LOCATION CHAFIN NMEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ustic Haplargids
TYPICAL PEDON: Chafin clay loam - rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 1 inch; pale yellow (2.5Y 7/3) clay loam, light olive brown (2.5Y 5/3) moist; weak fine granular structure; slightly hard, friable, slightly sticky and moderately plastic; common very fine and fine roots; very slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary. (1 to 4 inches thick)
Bt1--1 inch to 8 inches; pale yellow (2.5Y 7/3) clay, light olive brown (2.5Y 5/3) moist; weak fine, medium and coarse subangular blocky structure; hard, friable, moderately sticky and very plastic; few very fine and fine roots; common distinct clay films on faces of ped; very slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary.
Bt2--8 to 32 inches; light yellowish brown (2.5Y 6/3) clay, olive brown (2.5Y 4/3) moist; weak very fine and fine subangular blocky structure; very hard, firm, moderately sticky and very plastic; few very fine and fine roots; common distinct clay films on faces of ped; very slightly effervescent; slightly alkaline (pH 7.6); clear smooth boundary. (The combined thickness of the Bt horizons is 12 to 31 inches thick)
C1--32 to 55 inches; light yellowish brown (2.5Y 6/3) clay loam, light olive brown (2.5Y 5/3) moist; weak fine and medium subangular blocky structure intermingled with massive; slightly hard, friable, slightly sticky and very plastic; very slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary. (10 to 23 inches thick)
2C2--55 to 60 inches; pale yellow (2.5Y 7/3) loamy sand, light olive brown (2.5Y 5/3) moist; massive; loose, nonsticky and nonplastic; very slightly effervescent; slightly alkaline (pH 7.6).
TYPE LOCATION: McKinley County, New Mexico; Tohatchi Quadrangle; UTM's: 6-95-861 W. and 39-62-670 N.; T. 18 N, R. 19 W, sec. 14; 108 degrees, 49 minutes, 58 seconds west longitude; 35 degrees, 47 minutes, 19 seconds north latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: Intermittently moist in some part of the soil moisture control section during July through October and December through March. Driest during May and June. Ustic aridic soil moisture regime
Soil Temperature: 52 to 55 degrees F.
Base of the argillic horizon: 16 to 32 inches
Particle size control section
Clay content: 35 to 50 percent
Rock fragments: 0 to 5 percent sandstone gravel
Reaction: slightly alkaline to strongly alkaline
Calcium carbonate equivalent: 1 to 5 percent in the particle size control section and is disseminated.
Gypsum: 0 to 2 percent
Salinity, EC: 0 to 2 dS/m
Sodicity, SAR: 0 to 2
A horizon
Hue: 10YR, 2.5Y
Value: 5 to 7 dry, 3 to 5 moist
Chroma: 2 to 4, dry or moist
Bt horizons
Hue: 10YR, 2.5Y
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 4, dry or moist
Texture: clay loam, silty clay loam, silty clay, clay
C horizons
Hue: 10YR, 2.5Y
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 2 to 4, dry and moist
Texture: very fine sandy loam, loam, clay loam, sandy clay loam, loamy sand
Other features: Due to the position of this soil on the landscape, textures in the C horizons can be highly variable.
COMPETING SERIES: These are the Hawaikuh (NM), Lonti (AZ), Mags (T)(CO), Padilla (AZ), Servilleta (NM), Silver (NM) and Tobish (UT) soils. Hawaikuh, Lonti, and Padilla soils have hue redder than 7.5YR. Lonti soils average more than 15 percent rock fragments in the particle size control section and do not have secondary calcium carbonate in the argillic horizon. Mags soils have secondary calcium carbonate in the lower part of the argillic horizon. Servilleta and Tobish soils are moderately deep to a lithic contact. Silver soils have more than 15 percent calcium carbonates below 40 inches.
GEOGRAPHIC SETTING: The Chafin soils are on fan terraces on valley sides and on summits of mesas. Slope ranges from 1 to 15 percent. They formed in fan alluvium derived from sandstone and shale. Mean annual air temperature ranges from 50 to 53 degrees F. and mean annual precipitation ranges from 10 to 14 inches. The majority of the annual precipitation falls as high-intensity convective thunderstorms between July and September with May and June being the driest months. The frost-free period is 120 to 150 days and elevation is 5,600 to 7,800 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nahodish, Barx, and Yenlo soils. Nahodish soils are on stream terraces and do not have argillic horizons. Barx and Yenlo soils are medium textured on fan terraces.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderately slow and slow. Runoff is medium to high.
USE AND VEGETATION: The principal use of these soils is livestock grazing. Present vegetation is blue grama, galleta, sideoats grama, and threeawn with widely spaced pinyon and juniper at the upper end of the precipitation zone.
DISTRIBUTION AND EXTENT: West-central New Mexico and eastern Arizona. MLRA 35, LRR-D. This soil is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Fort Defiance Area, Parts of Apache and Navajo Counties Arizona, and McKinley and San Juan Counties, New Mexico; 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 1 inch (A horizon)
Argillic horizon - the zone from 1 to 32 inches (Bt horizons)
Soils classified according to Soil Taxonomy, Second Edition, 1999; Keys to Soil Taxonomy, Tenth Edition, 2006