LOCATION COURTROCK OR+UTEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Calcidic Haploxerolls
TYPICAL PEDON: Courtrock loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 6 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; weak thin platy and fine granular structure; soft, friable, slightly sticky and slightly plastic; common very fine roots; many very fine pores; neutral (pH 7.2); abrupt smooth boundary. (3 to 9 inches thick)
A--6 to 15 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; weak coarse prismatic and weak coarse subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; slightly alkaline (pH 7.6); gradual smooth boundary. (7 to 18 inches thick)
AB--15 to 31 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; soft, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; 10 percent gravel; slightly alkaline (pH 7.8); gradual smooth boundary. (8 to 18 inches thick)
Bk1--31 to 38 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; slightly effervescent with disseminated carbonates; 10 percent gravel; moderately alkaline (pH 8.4); abrupt smooth boundary. (5 to 18 inches thick)
2Bk2--38 to 45 inches; pale brown (10YR 6/3) gravelly loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; strongly effervescent; 20 percent gravel; moderately alkaline (pH 8.4); abrupt smooth boundary. (5 to 24 inches thick)
3C--45 to 50 inches; light brownish gray (10YR 6/2) very gravelly sand, dark grayish brown (10YR 4/2) moist; single grained; loose; carbonate coatings on coarse fragments; 10 percent cobbles and 40 percent gravel; slightly alkaline (pH 7.8).
TYPE LOCATION: Grant County, Oregon; about 7 1/2 miles northeast of Kimberly Oregon; about 1,800 feet west and 2,500 feet south of the NE corner of section 12, T.9S., R.26E. Latitude 44 degrees, 48 minutes, 21 seconds North and Longitude 119 degrees, 32 minutes, 11 seconds West.
RANGE IN CHARACTERISTICS: The soils are dry for one-half to three-fourths of the time (cumulative) when the soil temperature is above 41 degrees F. The mean annual soil temperature is 49 to 55 degrees F. Depth to very gravelly sand ranges from 40 inches to over 5 feet. The particle-size control section is sandy loam, loam, or silt loam and has 10 to 18 percent clay and over 15 percent sand coarser than very fine sand. Rock fragments range from 0 to 25 percent in the upper part and 20 to 35 in the lower part of the control section. Depth to secondary carbonates is 20 to 44 inches. The mollic epipedon is 10 to 20 inches thick.
The Ap and A horizons have value of 4 or 5 dry, chroma of 2 or 3 moist and dry. It has weak platy, granular or subangular blocky structure. It is loam or sandy loam. It has 1 to 5 percent organic matter. It has 8 to 15 percent clay. It has 0 to 25 percent stones, 0 to 15 percent cobbles and 0 to 25 percent gravel. It is neutral or slightly alkaline. It is neutral or slightly alkaline.
The AB horizon has color similar to the A horizon. It has less than one percent organic matter. It is coarse sandy loam or loam. It has 8 to 15 percent clay. It has 0 to 5 percent cobbles and 0 to 25 percent gravel. It is neutral or slightly alkaline.
The Bk and 2Bk horizons have value of 4 to 6 dry, 3 or 4 moist and chroma of 2 or 3 moist and dry. It is loam, silt loam, fine sandy loam or coarse sandy loam with 8 to 18 percent clay. It has 2 to 8 percent calcium carbonate. It has 0 to 5 percent cobbles and 5 to 30 percent gravel.
The 3C horizon, when present, is multicolored sand with 0 to 5 percent clay. It has 35 to 45 percent gravel and 5 to 15 percent cobbles.
COMPETING SERIES: These are the Blue Star, Farrell, Malott, Tickason, and Tonasket series. Blue Star soils have weakly to strongly cemented horizons of lime accumulation at depths of 15 to 30 inches. Farrell soils have 0 to 10 percent rock fragments in the particle-size control section. Tickason soils have a calcic horizon. Tonasket soils have silt loam control sections, have less than 10 percent rock fragments and are underlain by laminated sediments. Malott soils have a duripan at 40 to 60 inches.
GEOGRAPHIC SETTING: Courtrock soils are on alluvial fans at elevations of 1,700 to 6,300 feet. Elevations above 3,400 feet are in Utah. The slopes are 2 to 20 percent. The soils formed in moderately coarse and medium textured alluvium of mixed origin including pumice and ash. Courtrock soils occur in a semiarid climate with hot dry summers and cold moist winters. Mean annual precipitation is 9 to 13 inches. The average July temperature is 70 degrees F., the average January temperature is 32 degrees F., and the mean annual temperature is 45 to 51 degrees F. The frost-free period is 90 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Court, Hack and Luce soils. Court soils have contrasting textures at depths of less than 40 inches. Hack soils have 18 to 27 percent clay in the control section. Luce soils lack mollic epipedon and have 18 to 35 percent clay in the control section.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: These soils are used mainly for the production of irrigated alfalfa-grass hay with some irrigated wheat or barley. Native vegetation is big sagebrush, rabbitbrush, bluebunch wheatgrass and juniper.
DISTRIBUTION AND EXTENT: Courtrock soils occur along the main drainages in east-central Oregon, MLRA 10, and south-central Utah. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Prineville Area, Oregon, 1963.
REMARKS: Diagnostic horizons and other features are:
Mollic epipedon - 0 to 15 inches
Secondary carbonates at 31 inches
Aridic moisture regime