LOCATION CHESNIMNUS OREstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Calcic Argixerolls
TYPICAL PEDON: Chesnimnus silt loam, cultivated, on a 2 percent slope at an elevation of 4010 feet. When described on July 23, 1964 the soil was moist throughout. Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate thin platy structure parting to weak very fine granular; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many very fine tubular pores; neutral (pH 6.8); abrupt smooth boundary. (6 to 10 inches thick)
Bt--7 to 13 inches; dark brown (10YR 3/3) clay loam, brown (10YR 4/3) dry; moderate medium prismatic structure parting to weak medium subangular blocky; hard, firm, moderately sticky and moderately plastic; many fine roots; many very fine tubular pores; many distinct clay films on ped faces; slightly alkaline (pH 7.4); clear wavy boundary. (4 to 13 inches thick)
Bk1--13 to 26 inches; brown (10YR 4/3) clay loam, brown (10YR 5/3) dry; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine roots; many very fine tubular pores; 5 percent gravel; strongly effervescent; segregated lime in common 2 to 5 mm soft masses; moderately alkaline (pH 8.2); clear wavy boundary. (12 to 20 inches thick)
Bk2--26 to 34 inches; brown (10YR 4/3) clay loam, pale brown (10YR 6/3) dry; weak fine and medium platy structure; hard, firm, moderately sticky and moderately plastic; common fine roots; many very fine tubular pores; 5 percent gravel; strongly effervescent with disseminated lime; moderately alkaline (pH 8.2); clear wavy boundary. (8 to 12 inches thick)
Bk3--34 to 48 inches; pale brown (10YR 6/3) loam, very pale brown (10YR 7/3) dry; massive; slightly hard, friable, nonsticky and nonplastic; few fine roots; many very fine tubular pores; 10 percent gravel; strongly effervescent with disseminated lime; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 15 inches thick)
2Bk4--48 to 60 inches; pale brown (10YR 6/3) very gravelly sandy loam, very pale brown (10YR 7/3) dry; massive; soft, friable, nonsticky and nonplastic; many fine and medium irregular pores; 40 percent lime coated gravel; strongly effervescent; moderately alkaline (pH 8.2).
TYPE LOCATION: Wallowa County, Oregon; about 3 miles southeast of Enterprise, Oregon; 1500 feet east and 150 feet south of the NW corner of section of 9, T. 2 S., R. 45 E. (Latitude 45 degrees, 24 minutes, 38 seconds N, Longitude 117 degrees, 12 minutes, 08 seconds W)
RANGE IN CHARACTERISTICS: The soils are usually moist, but are dry in all parts of the moisture control section for 60 to 90 consecutive days during the summer. The mean annual soil temperature is 44 to 47 degrees F. Depth to the very gravelly substratum is 35 to 50 inches. Thickness of the mollic epipedon is 10 to 20 inches. Depth to carbonates is 10 to 23 inches. Depth to bedrock is 60 inches or more. The mean annual soil temperature is 44 to 47 degrees F.
The Ap horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 or 2 moist and dry. The texture is silt loam or loam with 0 to 25 percent gravel.
The Bt horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 3 or 4 moist and dry. The texture is clay loam or silty clay loam, with 0 to 25 percent gravel. It has 27 to 35 percent clay.
The Bk1 and Bk2 horizons have value of 3 or 4 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. The texture is clay loam or silty clay loam, with 0 to 25 percent gravel. They have 0 to 5 percent CaCO3.
The Bk3 horizon, when present, has value of 4 to 6 moist, 5 to 7 dry, and chroma of 3 or 4 moist and dry. The texture is loam, clay loam, or gravelly clay loam with 0 to 25 percent gravel. It has 10 to 15 percent CaCO3.
The 2Bk4 horizon has color similar to the Bk3 horizon. The texture is loam, sandy loam, or loamy sand. It has 30 to 60 percent gravel and 0 to 15 percent cobbles. It has 25 to 30 percent CaCO3 equivalent.
COMPETING SERIES: These are the Border (T), Justesen, McCarey, Pegram (T), Vicking, and Victon (T) series. Border and Pegram soils have gravelly Bt horizons with hues of 7.5YR and 5YR. Justesen soils are 36 to 44 inches deep to carbonates. McCarey soils have bedrock at depths of 20 to 40 inches. Vicking soils have an argillic horizon that hue ranging to 7.5YR and a solum thickness of 18 to 33 inches. Victon soils have bedrock at a depths of 40 to 60 inches.
GEOGRAPHIC SETTING: The Chesnimnus soils are on outwash plains. They formed in glacial outwash and have an influence of loess and volcanic ash in the surface horizons. Slope is 0 to 3 percent. The elevation is 3600 to 4400 feet. The mean annual precipitation is 13 to 17 inches. The mean annual temperature is 42 to 45 degrees F. The mean frost-free period is 70 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Reavis, Redmount, and Silverlake series. These soils are all on outwash plains. Reavis soils lack an argillic horizon. Redmount soils are coarse-loamy and lack both an argillic horizon and a Bk horizon. Silverlake soils are fine family and have a strongly cemented duripan below 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability.
USE AND VEGETATION: Chesnimnus soils are used mainly for irrigated hay and pasture, and small grains. The potential native vegetation is predominantly Idaho fescue and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northeastern Oregon, MLRA 9. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wallowa County, Oregon, 1998.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
mollic epipedon - from the surface to 13 inches (Ap and Bt horizons).
calcic feature - from 13 to 26 inches (Bk1 horizon) segregated soft calcium carbonate masses.
argillic horizon - from 7 to 13 inches (Bt horizon)
particle-size control section - from 7 to 13 inches (the argillic horizon)
ADDITIONAL DATA: Characterization data on two profiles (S64Oreg-32-10 and 11) reported in "Riverside Soil Survey Laboratory Report for soils from Wallowa County, Oregon", July 1966.