LOCATION MCKINNEY WYTentative Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous Typic Cryaquents
TYPICAL PEDON: McKinney loam
A1--0 to 6 inches; gray (10YR 5/1 dry) loam, dark gray (10YR 4/1) moist; weak medium subangular blocky structure breaking to moderate very fine granules; slightly hard dry, very friable moist; approximately 5 percent gravel, much of which is scattered on the surface; calcareous, pH 8.2; clear smooth boundary. 4 to 8 inches thick.
C1--6 to 12 inches; gray (2.5Y 5/1 dry) loam, dark gray (2.5Y 4/1) moist; moderate medium subangular blocky structure; hard dry, very friable moist; 5 percent gravel; calcareous, pH 8.4; gradual wavy boundary. 4 to 12 inches thick.
C2cag--12 to 30 inches; light gray (2.5Y 7/2 dry) loam, grayish-brown (2.5Y 5/2) moist; massive; hard dry, very friable moist; 5 percent gravel; common numbers of medium-sized distinct 10YR 3/4 mottles; this is a moderate ca horizon with visible calcium carbonate occurring in finely divided forms; calcareous, pH 8.4; gradual wavy boundary. 8 to 24 inches thick.
C3cag--30 to 60 inches; light brownish-gray (2.5Y 6/2 dry) loam, grayish-brown (2.5Y 5/2) moist; massive; hard dry, very friable moist; 5 percent gravel; common numbers of medium-sized distinct 10 YR 4/4 mottles; a moderate ca horizon with some visible calcium carbonate occurring as concretions, and in thin seams and streaks; calcareous, pH 8.4. Several feet thick.
TYPE LOCATION: 0.1 mile west of highway 189 and 0.1 mile north of Horse Creek bridge, Sublette County, Wyoming.
RANGE IN CHARACTERISTICS: Color of the A1 horizon may range in hue from 10YR to 2.5Y, in chroma from 1 to 2, and in value from 5 to 6 dry and 4 to 5 moist. Hue of the Ccag horizon ranges from 5Y to 10YR. These soils should have mottling above 20 inches. Reaction of the control section ranges from pH 8.0 to pH 8.6. Content of organic carbon ranges from .7 to 1.5 percent in the upper 15 inches and decreases regularly with depth. Conductivity ranges from less than 1 to 3 millimhos in the control section. Calcium carbonate equivalent of the strongest part of the Cca horizon is typically about 10 percent but may range from 6 to 14 percent with the content of calcium carbonate decreasing with depth. Exchange capacity ranges from 8 to 20 milliequivalents per 100 grams of soil in the control section. Exchangeable sodium ranges from less than 1 in the surface horizon to 1 to 5 percent in the Cca horizon. Exchangeable sodium increases with depth. Texture of the control section is typically a loam but may range in clay from 18 to 35 percent, in silt from 20 to 55 percent, and in sand from 20 to 50 percent. content of coarse fragments ranges from 0 to 15 percent in the control section. There should be no bedrock or strongly contrasting substratums above 40 inches in these soils.
COMPETING SERIES: There are no series known to compete with this series in the name subgroup and family. Similar soils in the same subgroup but a different family is the Juvan series which differs in having silty textures with less than 15 percent fine sand or coarser.
GEOGRAPHIC SETTING: The McKinney soils occur on flood plains or low terraces bordering streams that drain sedimentary beds. Slope gradients range from 0 to 6 percent. They are developing in alluvial fan materials. At the type location the average annual precipitation is 15 inches, most of which falls in the spring and summer months. Average annual soil temperature is 37 degrees F., and the average summer soil temperature is 58 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the Juvan and Newfork series.
DRAINAGE AND PERMEABILITY: Moderately well to imperfectly drained. Runoff is slow, and permeability is moderate. Fluctuating ground-water tables occur in these soils at some season of the year.
USE AND VEGETATION: These soils are used mainly as native pastureland or as wild hay meadow. Native vegetation includes slender wheatgrass, mat muhly, and some short grass.
DISTRIBUTION AND EXTENT: Present known distribution limited to the Pinedale area. The series is expected to be of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: The Standard Soil Survey of Sublette County, Wyoming, 1965.
REMARKS: Series name taken from the name of a local ranch in the vicinity of the type location.
OSED scanned by NSSQA. Last revised by state on 3/65.