LOCATION AROJOMIL NMTentative Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ustalfic Petrocalcids
TYPICAL PEDON: Arojomil silt loam-sloping 2 percent to the south-southwest (200 degrees) at 6,650 feet elevation-rangeland. (Colors are for dry soil unless otherwise noted. When described on May 24, 2002, the soil was dry throughout.)
A--0 to 2 inches; yellowish brown (10YR 5/4) loam, dark brown (10YR 3/3) moist; moderate medium platy structure parting to moderate very fine granular; soft, very friable, slightly sticky and slightly plastic; common fine and common very fine roots; common very fine irregularly shaped pores; non to slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (1 to 5 inches thick)
Bt--2 to 10 inches; dark yellowish brown (10YR 4/4) clay loam, dark brown (10YR 3/3) moist; moderate coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; few fine and common very fine roots; common fine and few very fine tubular pores; clay films as common faint and few distinct coats in pores and on ped faces; non to slightly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 10 inches thick)
Btk--10 to 15 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 4/4) moist; moderate fine subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine and few very fine roots; few fine and few very fine tubular pores; 12 percent gravel as petronodes; clay films as common distinct and few faint coats in pores and on ped faces; strongly to violently effervescent, secondary calcium carbonate segregated as common fine rounded and discontinuous concretions (7 percent calcium carbonate equivalent); moderately alkaline (pH 8.3); clear smooth boundary. (5 to 20 inches thick)
Bk1--15 to 22 inches; very pale brown (10YR 7/3) very gravelly loam, light yellowish brown (10YR 6/4) moist; weak fine subangular blocky structure; very hard, firm, slightly sticky and slightly plastic; common very fine roots; few very fine tubular pores; 40 percent gravel as petronodes; violently effervescent, secondary calcium carbonate segregated as common medium rounded concretions and many coarse irregular shaped coats on ped faces (17 percent calcium carbonate equivalent); moderately alkaline (pH 8.4); gradual wavy boundary. (7 to 16 inches thick)
Bk2--22 to 33 inches; very pale brown (10YR 8/2) very gravelly loam, light yellowish brown (10YR 6/4) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine roots; few very fine tubular pores; 45 percent gravel as petronodes; violently effervescent, secondary calcium carbonate segregated as many coarse rounded concretions and many irregular shaped coats on ped faces (33 percent calcium carbonate equivalent); moderately alkaline (pH 8.4); abrupt wavy boundary. (7 to 12 inches thick)
Bkkm1--33 to 41 inches; white (10YR 8/1) petrocalcic material, very strongly cemented but penetrable; common very fine roots (49 percent calcium carbonate equivalent); moderately alkaline (pH 8.4); clear wavy boundary. (4 to 10 inches thick)
Bkkm2--41 to 46 inches; white (10YR 8/1) petrocalcic material, very rigid and indurated; moderately alkaline (pH 8.4). (5 to 20+ inches thick)
TYPE LOCATION: Santa Fe County, New Mexico; about 5.5 miles northeast of Stanley; 1,622 feet north and 100 feet east of the southwest corner of section 6, T.11N., R.10E.; USGS Stanley 7.5 minute topographic quadrangle; Latitude 35 degrees 12 minutes 0 seconds North and Longitude 105 degrees 55 minutes 13 seconds West NAD 27.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is intermittently moist in some part from July to October and December to March. It is assumed to be dry in all parts for less than 75 percent of the time (cumulative), when the soil temperature at 20 inches is 41 degrees F. or higher. The soils are driest in May and June. The soil moisture regime is ustic aridic.
Soil temperature - 51 to 54 degrees F.
Thickness of ochric epipedon - 2 to 5 inches
Depth to base of argillic horizon - 12 to 18 inches
Depth to calcic horizon - 10 to 34 inches
Depth to petrocalcic horizon - 20 to 40 inches
Salinity, mmhos/cm: 0 to 2
Sodicity, SAR: 0 to 4
Particle-size control section weighted averages -
Silicate clay content: 18 to 27 percent;
Sand content: 25 to 40 percent;
Fine sand or coarser content: 15 to 25 percent;
Rock fragment content: total range is: 0 to 35 percent gravel, lithology of fragments is mostly petronodes with a few of granite, gneiss, and schist.
