LOCATION GOTHARD AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Ustic Natrargids
TYPICAL PEDON: Gothard fine sandy loam - rangeland. (Colors are for dry soil unless otherwise noted.)
An1--0 to 2 inches; light brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak medium and thin platy structure; slightly hard, very friable, nonsticky and nonplastic; common fine and medium roots; common fine discontinuous and few fine and medium continuous tubular pores; slightly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (0 to 2 inches thick)
An2--2 to 5 inches; gray (10YR 6/1) fine sandy loam, dark grayish brown (10YR 4/2) moist; massive; hard, friable, nonsticky and nonplastic; common fine and medium roots; many fine discontinuous and few fine continuous tubular pores; strongly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (2 to 5 inches thick)
Btnz--5 to 11 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; moderate fine and medium prismatic parting to moderate fine and medium angular and subangular blocky structure; hard, firm, sticky and plastic; common fine and medium roots; many exped interstitial and common fine and very fine tubular pores; common faint clay films on peds and in pores; slightly effervescent; strongly alkaline (pH 9.0); clear smooth boundary. (6 to 10 inches thick)
Btknz1--11 to 24 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; strongly fine subangular blocky structure; slightly hard, friable, sticky and plastic; many fine and medium roots in upper 6 inches and common in lower 7 inches; many fine exped and common fine and medium tubular pores; few faint clay films on peds; strongly and violently effervescent; many fine light gray (10YR 7/2) soft calcium carbonate masses, light brownish gray (10YR 6/2) moist; very strongly alkaline (pH 9.6); abrupt wavy boundary. (6 to 14 inches thick)
Btknz2--24 to 42 inches; pink (7.5YR 7/4) clay loam, brown (7.5YR 5/4) moist; common medium faint coatings of reddish yellow (7.5YR 6/6) on peds; weak coarse prismatic parting to moderate medium and subangular blocky structure; very hard, firm, sticky and plastic; common fine exped roots; many fine exped and common fine and very fine tubular pores; faint continuous clay films on peds and lining pores; slightly effervescent in matrix and violently effervescent in masses; many medium to large white (N 8/) soft calcium carbonate masses, reddish yellow (7.5YR 6/6) and pinkish gray (7.5YR 7/2) moist; very strongly alkaline (pH 9.6); abrupt wavy boundary. (6 to 8 inches thick)
2Bknz--42 to 51 inches; light gray (2.5Y 7/2) sandy loam, grayish brown (2.5Y 5/2) moist; few fine distinct black (N 2/) mottles; moist; massive; extremely hard, firm, sticky and plastic; common fine and very fine tubular pores; slightly effervescent in matrix and violently effervescent in common fine and medium distinct white (N 8/) lime segregations; very strongly alkaline (pH 9.4); abrupt wavy boundary. (5 to 11 inches thick)
2Cnz--51 to 80 inches; similar colors to 2Bknz plus a few fine and medium distinct coatings of light olive brown (2.5Y 5/6), stratified loamy sand and sandy loam with thin lenses of sandy clay loam; massive; weakly cemented, very hard, friable, nonsticky and nonplastic; common fine and few medium tubular pores; slightly effervescent in spots; strongly alkaline (pH 9.0).
TYPE LOCATION: Cochise County, Arizona; 16 1/2 miles south and 2 3/4 miles east of Willcox, Arizona, reached by Kansas Settlement Road; 1/4 mile west and 100 feet north of the SE corner of sec. 27, T.16S., R.25E.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during July-September and December-February and for less than 90 days cumulative in some part of the epipedon. Driest during May and June. Ustic aridic soil moisture regime.
Soil temperature: 59 degrees to 68 degrees F.
A horizons
Hue: 10YR, 7.5YR
Value: 4 through 8 dry, 4 or 5 moist
Chroma: 2 through 4, dry or moist
Texture: sandy loam, fine sandy loam, loam or silt loam
Reaction: moderately to very strongly alkaline
Bt horizons
Hue: 5YR through 10YR, dominantly 7.5YR or 10YR
Value: 3 through 8 dry, 3 through 5 moist
Chroma: 2 through 6, dry or moist
Texture: sandy clay loam, clay loam or loam
Reaction: strongly to very strongly alkaline
Bk and C horizons
Texture: Textures range from clay to loamy sand. It is highly stratified, and the strata vary in thickness.
Reaction: strongly alkaline to very strongly alkaline
Small amounts of amorphous or crystalline gypsum occur in the substratum in some pedons.
COMPETING SERIES: These are the Crot (AZ) and Sikes (NM) series. Crot soils are somewhat poorly drained. Sikes soils have a watertable and are somewhat poorly drained. Sikes would classify as an Epiaquolls or an Endoaquolls.
GEOGRAPHIC SETTING: Gothard soils are on level to nearly level alkali flats and bordering playas at elevations of 3,600 to 4,300 feet. Slopes range from 0 to 5 percent. These soils formed in old lake and fan deposited alluvium from mixed sources, including rhyolite, andesite, quartzite, granite and limestone. The climate is warm semiarid continental. The mean annual air temperature ranges from 58 degrees to 66 degrees F. and the mean annual precipitation typically ranges from 10 to 16 inches. Precipitation occurs as thunderstorms from July through September and as gentle fall and winter rains. The frost-free period is 155 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chorro, Crot, Doubleadobe, Cogswell, Elfrida, Karro, and Stewart series.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow runoff; slow to very slow permeability.
USE AND VEGETATION: Gothard soils are used for livestock grazing and as limited irrigated cropland. Irrigated areas are primarily planted to alfalfa and permanent pasture. Native vegetation is alkali sacaton, alkali lovegrass, inland saltgrass, tobosa, blue grama and vine mesquite with scattered four-wing saltbush, ephedra and seepweed.
DISTRIBUTION AND EXTENT: Southeastern Arizona and southwestern New Mexico portion of the Chihuahuan desert. MLRA is 41. Gothard soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Sulphur Springs Valley Area, Arizona, 1942.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 5 inches (An1 and An2 horizons)
Natric horizon: The zone from 5 to 11 inches (Btnz horizon)
Proposal to reclassify from a Typic subgroup to an Ustic subgroup April 2000.
Soil Taxonomy Second Edition, 1999