LOCATION DREWS OR+CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Argixerolls
TYPICAL PEDON: Drews loam--rangeland. (Colors are for moist soil unless otherwise noted.)
A--0 to 6 inches; very dark brown (10YR 2/2) loam, dark gray (10YR 4/1) dry; weak very thin platy structure parting to weak very fine granular; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine pores; 5 percent gravel; slightly acid (pH 6.5); gradual wavy boundary. (5 to 10 inches thick)
AB--6 to 11 inches; very dark brown (10YR 2/2) loam, dark grayish brown (10YR 4/2) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; 5 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (0 to 10 inches thick)
Bt1--11 to 16 inches; very dark grayish brown (10YR 3/2) clay loam, grayish brown (10YR 5/2) dry; weak medium prismatic structure parting to weak medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; few faint clay films on peds and in pores; 10 percent gravel; slightly acid (pH 6.4); clear wavy boundary. (4 to 10 inches thick)
Bt2--16 to 27 inches; dark brown (10YR 3/3) gravelly clay loam, brown (10YR 5/3) dry; weak medium prismatic structure parting to moderate medium and fine angular blocky; hard, firm, sticky and plastic; common very fine roots; many very fine tubular pores; common distinct clay films on peds, faint clay films in pores; 25 percent gravel; neutral (pH 6.6); gradual smooth boundary. (8 to 15 inches thick)
BC--27 to 36 inches; dark brown (10YR 3/3) gravelly clay loam, pale brown (10YR 6/3) dry; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 30 percent gravel; neutral (pH 6.6); gradual smooth boundary. (9 to 12 inches thick)
C--36 to 60 inches; dark yellowish brown (10YR 3/4) very gravelly loam, pale brown (10YR 6/3) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; 40 percent gravel; neutral (pH 6.8).
TYPE LOCATION: Lake County, Oregon; about 10 miles west of the town of Lakeview; about 1,400 feet north and 1,280 feet east of the southwest corner of section 17, T. 39 S., R. 19 E.; USGS Drews Gap 7.5 minute topographic quadrangle; approximately 42 degrees 11 minutes 0 seconds north latitude and 120 degrees 30 minutes 27 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 50 degrees F. Soils are usually moist and are dry in all parts between depths of 4 to 12 inches about 90 to 115 consecutive days following the summer solstice. The soils are moist in the winter. The solum is 30 to 60 inches thick. Depth to bedrock is 60 inches or more. Siltstone and duripans occur at depths of 40 to 60 inches in some pedons. The mollic epipedon is 20 to 40 inches thick.
The A horizon has value of 2 or 3 moist, 3 or 4 dry and chroma of 1 or 2 moist and dry. It has 0 to 35 percent coarse fragments, dominantly gravel size. It is slightly acid or neutral.
The Bt and BC horizons have hue of 10YR or 7.5YR, value of 2 to 4 moist, 4 to 6 dry, and chroma of 2 or 3 moist and dry. It is clay loam or sandy clay loam with 27 to 35 percent clay and 0 to 35 percent gravel. It has weak prismatic, subangular, or angular blocky structure. It is slightly acid or neutral.
COMPETING SERIES: These are the Banning, Coolbrith, Dotta, Gorman, Harriman, Haysum, Robinette, Supan, Van Dusen, Waha, Wapinitia, and Yaxon series.
Banning soils are dry for 45 to 90 consecutive days, are somewhat poorly drained with mottles in the A and upper B horizons and have a mean annual soil temperature of 52 to 56 degrees F. Coolbrith soils are somewhat poorly drained and have mottles in the lower B horizons. Dotta soils have 18 to 27 percent clay in the Bt horizons and have sandy clay loam to coarse sand C horizons. Gorman soils have 20 to 28 percent clay in the Bt horizon, have 15 to 25 percent coarse and very coarse sand in the A and B horizons and have a mean annual temperature of about 57 degrees F. Harriman soils are usually dry. Haysum soils have a mean annual soil temperature of 52 to 59 degrees F. and are dry for 85 to 95 consecutive days. Robinette soils have a silt loam loess mantle, and the top of the argillic horizon is below 40 inches. Supan soils have mean annual soil temperature warmer than 55 degrees F. Van Dusen soils have considerable mica and coarse and very coarse sand grains of quartz. Waha soils have bedrock at depths of 20 to 40 inches. Wapinitia soils have silty clay loam Bt horizons having hard noncalcareous nodules and formed in loess and ash. Yaxon soils are dry for 75 to 90 consecutive days.
GEOGRAPHIC SETTING: Drews soils are on terraces, terraces escarpments, and fans at elevations of 4,500 to 5,000 feet. Slopes range from 0 to 35 percent. The soils formed in old gravelly alluvium weathered from rhyolite, tuff, and basalt. The mean annual precipitation is 13 to 18 inches. The mean July temperature is 65 to 68 degrees F., the mean January temperature is 27 to 29 degrees F., and the mean annual temperature is 46 to 49 degrees F. The frost-free period is 70 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Deter, Oxwall, and Salisbury soils. These soils have clayey Bt horizons. Also, Oxwall and Salisbury soils have a duripan.
DRAINAGE AND PERMEABILITY: Well drained; moderately slow permeability. If the soils are over-irrigated a water table may develop at 3.5 to 6.0 feet.
USE AND VEGETATION: Drews soils are used for irrigated and dryland crops, livestock grazing, homesites, and wildlife. Native plants are mainly mountain big sagebrush, antelope bitterbrush, bluebunch wheatgrass, and Idaho fescue.
DISTRIBUTION AND EXTENT: South-central Oregon and northeastern California. These soils are moderately extensive. MLRA 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Modoc County (Alturas Area), California, 1974.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 27 inches (A, AB, Bt1, and Bt2 horizons).
Argillic horizon - The zone from 11 to 27 inches (Bt1 and Bt2 horizons).
ADDITIONAL DATA: A pedon of Drews has characterization data from the soil survey laboratory, Lincoln, NE as soil survey sample number S79OR-037-002 (pedon # 79P0426). This data is not from the series type location.
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data.