND VEGETATION: Primarily woodland and range. Some areas are used for the production of small grains, alfalfa, grass, and seeded pasture. Native vegetation is ponderosa pine, Idaho fescue, beardless wheatgrass, prairie junegrass, Sandberg bluegrass and yarrow.
DISTRIBUTION AND EXTENT: Eastern Washington. Series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Spokane County, Washington, 1917.