LOCATION PERSAYO CO+NM UT WYEstablished Series
TAXONOMIC CLASS: Loamy, mixed, active, calcareous, mesic, shallow Typic Torriorthents
TYPICAL PEDON: Persayo silty clay loam - grassland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; light yellowish brown (2.5Y 6/3) silty clay loam, light olive brown (2.5Y 5/3) moist; moderate fine granular structure, weak platy in the upper 1/2 inch; soft, very friable; calcareous; moderately alkaline (pH 8.2); gradual smooth boundary. (1 to 7 inches thick)
C--4 to 14 inches; light yellowish brown (2.5Y 6/4) silty clay loam, light olive brown (2.5Y 5/4) moist; weak medium subangular blocky structure parting to moderate fine granules; hard, very friable; few small calcium sulfate crystals; calcareous; moderately alkaline (pH 8.2) gradual smooth boundary. (7 to 14 inches thick)
Cr--14 inches; calcareous gray and yellow shale and siltstone.
TYPE LOCATION: Montrose County, Colorado; 0.1 mile north of the southeast corner of Sec. 22, T. 51 N., R. 10 W.; lat. 38 degrees 39 minutes 56 seconds N. and long. 107 degrees 58 minutes 1 second W., NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture: These soils are dry in all parts of the moisture control section for more than three-fourths of the time that the soil temperature is above 41 degrees F. The soil moisture control section is usually dry, but intermittently moist during late summer and early fall. Aridic moisture regime.
Mean annual soil temperature: 47 to 58 degrees F.
Mean summer soil temperature: 60 to 75 degrees F.
Depth to paralithic contact: 4 to 20 inches.
Organic carbon: approximately .4 percent; ranges to 0.9 percent.
The sand/clay ratio: less than 1 to about 3.
Exchangeable sodium: typically less than 3 percent, but tends to increase as depth increases and differs among pedons.
Calcium carbonate equivalent: 3 to 20 percent
Calcium sulfate: less than 1 to about 10 percent.
Particle-size control section (weighted average): Texture: silt loam, loam, clay loam, or silty clay loam
Clay content: 18 to 35 percent
Silt content: 30 to 65 percent
Sand content: 5 to 45 percent
Coarse fragments: 0 to 35 percent.
A horizon
Hue: 10YR to 5Y
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 2 through 4
Reaction: slightly to strongly alkaline
Consistence: soft to slightly hard.
C horizon
Hue: 10YR through 5Y
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 2 through 4
Reaction: slightly alkaline to strongly alkaline
It contains some visible calcium carbonate and gypsum which are not concentrated into a definite horizon of secondary accumulation and are considered to be characteristics of the parent sediments rather than pedogenic.
Some pedons are overlain by sedimentary colluvium, and a 2C horizon derived from shale residuum is present.
COMPETING SERIES: These are the Poncho (T) and Shalet series. Poncho and Shalet soils have hues of 7.5YR or redder.
GEOGRAPHIC SETTING: These soils are on upland hills, terraces, ridges and scarps. Slopes range from 1 to 50 percent. The soil formed in thin sediments weathered from underlying soft sedimentary bedrock, and in colluvium and/or slope alluvium over residuum weathered from sandstone and shale. Elevation ranges from 5,000 to 6,800 feet. At the type location mean annual precipitation is 7 to 11 inches with peak periods of precipitation occurring from July to October; driest months are December and June. Mean annual temperature ranges from 47 to 53 degrees F., and mean summer temperature is about 66 to 70 degrees F. Frost-free period ranges from 95 to 150 days. In Utah this soil has a mean annual precipitation of 6 to 9 inches, mean annual temperature of 45 to 50 degrees, and a frost-free season of 115 to 160 days at an elevation of 4,000 to 6,200 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chipeta and Menoken soils. Chipeta soils have more than 35 percent clay in the series control section. Menoken soils lack bedrock above a depth of 20 inches and have cambic horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium to high runoff; moderate or moderately slow permeability.
USE AND VEGETATION: These soils are used almost exclusively for native pastureland. Native vegetation is salt sage, greasewood, shadscale, and scattered grasses.
DISTRIBUTION AND EXTENT: Western Colorado and Wyoming, northwestern New Mexico, and eastern Utah. The series is of large extent. MLRA 34B and 35.
MLRA OFFICE RESPONSIBLE: Lakewood, Colorado
SERIES ESTABLISHED: Western Colorado Reconnaissance, W95, 1939.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 0 to 14 inches (A and C horizons)
Ochric epipedon: The zone from 0 to 4 inches.
Paralithic contact: The contact with shale and siltstone at about 14 inches.
In the future the Persayo series will be limited to Colorado, New Mexico, and Utah
Classified according to Keys to Soil Taxonomy Tenth Edition, 2006