LOCATION TUNTSA NM+AZEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Pachic Haplustolls
TYPICAL PEDON: Tuntsa fine sandy loam -- on a footslope between ridges of a stable landslide, sloping 13 percent to the west at 8,480 feet elevation -- rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; very dark grayish brown (10YR 3/2) fine sandy loam, very dark brown (10YR 2/2) moist; moderate medium platy structure parting to moderate medium granular; soft, very friable, slightly sticky and nonplastic; few fine and many very fine roots; common very fine irregular pores; neutral; abrupt smooth boundary. (2 to 4 inches thick)
BA--3 to 9 inches; very dark gray (10YR 3/1) fine sandy loam, black (10YR 2/1) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine and few fine roots; few fine tubular pores and common very fine interstitial pores; 5 percent pebbles; neutral; clear smooth boundary. (6 to 10 inches thick)
Bw1--9 to 24 inches; very dark gray (10YR 3/1) fine sandy loam; black (10YR 2/1) moist; moderate coarse subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; few fine and many very fine roots; few fine and common very fine tubular pores; 5 percent pebbles; neutral; gradual smooth boundary. (6 to 16 inches thick)
Bw2--24 to 36 inches; dark gray (10YR 4/1) fine sandy loam; black (10YR 2/1) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and nonplastic; few fine and common very fine roots; few very fine and common fine tubular pores; 5 percent pebbles; neutral; gradual smooth boundary. (10 to 24 inches thick)
Bw3--36 to 45 inches; dark grayish brown (10YR 4/2) fine sandy loam; very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and nonplastic; common very fine roots; common very fine and fine tubular pores; 5 percent pebbles; neutral; gradual smooth boundary. (6 to 12 inches thick)
Bw4--45 to 63 inches; yellowish brown (10YR 5/4) fine sandy loam; dark yellowish brown (10YR 3/4) moist; moderate coarse subangular blocky structure; hard, friable, slightly sticky and nonplastic; common very fine roots; common very fine and fine tubular pores; 5 percent pebbles; neutral.
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 8 miles northwest of Sanostee; 600 feet east and 950 feet south of the northwest corner of sec. 20, T.26N., R.20W.; Latitude 36 degrees 28 minutes 41 seconds N and Longitude 109 degrees 0 minutes 13 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically, the soil moisture control section is dry in some part more than 60 percent of the time that the soil is above 41 degrees F. at a depth of 20 inches. Typic ustic moisture regime.
Soil temperature - 44 to 47 degrees F.
Silicate clay content, control section weighted average - 8 to 18 percent
Depth to base of Mollic epipedon - 18 to 50 inches
Rock fragments - 0 to 5 percent
Organic matter - 1 to 4 percent in the epipedon
Reaction - slightly acid to neutral
A horizon
Hue: 7.5YR or 10YR
Value: 2 through 5 dry, 2 to 3 moist
Chroma: 1 through 3
BA and Bw horizons
Hue: 7.5YR or 10YR
Value: 2 through 5 dry, 2 through 4 moist
Chroma: 1 through 4
Texture: fine sandy loam or loam
BC and C horizons
Hue: 7.5YR or 10YR
Value: 4 through 7 dry, 3 through 6 moist
Chroma: 2 through 4
Texture: fine sandy loam or loam
Other features: some pedons contain loamy fine sand in the lower part of the particle-size control section
COMPETING SERIES: These are the Breece (CO), Breeton (MT), Chrishall (NM), Coberly (CO), Dotsero (CO), Hedoes (MT), Klizhin (NM), Parshall (ND), and Ruso (ND) series. Breece soils contain gravelly horizons with fragments of granite, and are moist during May and June. Breeton soils are moist during May and June. Coberly soils have bedrock at depths of 20 to 40 inches. Dotsero, Hedoes and Parshall soils are calcareous in the lower part of the solum and have secondary calcium carbonate accumulations. Klizhin soils are dry in some part of the moisture control section less than 60 percent of the time that the soil is above 41 degrees F. at a depth of 20 inches and mean annual soil temperature is 41 to 44 degrees F. Ruso soils have stratified sand and gravel within 40 inches.
GEOGRAPHIC SETTING: Tuntsa soils are on fan terraces, and on toeslopes and footslopes of stable landslides. Tuntsa soils formed in alluvium derived from Tertiary basalt and sandstone. Slopes are 1 to 15 percent. Elevations range from 7,600 to 8,600 feet. The mean annual precipitation is 18 to 20 inches. The mean annual air temperature is 42 to 45 degrees F. The frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kunz, Sandark, and Yahmore soils. Kunz soils have argillic horizons, are fine-loamy, and occur on adjacent backslopes. Sandark soils are sandy. Yahmore soils have argillic horizons and occur on older alluvial surfaces.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderately rapid permeability.
USE AND VEGETATION: Tuntsa soils are used for livestock grazing and marginal dryland farming. Present vegetation is blue grama, western wheatgrass, silvery lupine, bottlebrush squirreltail, and a few widely spaced Gamble oak and ponderosa pine. Crops grown in cultivated plots are potatoes and corn.
DISTRIBUTION AND EXTENT: Tuntsa soils are of small extent on the Defiance Uplift-Chuska Mountains portion of the Colorado Plateau province in northwest New Mexico and northeast Arizona. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Shiprock Area, San Juan County, New Mexico, 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to a depth of about 45 inches (A, BA, Bw1, Bw2, and Bw3 horizons)
Pachic subgroup - The presence of a mollic epipedon that is greater than 16 inches thick.
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.
The series type location was moved from the Fort Defiance Area, McKinley County New Mexico where it was originally proposed to the Shiprock Area, San Juan County New Mexico where it was established.