LOCATION HAP NM+AZEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Calciargids
TYPICAL PEDON: Hap gravelly loam, native rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 3 inches; brown (7.5YR 5/4) gravelly loam, brown (7.5YR 4/4) moist; weak medium platy and weak medium granular structure; soft, very friable, nonsticky; many very fine roots and pores; noncalcareous; approximately 15 percent gravel; neutral; clear irregular boundary (2 to 12 inches thick)
Bt1--3 to 7 inches; reddish brown (5YR 4/4) gravelly sandy clay loam, dark reddish brown (2.5YR 3/4) moist; weak coarse subangular blocky structure; slightly hard, friable, sticky; many very fine roots and pores; few faint clay films; noncalcareous; about 15 percent gravel; neutral; clear irregular boundary. (0 to 4 inches thick)
Bt2--7 to 18 inches; red (2.5YR 4/6) gravelly sandy clay loam, dark red (2.5YR 3/6) moist; moderate coarse subangular blocky structure; very hard, friable, very sticky; common very fine roots; many very fine interstitial and tubular pores; many distinct thick clay films; noncalcareous; about 15 percent gravel; neutral; clear irregular boundary. (10 to 16 inches thick)
Btk3--18 to 28 inches; reddish brown (5YR 5/4) gravelly sandy clay loam, reddish brown (5YR 4/4) moist; moderate coarse subangular blocky structure; very hard, friable, sticky; few very fine roots; many very fine interstitial and tubular pores; common faint clay films; strongly calcareous with some segregated lime as thin mycelia; about 20 percent gravel; slightly alkaline; abrupt irregular boundary. (8 to 18 inches thick)
Bk1--28 to 38 inches; white (5YR 8/1) weakly cemented caliche of gravelly sandy clay loam, pinkish gray (5YR 6/2) moist; friable in part when moist; massive; common very fine tubular pores; strongly calcareous; moderately alkaline; clear irregular boundary. (5 to 18 inches thick)
Bk2--38 to 50 inches; pinkish gray (7.5YR 7/2) sandy clay loam, light reddish brown (5YR 6/3) moist; massive; soft, very friable, slightly sticky; many fine and very fine tubular pores; strongly calcareous, lime is disseminated; 10 percent fine gravel; moderately alkaline. (0 to 15 inches thick)
TYPE LOCATION: Hidalgo County, New Mexico; 200 feet east of NE corner section 26, T.22S., R.17W.
RANGE IN CHARACTERISTICS:
Soil moisture - Intermittently moist in some part of the soil moisture control section during December-April and for more than 20 days cumulative during July-September. Driest during May and June. Typic aridic soil moisture regime.
Rock fragments ranges from - 15 to 35 percent.
A horizon and upper part of B horizon are leached of carbonates.
A horizon
Hue: 5YR to 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 3 to 5
Structure: moderate fine and medium platy or granular structure or single grained.
Bt horizon
Hue: 2.5YR or 5YR
Value: 3 to 5 dry, 3 or 4 moist
Chroma: 4 to 6.
Texture: gravelly loam, gravelly sandy loam or gravelly sandy clay loam with most of the sand fraction being coarse.
Texture: weak, moderate medium or coarse subangular blocky structure.
Other features: illuvial clay is evident as bridges between sand grains, coatings in pores, on sand grains, and rock fragments.
Bk horizon
Hue: 5YR or 7.5YR
Value: 6 to 8 dry, 5 to 7 moist
Chroma: 1 to 3.
Texture: gravelly sandy clay loam, gravelly loam or gravelly clay loam
Cementation: soft to weakly cemented.
Calcium carbonates equivalents: contains 15 to 50 percent
COMPETING SERIES: These are
Brenda (NM),
Blackmagic (CA),
Cornville (AZ),
Dona Ana (NM),
Elizario (NM),
Jagerson (AZ),
Kidwell (NV),
Madurez (NM),
McNew (NM),
Mohave (AZ),
Nutt (NM),
Poachie (AZ), and
Tres Hermanos (NM) series.
Brenda soils have gravelly sand or fine sand in the lower part of the profile below the argillic horizon.
Blackmagic, Dona Ana and McNew soils have calcic horizon and carbonates that range from 2 to 10 inches. Blackmagic soils do not have 2.5YR hue argillic horizon
Cornville, Elizario, Poachie, Madurez, and Mohave soils contain less than 15 percent rock fragment in the PSCS.
Jagerson soils particle size control section is noneffervescent and contains less than 5 percent calcium carbonates.
Kidwell soils moist in the control section for less than 20 days in the summer.
Mohave soil contain 27 to 40 percent clay in the PSCS.
Tres Hermanos soils are calcareous in all parts of the Bt horizon.
GEOGRAPHIC SETTING: The Hap soils are on moderately sloping to gently rolling old alluvial fans from granitic hills and mountains. The soils formed in gravelly medium to moderately coarse textured alluvium. The climate is semiarid continental with a mean annual temperature of about 60 degrees F. The average annual precipitation is about 10 inches and comes mainly during the summer. The Thornthwaite P-E Index is about 14.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Luzena, Sonoita, and Yturbide soils and the competing Mohave and Tres Hermanos soils. Luzena soils have bedrock at depths of less than 20 inches and have fine textured control sections. Sonoita soils have coarse-loamy control section. Yturbide soils are sandy and lack B horizons.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Used mainly as rangeland. Principal vegetation is bush muhly, threeawn, sideoats grama, black grama, mesquite bush, tea weed, cacti, sotol, and yucca.
DISTRIBUTION AND EXTENT: Southern New Mexico, where it is of moderate extent. MLRAs 41 & 42.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Hidalgo County, New Mexico, 1973.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 0 to 3 inches (A horizon)
Argillic horizon - the zone from 3 to 28 inches (Bt1, Bt2 and Btk3 horizon)
Calcic horizon - the zone from 28 to 50 inches (Bk1 and Bk2 horizon)