A horizon
Hue: 7.5 YR or 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 to 4, dry or moist
Clay content: 10 to 20 percent
Calcium carbonate equivalent: 0 to 1 percent
Rock fragment content: total range is 0 to 10 percent, mostly gravel
Bt horizon
Hue: 7.5 YR or 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: loam, silt loam, silty clay loam, or clay loam
Clay content: 18 to 27 percent
Calcium carbonate equivalent: 5 to 10 percent
Rock fragment content: total range is 0 to 10 percent, mostly gravel
Salinity, mmhos/cm: 0 to 1
Sodicity, SAR: 0 to 4
Btk horizon
Hue: 7.5 YR or 10YR
Value: 4 to 6 dry, 4 or 5 moist
Chroma: 3 or 4 moist
Texture: loam, silt loam, very gravelly loam, gravelly silt loam
Clay content: 18 to 27 percent
Calcium carbonate equivalent: 10 to 15 percent
Rock fragment content: total range is 10 to 35 percent, mostly gravel
Salinity, mmhos/cm: 0 to 2
Sodicity, SAR: 0 to 4
Bk horizons
Hue: 7.5 YR or 10YR
Value: 6 or 7 dry, 5 or 6 moist
Chroma: 3 or 4, dry or moist
Texture: very gravelly loam, very gravelly sandy loam, extremely cobbly loam, extremely cobbly sandy loam, extremely gravelly sandy loam
Clay content: 8 to 18 percent
Calcium carbonate equivalent: 15 to 45 percent
Rock fragment content: total range is 35 to 70 percent
5 to 40 percent gravel
5 to 30 percent cobbles
Salinity, mmhos/cm: 0 to 2
Sodicity, SAR: 0 to 4
Bkkm horizons
Hue: 10YR
Value 8, dry or moist
Chroma 1, dry or moist
Calcium carbonate equivalent: 40 to 70 percent
COMPETING SERIES: This is the Lapoint series. Soils from this series are cooler, and receive less annual moisture at a steady year round rate with a slight increase at the end of the growing season.
GEOGRAPHIC SETTING: Arojomil soils are on interfluves of undulating plains formed in eolian material derived from sandstone and siltstone over alluvium derived from Precambrian age granite, gneiss, and schist. Slopes are 1 to 5 percent. Elevation ranges from 6,100 to 7,200 feet. The mean annual precipitation is 12 to 14 inches with about 45 percent falling as rain from high-intensity convective thunderstorms between July and September. The mean annual air temperature is 49 to 51 degrees F. The frost-free period is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Pastura and Tapia soils. Pastura soils are loamy, are shallow to a petrocalcic horizon, and occur on shoulders. Tapia soils are very deep, do not have a petrocalcic horizon, and occur on summit positions adjacent to the Arojomil soils.
DRAINAGE AND PERMEABILITY: Well drained; low surface runoff; permeability is moderately slow.
USE AND VEGETATION: Arojomil soils are used for livestock grazing, urban development, and some wildlife habitat. Present vegetation is blue grama, threeawn, whipple cholla, tree cholla, broom snakeweed, and fringed sagewort.
DISTRIBUTION AND EXTENT: Arojomil soils are of moderate extent in the Estancia Basin of North-Central New Mexico. The MLRA is 70C.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES PROPOSED: Santa Fe County, New Mexico; Santa Fe Area Soil Survey Update; 2003. Arojomil is a coined name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - soil surface to a depth of about 2 inches. (A horizons)
Argillic Horizon - 2 to 15 inches. (Bt and Btk horizons)
Calcic horizon - 15 to 33 inches. (Bk1 and Bk2 horizons).
Petrocalcic Horizon 33 to 46 inches. (Bkkm horizons)
Classified according to Keys to Soil Taxonomy Tenth Edition, 2006.
ADDITIONAL DATA: The series type location has been sampled for full characterization by the Soil Survey Laboratory (SSL), Lincoln, NE, as soil survey sample number S-NM-02-049-009; Calcium carbonate equivalence was determined using a field calcimeter.