LOCATION LITTLEHAT NM COEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, semiactive, mesic Sodic Haplocambids
TYPICAL PEDON: Littlehat silt loam -- on a northwest facing footslope of 4 percent at 5,260 feet elevation -- rangeland. (Colors are for dry soil unless otherwise noted. When described, the pedon was dry throughout.)
Ay--0 to 2 inches; light yellowish brown (2.5Y 6/4) silt loam, light olive brown (2.5Y 5/4) moist; strong very thick platy structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; many very fine vesicular pores; secondary fine sand sized gypsum crystals segregated in few fine irregularly shaped filaments and seams; violently effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (2 to 4 inches thick)
By--2 to 10 inches; light yellowish brown (2.5Y 6/4) silt loam, light olive brown (2.5Y 5/4) moist; moderate coarse prismatic structure parting to weak coarse subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; common very fine vesicular pores; secondary fine sand-sized gypsum crystals segregated in few fine irregularly shaped filaments; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (4 to 9 inches thick)
C1--10 to 23 inches; grayish brown (2.5Y 5/2) silt loam, dark grayish brown (2.5Y 4/2) moist; weak fine subangular blocky structure; soft, very friable, sticky and slightly plastic; few fine and common very fine roots; 5 percent soft siltstone fragments; few lenses of coarse sand-sized primary gypsum crystals; strongly effervescent; strongly alkaline (pH 8.5); clear smooth boundary. (6 to 13 inches thick)
C2--23 to 31 inches; light brownish gray (2.5Y 6/2) parachannery silt loam, grayish brown (2.5Y 5/2) moist; massive, platy rock structure; soft, very friable, sticky and slightly plastic; few fine and common very fine roots; 15 percent parachanners; few lenses of coarse sand-sized primary gypsum crystals; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (8 to 14 inches thick)
Cr--31 inches; siltstone bedrock.
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 9.5 miles south of Shiprock and .25 mile south of Sulphur Spring; 2,200 feet south and 1,000 feet east of the northwest corner of sec. 24, T.28N., R.18W; Latitude 36 degrees 38 minutes 55 seconds N and Longitude 108 degrees 42 minutes 57 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry, typically, the soil moisture control section is intermittently moist in some part from July to October and December to March. Typic aridic moisture regime.
Soil temperature - 54 to 57 degrees F.
Soil depth - 20 to 40 inches to soft bedrock.
Silicate clay content, control section weighted average - 18 to 35.
Reaction - moderately to strongly alkaline.
Calcium carbonate equivalent - 10 to 20 percent.
Hard rock fragments - 0 to 10 percent by volume, dominantly small sandstone channers.
Ay horizon - Hue: 10YR or 2.5Y.
Chroma: 3 or 4.
Salinity, mmhos/cm: 4 to 16.
Sodicity, SAR: 13 to 30.
Gypsum content: 1 to 10 percent as secondary crystals.
Other features: this horizon lacks sufficient thickness to qualify as a gypsic horizon.
By and C horizons - Hue: 10YR or 2.5Y.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 2 through 4.
Texture: loam, silt loam, or silty clay loam.
Salinity, mmhos/cm: 8 to greater than 16.
Sodicity, SAR: 30 to 100.
Gypsum content: 1 to 5 percent as mostly primary crystals.
Other features: 0 to 35 percent soft, parachanners; some pedons have thin horizons of very fine sandy loam.
COMPETING SERIES: There are no competitors.
GEOGRAPHIC SETTING: Littlehat soils are on summits, footslopes, and backslopes of undulating plateaus. Littlehat soils formed in alluvium and residuum derived from Cretaceous siltstone and shale. Slopes are 1 to 45 percent. Elevation ranges from 5,000 to 5,600 feet. The mean annual precipitation is 5 to 8 inches with 35 to 60 percent falling as rain from high-intensity thunderstorms between July and September. The mean annual temperature is 51 to 54 degrees F. The average frost-free period is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gyptur, Nataani, Persayo, Ravola, and Tsebitai soils. Gyptur soils are deep, have gypsic horizons, and occur on adjacent summits. Nataani soils are coarse-silty, have gypsic horizons, and occur on toeslopes below Littlehat soils. Persayo soils are shallow to bedrock. Ravola soils are very deep, stratified, and occur on flood plains and alluvial fans. Tsebitai soils are very deep, coarse-silty, and occur on fan terraces.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff, moderate permeability.
USE AND VEGETATION: Littlehat soils are used for livestock grazing. Present vegetation is a sparse stand of mat saltbush, Indian ricegrass, alkali sacaton, and Castle Valley clover.
DISTRIBUTION AND EXTENT: Littlehat soils are of moderate extent on the Four Corners Platform portion of the Colorado Plateau province in northwest New Mexico and possibly southwest Colorado. MLRA 35.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Shiprock Area, Parts of San Juan County, New Mexico and Apache County, Arizona; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to a depth of about 2 inches. (Ay horizon)
Depth to Cambic horizon - 2 to 10 inches.
Sodic feature - SAR exceeds 13 in By horizons within the zone from 2 to about 10 inches.
Paralithic contact - The presence of soft sedimentary bedrock at about 31 inches.
ADDITIONAL DATA: The series type location was sampled for full characterization by the National Soil Survey Laboratory (NSSL) as pedon S86NM-045-005. Salinity values were also determined on six pedons, including the type location, with a Wheatstone bridge. Calcium carbonate equivalence also determined with a field volume calcimeter. Soil and Range Inventory Report of District 12; U.S.D.I., BIA, Shiprock Agency, 1978. Soil profile #4611-1 is within the range of this series.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003