LOCATION MARGERUM WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Argixerolls
TYPICAL PEDON: Margerum gravelly silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; grayish brown (10YR 5/2) gravelly silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; common roots; 18 percent pumice; slightly acid (pH 6.2); clear smooth boundary. (6 to 8 inches thick)
A12--7 to 14 inches; grayish brown (10YR 5/2) gravelly silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; common roots; 18 percent pumice; slightly acid (pH 6.3); clear smooth boundary. (6 to 8 inches thick)
A3--14 to 24 inches; pale brown (10YR 6/3) gravelly silt loam, dark brown (10YR 4/3) moist; weak fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic; common roots; patchy thin cutans (may be clay films) on surfaces of peds; 30 percent pumice; neutral (pH 6.6); clear wavy boundary. (8 to 12 inches thick)
B1--24 to 35 inches; pale brown (10YR 6/3) gravelly silt loam, dark brown (10YR 4/3) moist; weak fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic; common roots; patchy thin cutans (may be clay films) on surfaces of ped; 30 percent pumice; neutral (pH 6.6); clear wavy boundary. (8 to 12 inches thick)
B2t--35 to 44 inches; light yellowish brown (10YR 6/4) gravelly clay loam, dark yellowish brown (10YR 4/4) moist; moderate very fine subangular blocky structure; very hard, firm, sticky, plastic; few roots; common very thin and thin clay films in pores, common very thin clay bridges between mineral grains, and few thin clay films on surfaces of peds; 20 percent pumice; neutral (pH 6.8); clear wavy boundary. (8 to 12 inches thick)
C--44 to 60 inches; pale brown (10YR 6/3) silt loam, dark brown
(10YR 4/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky, slightly plastic; few roots; 10 percent pumice; neutral (pH 7.0).
TYPE LOCATION: Chelan County, Washington; half way up ridge above small draw on the Swanson farm in the SE1/4 NW1/4, sec. 21, T.28N., R.22E. Slope is 11 percent.
RANGE IN CHARACTERISTICS: The solum is 40 to 52 inches thick. Mean annual soil temperature at 20 inches ranges from 50 to 55 degrees F. These soils are usually dry between depths of 4 and 12 inches. The mollic epipedon is 12 to 16 inches thick. Content of coarse fragments (dominantly pumice) in the control section ranges from 15 to 35 percent.
The A1 horizon has value of 4 or 5 dry and 2 or 3 moist, medium granular structure. It is neutral or slightly acid. The B2 horizon has value of 4 through 6 dry and 3 or 4 moist, and chroma of 3 or 4 dry or moist. It is gravelly clay loam to gravelly silt loam. This horizon has weak to moderate blocky or prismatic structure. It is neutral or mildly alkaline.
The C horizon has the same color range as the B2 horizon. It is silt loam or gravelly silt loam. This horizon is massive or has weak structure. It is neutral or mildly alkaline. Some pedons contain thin lenses with more than 50 percent pumice.
COMPETING SERIES: These are the Bjork, Colma, Cowiche, Dragoon, Elmore, Galeppi, Glenrose, Indiano, Lobitos, Los Gatos, Melhorn, Sallyann, Schumacher, Simcoe, Sweeney, and Tieton series. Bjork soils have bedrock at depth of less than 40 inches. Colma, Dragoon, Galeppi, Glenrose, Lobitos, Los Gatos, Melhorn, Schumacher, and Sweeney soils are usually moist. Cowiche, Simcoe, and Tieton soils have less than 15 percent coarse fragments in the control section. Elmore soils have secondary carbonates within depth of 43 inches. Indiano soils have bedrock at depth of 20 to 33 inches. Sallyann soils have base saturation of less than 75 percent. Springmeyer soils have sola 20 to 28 inches thick.
GEOGRAPHIC SETTING: These soils are on nearly level to steep uplands at elevations of 1,800 to 2,800 feet. They formed in loess containing 20 to 40 percent ash and pumice, deposited over nonsorted glacial drift or acid igneous bedrock. The climate is semiarid; summers are hot and dry and winters are moist and cold. Mean annual precipitation is 9 to 13 inches. Mean January temperature is 37 degrees F.; mean July temperature is 62 degrees F.; mean annual temperature is about 48 degrees to 50 degrees F.; and average frost-free season is 160 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chelan and Alstown soils. The Chelan soils contain 60 to 90 percent pyroclastics in the control section, formed in nonsorted gravelly or cobbly glacial drift deposits and occur below the Margerum soils. Alstown soils have a lower pumice content and are underlain with basic igneous bedrock.
DRAINAGE AND PERMEABILITY: Well-drained; very slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Mostly in dryland cereal grains and forage production. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, sagebrush, and scattered ponderosa pine vegetation.
DISTRIBUTION AND EXTENT: Northcentral Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington, 1969.
REMARKS: These soils were formerly classified as Brown soils intergrading to Chestnut soils.