LOCATION FORDBUTTE NMEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Typic Haplocambids
TYPICAL PEDON: Fordbutte very fine sandy loam -- on an east facing simple slope of 2 percent at 5,440 feet elevation -- rangeland. (Colors are for dry soil unless otherwise noted. When described the soil was moist between 2 and 20 inches and dry below.)
A--0 to 4 inches; light yellowish brown (10YR 6/4) very fine sandy loam, brown (10YR 4/3) moist; moderate thick platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; few fine and very fine roots; few very fine vesicular pores; strongly effervescent; moderately alkaline (pH 7.9); clear smooth boundary. (2 to 4 inches thick)
Bw--4 to 14 inches; light yellowish brown (10YR 6/4) loam, yellowish brown (10YR 5/4) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few medium and common fine and very fine roots; common very fine irregularly shaped pores; strongly effervescent; strongly alkaline (pH 8.7); clear wavy boundary. (9 to 12 inches thick)
2Bk--14 to 20 inches; light yellowish brown (2.5Y 6/4) loam, light olive brown (2.5Y 5/4) moist; moderate coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few medium and common fine and very fine roots; common very fine continuous tubular pores; 2 percent fine gravel; strongly effervescent, secondary calcium carbonates segregated in few fine irregularly shaped filaments and on underside of rock fragments; strongly alkaline (pH 8.6); clear smooth boundary. (4 to 7 inches thick)
3BCk--20 to 26 inches; light yellowish brown (2.5Y 6/4) loam, light olive brown (2.5Y 5/4) moist; weak coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few medium and fine and common very fine roots; common very fine tubular pores; 5 percent soft siltstone fragments; strongly effervescent, secondary calcium carbonates segregated in common fine irregularly shaped filaments and on underside of soft rock fragments; strongly alkaline (pH 8.7); clear smooth boundary. (0 to 7 inches thick)
4Cy--26 to 34 inches; light yellowish brown (2.5Y 6/4) gypsiferous loam, light olive brown (2.5Y 5/4) moist; massive, platy rock structure; hard, firm, slightly sticky and slightly plastic; few medium and very fine roots; few very fine horizontal tubular pores; 50 percent soft siltstone fragments; secondary fine sand-sized gypsum crystals segregated in common fine irregularly shaped filaments and on undersides of soft rock fragments; slightly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (5 to 10 inches thick)
4Cr--34 inches; thinly interbedded siltstone and very fine-grained soft sandstone bedrock.
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 8 miles north of Little Water; 2,500 feet west and 500 feet north of the southeast corner of sec. 23, T.27N., R.18W; Latitude 36 degrees 33 minutes 15 seconds N and Longitude 108 degrees 43 minutes 40 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.
Silicate clay content, control section weighted average - 18 to 30 percent.
Reaction - moderately to strongly alkaline.
Hard rock fragments - 0 to 5 percent.
Soil depth - 20 to 40 inches to soft bedrock.
A horizon-
Value: 4 or 5 moist.
Chroma: 4 or 5.
Salinity, mmhos/cm: 2 to 4.
Bw horizon-
Value: 4 or 5 moist.
Chroma: 4 or 5.
Texture: loam, silt loam, or silty clay loam.
Salinity, mmhos/cm: 2 to 4.
Sodicity, SAR: 5 to 30.
Bk and BCk horizons-
Hue: 10YR or 2.5Y.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 through 4.
Texture: loam, silt loam, or silty clay loam.
Calcium carbonate equivalent: 15 to 20 percent.
Salinity, mmhos/cm: 2 to 4.
Sodicity, SAR: 5 to 30.
Other features: 0 to 5 percent soft siltstone fragments.
Cy horizon-
Value: 5 through 7.
Chroma: 2 through 4.
Texture: gypsiferous loam, silt loam, or silty clay loam.
Calcium carbonate equivalent: 15 to 20 percent.
Salinity, mmhos/cm: 4 to 8.
Sodicity, SAR: 5 to 13.
Gypsum content: 1 to 3 percent.
Other features: 5 to 65 percent soft siltstone fragments.
COMPETING SERIES: This is the Sagers series. Sagers soils are very deep.
GEOGRAPHIC SETTING: Fordbutte soils are on toeslopes below cuestas and knolls of undulating plateaus. Fordbutte soils formed in alluvium, thin eolian deposits, and residuum derived from Cretaceous siltstone, sandstone, and shale. Slopes are 1 to 3 percent. Elevation ranges from 5,300 to 6,300 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 Hamburn, Littlehat, Persayo, Ravola, and Tsebitai soils. Ravola and Hamburn soils are very deep, stratified, and occur on flood plains. Littlehat soils lack cambic horizons and are strongly saline-sodic. Persayo soils are shallow to soft bedrock on adjacent footslopes. Tsebitai soils are coarse-silty and very deep.
DRAINAGE AND PERMEABILITY: Well drained, slow runoff, moderate permeability.
USE AND VEGETATION: Fordbutte soils are used for livestock grazing. Present vegetation is alkali sacaton, Indian ricegrass, galleta, shadscale, sickle saltbush, and scarlet globemallow.
DISTRIBUTION AND EXTENT: Fordbutte soils are of moderate extent on the western San Juan Basin and Four Corners Platform portions of the Colorado Plateau province in northwest New Mexico. LRR-D; 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 to a depth of about 4 inches (A horizon).
Cambic horizon - The zone from about 4 to 14 inches (Bw horizon).
Paralithic contact - The presence of soft sedimentary bedrock at about 34 inches.
Great group rationale - The Bk and BCk horizons do not qualify as calcic horizons because there is not a 5 percent decrease by weight, of calcium carbonate equivalent in the C horizons and the underlying paralithic contacts (Cr layers).
Classified according to Soil Taxonomy Second Edition, 1999.
ADDITIONAL DATA: The series type location was sampled for full characterization by the National Soil Survey Laboratory (NSSL) as pedon S86NM-045-011.
Salinity values were also determined on three pedons, including the type location, with a Wheatstone bridge.