LOCATION MARA NMEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Typic Haplustepts
TYPICAL PEDON: Mara loam-pine grassland. (Colors are for dry soils unless otherwise noted.)
A--0 to 2 inches; dark grayish brown (2.5Y 4/2) loam, very dark grayish brown (2.5Y 3/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and plastic; many very fine and fine roots; many common fine interstitial pores; strongly effervescent; mildly alkaline (pH 7.6); abrupt smooth boundary. (l t 5 inches thick)
Bw1--2 to l0 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; moderate fine and medium subangular blocky structure; hard, friable, sticky and plastic; common fine and very fine roots; common very fine tubular pores; strongly effervescent; mildly alkaline (pH 7.6); clear smooth boundary. (6 to l3 inches thick)
Bw2--10 to 18 inches; brown (l0YR 5/3) silty clay loam, dark brown (l0YR 4/3) moist; weak medium subangular blocky structure; hard, firm, sticky and plastic; common very fine and fine roots; common very fine and fine tubular pores; strongly effervescent; mildly alkaline (pH 7.8); gradual smooth boundary. (3 to 8 inches thick)
Bk1--18 to 30 inches; pale brown (l0YR 6/3) clay loam, brown (l0YR 4/3) moist; massive; hard, firm, sticky and plastic; few very fine and fine roots; few very fine tubular pores; 10 percent pebbles; strongly effervescent with few medium masses of calcium carbonate; mildly alkaline (pH 7.8); gradual smooth boundary. (3 to 30 inches thick)
Bk2--30 to 60 inches; pale brown (l0YR 6/3) clay loam, brown (l0YR 5/3) moist; massive; hard, firm, sticky and plastic; few very fine roots; few fine tubular pores; 10 percent soft shale fragments; strongly effervescent with few medium soft masses of calcium carbonate; mildly alkaline (pH 7.8).
TYPE LOCATION: Rio Arriba County, New Mexico; about 6 miles west and 2.5 miles south of Chama on the Lee Wood Ranch; New Mexico state plane coordinates 2,126,040 feet north and 368,850 feet east; 106 degrees, 41 minutes, 54 seconds west longitude; 36 degrees, 55 minutes, 07 seconds north latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: Moist in some parts of the SMCS December through March and July through September. The driest months are May and June.
Soil Temperature: 42 to 47 degrees F.
Calcium carbonate equivalent: Less than l5 percent.
A horizon: Hue l0YR or 2.5Y Value: 2 through 5 dry; 2 through 4 moist Chroma: 2 through 4
B horizon: Hue l0YR or 2.5Y Value: 3 through 6 dry; 4 or 5 moist Chroma: 2 through 4 Texture: Clay loam or silty clay loam Percent Clay: 27 to 35 percent weighted average
COMPETING SERIES: These are the Broadus(T)(MT), Doney (MT), Eaglewing(T)(MT), and Macar(MT). All these soils are moist in some parts of the soil moisture control during the spring and early summer. In addition, Doney soils have a paralithic contact at 20 to 40 inches and Eaglewing soils have calcic horizons.
GEOGRAPHIC SETTING: Mara soils are on hills and knolls. Slopes range from 2 to l2 percent. Elevations are 7,400 to 8,200 feet. The soil formed in alluvium from shale and sandstone. Mean annual precipitation is l6 to l8 inches in the form of winter snow and heavy thundershowers during July and August. May and June are the driest months. Mean annual temperature is 42 to 44 degrees F., and the frost-free period is 80 to l00 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Wiggler, Rombo, and Hogg soils. Wiggler is shallow to shale. Rombo soils are fine textured and moderately deep to shale. Hogg soils are fine textured and have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderately slow permeability.
USE AND VEGETATION: Mara soils are used mainly for livestock grazing. The natural vegetation is Western wheatgrass, Columbia needlegrass, Arizona fescue, fringed sage, and Gambels oak, with widely scattered Ponderosa pine and Rocky Mountain juniper.
DISTRIBUTION AND EXTENT: North central New Mexico. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Arriba County, New Mexico, l989.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 2 inches. (A horizon) When the colors meet the requirements of a mollic epipedon, the horizon is less than 7 inches thick.
Cambic horizon: The zone from 2 to l8 inches (Bw horizons)