LOCATION LLANO NM
Established Series
Rev GWC-DAW
01/2015
LLANO SERIES
The Llano series consists of very deep, somewhat poorly drained soils that formed in gypsiferous lacustrine deposits. These nearly level soils are on relict lake beds. Slopes range from 0 to 3 percent. The mean annual precipitation is about 10 inches and the mean annual air temperature is about 67 degrees F.
TAXONOMIC CLASS: Coarse-gypseous, hypergypsic, thermic, shallow Petrogypsic Haplosalids
TYPICAL PEDON: Llano gypsiferous loamy sand - rangeland. (Colors are for dry soil unless otherwise noted)
Ayyz--0 to 2 inches (0 to 5 cm); white (2.5Y 8/1) gypsiferous loamy sand, pale yellow (2.5Y 8/2), moist; 4 percent clay; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; many fine platy gypsum crystals throughout; noneffervescent, 78 percent gypsum; moderately alkaline, pH 7.9; electrical conductivity 37.6 dS/m (mmhos/cm); strongly saline; abrupt wavy boundary.
Byyz--2 to 13 inches (5 to 32 cm); white (2.5Y 8/1) gypsiferous loamy fine sand, pale yellow (2.5Y 8/2), moist; 4 percent clay; moderate thick platy structure; hard, very firm, nonsticky, nonplastic; many very fine irregular gypsum crystals throughout; noneffervescent, 87 percent gypsum; moderately alkaline, pH 8.1; electrical conductivity 53.4 dS/m (mmhos/cm); strongly saline; abrupt wavy boundary.
Byyzm1--13 to 36 inches (32 to 90 cm); pale yellow (2.5Y 8/2), pale yellow (2.5Y 7/3), moist; massive; many very fine irregular gypsum crystals throughout; noneffervescent, 83 percent gypsum; slightly alkaline, pH 7.8; electrical conductivity 82.3 dS/m (mmhos/cm); strongly saline; gradual smooth boundary.
Byyzm2--36 to 52 inches (90 to 132 cm); white (10YR 8/1), light gray (10YR 7/1), moist; massive; few coarse tubular pores; 2 percent fine masses of oxidized iron on surfaces along pores; many very fine irregular gypsum crystals throughout; noneffervescent, 86 percent gypsum; moderately alkaline, pH 8.0; electrical conductivity 89.6 dS/m (mmhos/cm); strongly saline; abrupt wavy boundary.
2Cyyz--52 to 60 inches (132 to 152 cm); light gray (5Y 7/1) gypsiferous fine sandy loam, gray (5Y 6/1), moist; 8 percent clay; massive; slightly hard, very firm, nonsticky, nonplastic; many very fine irregular gypsum crystals throughout; noneffervescent, 89 percent gypsum; moderately alkaline, pH 8.0; electrical conductivity 113.9 dS/m (mmhos/cm); strongly saline; gradual wavy boundary.
TYPE LOCATION: Dona Ana County, New Mexico. USGS Quad Heart of the Sands NW; approximately 5.3 miles east and 1.0 miles north of the junction of Range Roads 7 and 10; 1,868 feet south and 2,702 feet east of the northwest corner of Section 26, Township 16 S, Range 5 E. Latitude: 32 degrees 53 minutes 38.2 seconds north Longitude: 106 degrees 24 minutes 7.7 seconds west, NAD 83; UTM Easting: 368857 meters UTM Northing: 3640401 meters. UTM zone 13.
RANGE IN CHARACTERISTICS:
Soil moisture: Typic aridic soil moisture regime based on precipitation. The moisture control section is usually dry in all parts more than three-fourths of the time that the soil temperature exceeds 41 degrees F. at 20 inches.
Mean annual soil temperature: 66 to 72 degrees F.
Particle-size control section (weighted average)
Clay content: 2 to 10 percent
Reaction: slightly or moderately alkaline
Salinity: moderately to strongly saline
Percent gypsum: 60 to 90 percent
Ayyz horizons
Hue: Gley 1, 10YR, 2.5Y, 5Y
Value: 1 to 9 dry, 2 to 8 moist
Chroma: N to 4, dry or moist
Texture: gypsiferous sand, gypsiferous loamy sand, gypsiferous loamy fine sand, gypsiferous sandy loam
Clay: 0 to 10 percent
Gypsum: 60 to 90 percent
Salinity: moderately saline to strongly saline
Byyz horizon
Hue: Gley 1, 10YR, 2.5Y, 5Y
Value: 1 to 9 dry, 2 to 8 moist
Chroma: N to 4, dry or moist
Texture: gypsiferous sand, gypsiferous loamy sand, gypsiferous loamy fine sand, gypsiferous sandy loam, gypsiferous silt loam, gypsiferous loam
Clay: 2 to 10 percent
Gypsum: 60 to 90 percent
Reaction: slightly alkaline to moderately alkaline
Byyzm horizons
Cemented: gypsum
Hardness: very strongly to indurated
Thickness: 20 to 50 inches, continuous
2Cyyz horizon
Hue: Gley 1, 10YR, 2.5Y, 5Y
Value: 4 to 7 dry, 3 to 6 moist
Chroma: 1 to 4, dry or moist
Texture: gypsiferous sand, gypsiferous loamy sand, gypsiferous loamy fine sand, gypsiferous sandy loam, gypsiferous fine sandy loam, gypsiferous silt loam, gypsiferous loam
Clay: 6 to 15 percent
Gypsum: 60 to 90 percent
Reaction: slightly alkaline to moderately alkaline
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Llano soils are on relict lakebeds on basin floors. Slope is 0 to 3 percent. These soils formed from gypsiferous lacustrine deposits. Elevation ranges from 3,890 to 3,990 feet. The mean annual precipitation is 8 to 12 inches. Precipitation falls mostly during the months of July through September. The mean annual air temperature is 64 to 70 degrees F. The frost-free period is 180 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the tentative Ratscat (NM), Mamtrack (NM) and Salago (NM) soils. Ratscat soils lack a petrogypsic horizon. Mamtrack soils lack a salic horizon, Salago soils have a water table at 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; low to medium runoff; very slow permeability.
USE AND VEGETATION: The major uses are military exercises and wildlife habitat. Native vegetation is iodine bush.
DISTRIBUTION AND EXTENT: South central New Mexico, limited to the Alkali Flat of the Tularosa Basin. MLRA 42, Llano is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: White Sands Missile Range, Dona Ana County, New Mexico, 2014. The name Llano is derived from Spanish and defines as flat.
REMARKS: Diagnostic horizon and features recognized in this pedon are:
Particle-size control section - the zone from 0 to 13 inches (Ayyz and Byyz horizons)
Ochric epipedon- the zone from 0 to 2 inches (Ayyz horizon)
Gypsic horizon- the zone from 2 to 12.5 inches (Byyz horizon)
Petrogypsic horizon-the zone from 12.5 to 52 inches (Byyzm horizons)
Salic horizon- the zone from 0 to 60 inches (Ayyz, Byyz, Byyzm and 2Cyyz horizons)
Episaturation- the zone from 0 to 20 inches.
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy, Twelfth Edition, 2014.
Revised for the correlation of White Sands Missile Range, New Mexico; October, 2014, NMS
National Cooperative Soil Survey
U.S.A.