LOCATION NELSON CO+MT WYEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, calcareous, mesic Ustic Torriorthents
TYPICAL PEDON: Nelson fine sandy loam - cultivated. (Colors are for dry soil unless otherwise noted.)
Alp--0 to 9 inches; light brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure that parts to moderate fine granules; slightly hard, very friable; calcareous; moderately alkaline (pH 8.2); abrupt smooth boundary. (6 to 12 inches thick)
C1ca--9 to 30 inches; light olive brown (2.5Y 5/4) fine sandy loam, olive brown (2.5Y 4/4) moist; massive; hard, very friable; visible secondary calcium carbonate occurring as concretions and in thin seams and streaks; moderately alkaline (pH 8.2); gradual wavy boundary. (8 to 34 inches thick)
C2--30 to 60 inches; calcareous soft sandstone and interbedded loamstone.
TYPE LOCATION: Weld County, Colorado; approximately 2,000 feet south and 2,450 feet east of the NW corner of Sec. 17, T. 6 N., R. 66 W.
RANGE IN CHARACTERISTICS: These soils are typically calcareous throughout but are leached for a few inches in some pedons. Depths to the soft sandstone and interbedded loamstone ranges from 20 to 40 inches. Organic carbon of the upper 15 inches is approximately 5 percent and the sand/clay ratio typically ranges from 5 to 8. Mean annual soil temperature ranges from 49 to 58 degrees F., and mean summer soil temperature ranges from 65 to 75 degrees F. Rock fragments are typically less than 10 percent and range from 0 to 15 percent.
The A horizon has hue of 2.5Y or 10YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 3. When the value of the surface horizon is as dark as 5 dry and 3 moist the horizon is too thin to be mollic. Typically, the A horizon has fine granular structure but it may have weak subangular blocky structure when tilled. It is soft to slightly hard. This horizon is mildly to strongly alkaline (pH 7.8 to 8.6).
The C1ca horizon has hue of 2.5Y through 7.5YR, dependent upon the lithochromic coloration of bedrock itself. It is moderately to strongly alkaline (pH 8.0 to pH 8.6) and has approximately 1 to 8 percent calcium carbonate equivalent.
COMPETING SERIES: These are the Nelman, Otero, Pedrick, and Shedado series. Nelman and Shedado soils have a lithic contact at depths of 20 to 40 inches. Otero and Pedrick soils lack a paralithic contact at depths of 20 to 40 inches.
GEOGRAPHIC SETTING: These soils are on gently to moderately sloping upland hills and ridges. Slope gradients range from about 2 to 12 percent. The soils formed in moderately coarse textured calcareous parent materials weathered residually from underlying sedimentary bedrock. At the type location the average annual precipitation is approximately 14 inches with peak periods of precipitation occurring during the spring and early summer months. The mean annual temperature is 48 degrees F., and the mean summer temperature is 70 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Tassel and Shingle soils and the competing Otero soils. Nelson soils form a toposequence with the soils of the Tassel and Otero series in some areas. Tassel and Shingle soils have a paralithic contact at depths of 10 to 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately rapid permeability.
USE AND VEGETATION: Used as rangeland. Principal native vegetation is blue grama, sideoats grama, sand reedgrass, yucca, and cactus.
DISTRIBUTION AND EXTENT: Colorado, Montana, and Wyoming. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Western Colorado Reconnaissance Survey, 1939.
REMARKS: Last updated by the state 4/73.