LOCATION BERNAL NMEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic Aridic Lithic Argiustolls
TYPICAL PEDON: Bernal loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 3 inches; brown (10YR 4/3) loam, dark brown (10YR 3/3) moist, moderate very fine granular structure; soft, very friable; many very fine and fine roots; many fine pores; neutral; clear smooth boundary. (2 to 6 inches thick)
B1--3 to 7 inches; brown (7.5YR 4/3) sandy clay loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, neutral; clear smooth boundary. (2 to 6 inches thick)
B2t--7 to 12 inches; reddish brown (5YR 5/3) heavy sandy clay loam, reddish brown (5YR 4/3) moist; moderate medium prismatic structure parting to moderate fine angular and subangular blocky; hard, friable, slightly sticky; common thin clay coatings on sand grains as bridges between grains and as pore filling; neutral; abrupt smooth boundary. (4 to 8 inches thick)
R--12 to 22 inches; light colored, strongly cemented sandstone bedrock with few fractures and only slightly weathered on upper surface.
TYPE LOCATION: Torrance County, New Mexico; SW1/4 NE1/4 SW1/4 of section 15, T.9N., R.13E.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to bedrock range from 8 to 20 inches. Mean annual soil temperature ranges from 47 degrees to 59 degrees F. Rock fragments range from few to about 15 percent of which 60 percent is gravel. The solum is neutral or mildly alkaline. The control section ranges from heavy sandy loam to sandy clay loam and averages 18 to 35 percent clay. Carbonates are usually absent throughout the profile but range to a trace in the immediate area of the lithic contact.
The A horizon has hue of 10YR through 5YR, value of 3 through 5 dry, 2 or 3 moist, and chroma of 2 or 3. It is clay loam, loam, fine sandy loam or loamy sand.
The B2t horizon has hue usually of 7.5YR or 5YR and ranging to 10YR, value of 4 through 6 dry, 3 through 5 moist, and chroma of 2 through 4. It is clay loam, loam, sandy loam, or fine sandy loam.
COMPETING SERIES: These are the Apache, Cabezon, Encierro, Hagerman, Montvale, Progresso, and Salas series. Apache soils lack argillic horizons and have Cca horizons above the lithic contact. Cabezon soils have fine-textured cobbly control sections with the clay fraction dominated by montmorillonite. Encierro soils have fine-textured control sections and have an accumulation of calcium carbonate above the lithic contact. Hagerman, Progresso, and Salas soils have bedrock at depths of 20 to 40 inches; also, Hagerman and Progresso soils lack a mollic epipedon. Montvale soils have numerous flagstones throughout the soil and have an accumulation of calcium carbonate above the lithic contact.
GEOGRAPHIC SETTING: The Bernal soils are on mesa tops and upland ridge crests on bedrock controlled landscape. Slopes range from 0 to 30 percent. Elevations are 5,300 to 7,900 feet. The soils formed in moderately fine textured noncalcareous sandy material weathered from the sandstone, with possible minor addition of eolian material. The climate is semiarid continental. At the type location, the mean annual temperature is about 46 degrees to 52 degrees F. The average annual precipitation is about 12 to 16 inches. The precipitation pattern is characterized by a marked summer maximum resulting from thunderstorms. The frost-free season is 120 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carnero, Pastura and Travessilla soils and the competing Encierro and Hagerman soils. Carnero soils have sandstone at depths of 20 to 40 inches. Pastura soils lack a mollic epipedon and have a petrocalcic horizon at depths of less than 20 inches. Travessilla soils lack a mollic epipedon and an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Rangeland. Principal native plants are blue grama, sand dropseed, and galleta, and commonly with an overstory of pinyon and juniper.
DISTRIBUTION AND EXTENT: Central and northern New Mexico and central Colorado. The series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Santa Fe County, New Mexico, 1970.