LOCATION GYPTUR NMEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Leptic Haplogypsids
TYPICAL PEDON: Gyptur very fine sandy loam--on an east facing toeslope of 1 percent at 5,190 feet elevation--rangeland. (Colors are for dry soil unless otherwise noted. When described, the pedon was dry throughout.)
A--0 to 2 inches; light yellowish brown (10YR 6/4) very fine sandy loam, yellowish brown (10YR 5/4) moist; strong very thick platy structure parting to moderate fine granular; soft, very friable, slightly sticky and nonplastic; few very fine vesicular pores; violently effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (2 to 4 inches thick)
2AB--2 to 5 inches; brown (10YR 5/3) silty clay loam, brown (10YR 4/3) moist; moderate thin platy structure parting to strong very fine granular; soft, very friable, sticky and plastic; few fine and very fine roots; few very fine vesicular pores; violently effervescent; moderately alkaline (pH 8.4); abrupt smooth boundary. (0 to 5 inches thick)
3By--5 to 17 inches; light brownish gray (2.5Y 6/2) gypsiferous loam, grayish brown (2.5Y 5/2) moist; moderate coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and common very fine roots; common very fine tubular pores; secondary silt-sized gypsum crystals segregated in common fine irregularly shaped filaments on faces of peds, few coarse sand-sized primary gypsum crystals; slightly effervescent; moderately alkaline (pH 7.9); clear smooth boundary. (9 to 16 inches thick)
3BCy--17 to 26 inches; light brownish gray (2.5Y 6/2) gypsiferous loam, grayish brown (2.5Y 5/2) moist; moderate coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine and common very fine roots; few very fine random tubular pores; secondary silt sized gypsum crystals segregated in few fine irregularly shaped filaments, few coarse sand-sized primary gypsum crystals throughout; slightly effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (8 to 14 inches thick)
3C--26 to 46 inches; light brownish gray (2.5Y 6/2) gypsiferous loam, grayish brown (2.5Y 5/2) moist; massive, platy rock structure; soft, very friable, slightly sticky and slightly plastic; few fine and very fine roots; few very fine irregularly shaped pores; 5 percent soft siltstone fragments; few coarse sand-sized primary gypsum crystals; slightly effervescent; moderately alkaline (pH 8.4); clear smooth boundary. (15 to 27 inches thick)
3Cr--46 inches; soft siltstone bedrock.
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 5.5 miles south of Shiprock; 2,350 feet south and 1,250 feet west of the northeast corner of section 24, T. 29 N., R. 18 W.; Latitude 36 degrees 42 minutes 47 seconds N and Longitude 108 degrees 41 minutes 11 seconds W.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically, the soil moisture control section is intermittently moist in some part from July to October and December to March. The winter moisture peak is not as high as the summer peak. Typic aridic moisture regime.
Soil temperature - 54 to 57 degrees F.
Soil depth - 40 to 60 inches or more to soft bedrock
Depth to gypsic horizon - 2 to 7 inches
Particle-size control section - clay content: 18 to 35 percent, by weighted average
Reaction - ranges from slightly alkaline in the surface to strongly alkaline in the underlying horizons.
Calcium carbonate equivalence - 5 to 15 percent
Hard rock fragments: 0 to 5 percent by volume, dominantly pebbles
A horizon
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4
Texture: very fine sandy loam or loam
Salinity, mmhos/cm: 2 to 4
Sodicity, SAR: 0 to 5
AB or Bw horizon
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4
Texture: clay loam, silty clay loam or loam
Salinity, mmhos/cm: 2 to 4
Sodicity, SAR: 5 to 13
Other features: horizon base is too shallow to qualify as a cambic horizon
By horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry, 4 or 5 moist
Chroma: 2 through 4
Texture: gypsiferous loam, gypsiferous silty clay loam, or gypsiferous silt loam
Salinity, mmhos/cm: 2 to 25
Sodicity, SAR: 5 to 30
Gypsum: 10 to 25 percent as both primary and secondary crystals
BCny and C horizons
Hue: 10YR or 2.5Y
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 4
Texture: gypsiferous loam, gypsiferous clay loam, or gypsiferous silt loam
Salinity, mmhos/cm: 8 to 25
Sodicity, SAR: 13 to 50
Gypsum content: 5 to 10 percent as mostly primary crystals
Other features: 5 to 30 percent soft siltstone or shale fragments; some pedons have texture of silty clay loam or silty clay
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Gyptur soils are on toeslopes of undulating plateaus and on dissected fan terraces. They formed in alluvium and residuum derived from thinly interbedded Cretaceous siltstone and shale. Slopes are 0 to 15 percent. Elevation ranges from 4,800 to 5,600 feet. The mean annual precipitation is 5 to 8 percent inches with 35 to 60 percent falling as rain from high intensity thunderstorms between July and October. 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 Fordbutte (T), Littlehat (T), Nataani (T), Persayo and Ravola soils. Fordbutte and Littlehat soils are moderately deep and lack gypsic horizons. Nataani soils are coarse-silty and moderately deep. Persayo soils are shallow. Ravola soils are stratified, lack diagnostic horizons, and are on floodplains.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately slow permeability.
USE AND VEGETATION: Gyptur soils are used for livestock grazing. Present vegetation is mat, mound and sickle saltbushes, Castle Valley clover, shadscale, alkali sacaton, Indian ricegrass, prickly pear cactus and halogeton.
DISTRIBUTION AND EXTENT: Gyptur soils are of small extent on the Four Corners Platform portion of the Colorado Plateau province in northwest New Mexico and possibly southwest Colorado. 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 surface to a depth of about 3 inches. (A horizon)
Gypsic horizon - The zone from 5 to about 17 inches. (3Bky horizon)
Paralithic contact - The presence of soft sedimentary bedrock at about 46 inches. (3Cr horizon)
Keys to Soil Taxonomy - Soils classified according to the Eighth Edition, 1998.
ADDITIONAL DATA: SAR values are bracketed around one pedon for which data is available. Salinity values were determined on five pedons, including the type location, with a Wheatstone bridge or an Instant EC kit. Calcium carbonate equivalence determined with a field volume calcimeter.