LOCATION SUMMERFORD NMEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Ustic Haplargids
TYPICAL PEDON: Summerford gravelly sandy loam - rangeland (colors are for dry soil unless otherwise noted).
A--0 to 2 inches; dark gray (7.5YR 4/1) sandy loam, black (7.5YR 2.5/1) moist; weak medium platy structure; soft, very friable, nonsticky and nonplastic; few fine and very fine roots; slightly alkaline; clear wavy boundary (1 to 4 inches thick).
Bt1--2 to 6 inches; dark gray (7.5YR 4/1) gravelly sandy loam, black (7.5YR 2.5/1) moist; weak coarse subangular blocky structure; slightly hard and hard, very friable, nonsticky and nonplastic; few very fine roots; sand grains coated with oriented clay; 15 percent gravel; slightly alkaline; clear wavy boundary (2 to 5 inches thick).
Bt2--6 to 9 inches; dark gray (7.5YR 4/1) gravelly sandy loam, black (7.5YR 2.5/1) moist; weak coarse subangular blocky structure; slightly hard and hard, very friable, nonsticky and nonplastic; few fine roots; sand grains coated with oriented clay; 20 percent gravel; slightly alkaline; clear wavy boundary (2 to 4 inches thick).
Bt3--9 to 15 inches; brown (7.5YR 4/2) gravelly sandy loam, dark brown (7.5YR 3/2) moist; weak coarse subangular blocky structure; slightly hard and hard, very friable, nonsticky and nonplastic; few fine roots; sand grains coated with oriented clay; 20 percent gravel; slightly alkaline; clear wavy boundary (4 to 10 inches thick).
Bt4--15 to 23 inches; brown (7.5YR 5/2) gravelly loamy sand, dark brown (7.5YR 3/2) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few fine roots; sand grains coated with oriented clay; 25 percent gravel; slightly alkaline; clear wavy boundary (5 to 10 inches thick).
BCt--23 to 28 inches; brown (7.5YR 5/3) gravelly loamy sand, dark brown (7.5YR 3/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; sand grains coated with oriented clay; 20 percent gravel; slightly alkaline; clear wavy boundary (3 to 12 inches thick).
Ck1--28 to 35 inches; brown (7.5YR 5/3) gravelly sand, brown (7.5YR 4/3) moist; massive and single grain; soft and loose, very friable, nonsticky and nonplastic; few fine roots; 20 percent gravel; strongly effervescent; thin calcium carbonate coatings on gravel; moderately alkaline; abrupt smooth boundary (5 to 10 inches thick).
Ck2-- 35 to 42 inches; brown (7.5YR 5/3) gravelly sand, brown (7.5YR 4/3) moist; massive and single grain; soft and loose, very friable, nonsticky and nonplastic; 20 percent gravel; strongly effervescent; thin calcium carbonate coatings on gravel; moderately alkaline.
TYPE LOCATION: Dona Ana County, New Mexico; about 300 feet west of road; SW 1/4, NW 1/4 of section 1, T.21 S., R.1 E; 106 degrees 47 minutes 55 seconds west longitude and 32 degrees 31 minutes 10 seconds north latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: Intermittently moist in some part of the soil moisture control section during December through April and for more than 20 days cumulative during July through September. Driest during May and June. Ustic aridic soil moisture regime.
Clay content: averages less than 18 percent clay
Rock fragments: 15 to 35 percent
Organic matter: more than 1 percent in the surface
A horizon
Hue: 7.5YR, 10YR
Value: 3 through 5 dry, 2 through 4 moist
Chroma: 1 through 3, dry or moist
Texture: gravelly sandy loam, gravelly loamy sand
Bt horizon
Hue: 7.5YR, 10YR
Value: 3 through 5 dry, 2 through 4 moist
Chroma: 1 through 4, dry or moist
Ck horizon
Hue: 7.5YR, 10YR
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 2 through 4, dry or moist
Texture: gravelly sand, gravelly loamy sand
COMPETING SERIES: This is the Diaspar series. Diaspar soils have redder (2.5YR, 5YR) argillic horizons and do not have secondary calcium carbonate accumulations in the profile.
GEOGRAPHIC SETTING: Summerford soils are on alluvial fans and fan piedmonts. Slopes range from 5 to 15 percent. Elevations range from 4,400 to 5,500 feet. The mean annual precipitation ranges from 10 to 15 inches. The mean annual air temperature ranges from 57 to 63 degrees F. The frost-free period is about 170 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Onite, Algerita, Hawkeye, Hap, Berino, Yturbide and Dona Ana soils. Onite, Hap, Berino and Dona Ana soils have less organic carbon. Algerita and Yturbide soils do not have argillic horizons. Hawkeye soils are sandy.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately rapid permeability.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. Vegetation consists of black grama, Mormon tea, prickly pear, cholla, fluffgrass, snakeweed and a few soaptree yucca.
DISTRIBUTION AND EXTENT: Southern New Mexico. The series is of small extent. MLRA is 42.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Dona Ana County, New Mexico (Desert Project); 1997
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 2 inches (A horizon)
Argillic horizon - The zone from 2 to 28 inches (Bt1, Bt2, Bt3, Bt4, BCt horizons)
This series represents an identified soil within the Desert Soil-Geomorphology Project, Las Cruces, New Mexico. The project was a study of soils and geomorphology in an arid and semi-arid environment. The series is extensively referenced in many documents, publications and thesis. Revision outside the project area is discouraged in order to preserve the historical concept for research.
ADDITIONAL DATA: The classification is supported by analyses of four pedons in the vicinity of the type location. The analyses are in "The biochemistry of phosphorus cycling and phosphorus availability in a desert ecosystem", a Ph. D. thesis by Kate Lajtha for the Department of Botany, Duke University. These pedons were sampled arbitrary depths instead of by horizons and for this reason part of the Bt horizon was included in sampling the upper layer. When allowance is made for this, the analyses support an argillic horizon, and also show that these soils have too little organic carbon for a mollic epipedon. Thin section studies (L.H. Gile, unpublished information) show the coatings of oriented clay on sand grains that are typical of the argillic horizon in this area.
Updated competing series section 3/17/08, CEM.