LOCATION MOLCAL WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Vitrandic Calcixerolls
TYPICAL PEDON: Molcal silt loam, idle cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; dark gray (10YR 4/1) silt loam, black (10YR 2/1) moist; weak fine and medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine pores; 10 percent pebbles; calcareous; moderately alkaline (pH 8.2); abrupt smooth boundary. (6 to 10 inches thick)
A--8 to 18 inches; dark grayish brown (10YR 4/2) silt loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many fine roots; many fine pores; 10 percent pebbles; calcareous; moderately alkaline (pH 8.4); clear wavy boundary. (6 to 10 inches thick)
2Bk--18 to 22 inches; light gray (5Y 7/2) silt loam, olive (5Y 5/3) moist; moderate fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; many fine roots; many fine pores; 10 percent pebbles; calcareous; few soft masses of lime; strongly alkaline (pH 8.6); clear wavy boundary. (4 to 8 inches thick)
IICk--22 to 60 inches; light gray (5Y 7/2) gravelly silt loam, olive (5Y 5/3) moist; moderate thin and medium platy structure; hard, firm, slightly sticky and slightly plastic; few fine roots; few fine pores; 20 percent pebbles; organic coatings and thin patchy clay films on the upper surfaces of plates; calcareous; few soft masses of lime; strongly alkaline (pH 8.6).
TYPE LOCATION: Stevens County, Washington; 1,000 feet west of NE corner of section and 100 feet south of Road 226; NE1/4 NE1/4 section 27, T.30N., R.37E.
RANGE IN CHARACTERISTICS: The depth to bedrock is 40 to more than 60 inches. The mean annual soil temperature ranges from 47 to 52 degrees F. The soils are usually moist but are dry in all parts between depths of 8 to 24 inches for 60 to 90 consecutive days. The mollic epipedon ranges from 12 to 20 inches thick. The particle size control section is dominantly silt loam and has more than 15 percent sand coarser than very fine sand and 5 to 35 percent rock fragments.
The A horizon has chroma of 1 or 2. It is loam, silt loam, gravelly loam or gravelly silt loam. This horizon is slightly alkaline or moderately alkaline and in most pedons is calcareous.
The Bk horizon has value of 6 or 7 dry, 4 or 5 moist, and chroma of 1 through. It is silt loam, loam, gravelly silt loam or gravelly loam. This horizon is moderately alkaline or strongly alkaline.
The C horizon has the same ranges as the B horizon except that there are thin organic coatings, and thin patchy clay films on the upper surfaces of the plates. In some pedons the platy structure is lacking and the C horizon is massive.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Molcal soils are on uplands at elevations of 1,400 to 3,000 feet. Slopes are 0 to 65 percent. The soil formed in glacial till, glacial lake sediments and calcareous shale with a component of loess and volcanic ash. The climate is characterized by warm dry summers and cool moist winters. The average annual temperature is 45 to 50 degrees F. and the average annual precipitation ranges from 14 to 20 inches. The frost free season (32 degrees F.) is 100 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the Stevens soils which have a mollic epipedon more than 20 inches thick and lack a calcic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Some areas are under cultivation and alfalfa is the principal crop. Much of the area is rangeland. Native vegetation is bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, rose, scattered ponderosa pine and aspen.
DISTRIBUTION AND EXTENT: Ferry and Stevens Counties, Washington. The Molcal series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Stevens County, Washington, 1971.
REMARKS: The apparent structure in the IIC horizon is probably the result of stratification of parent materials rather than of soil forming processes.