LOCATION AMCEC NMEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Vitrandic Haplustalfs
TYPICAL PEDON: Amcec extremely gravelly loam--in rangeland on a north facing slope of 16 percent at an elevation of 8,600 feet (Colors are for dry soils unless otherwise noted.)
A--0 to 4 inches; dark reddish brown (5YR 3/4) extremely gravelly loam, dark reddish brown (2.5YR 2.5/4) moist; moderate fine granular structure; soft, friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine irregular pores; 80 percent gravel, 5 percent cobbles, 3 percent stones, (rock fragments are mostly cinders with some basalt); neutral (pH 6.8); clear smooth boundary. (4 to 10 inches thick)
Bt--4 to 16 inches; dark reddish brown (2.5YR 3/4) very gravelly loam, dark reddish brown (2.5YR 2.5/4) moist, slightly hard, firm, sticky and plastic; many very fine and fine roots; common fine irregular pores; many distinct clay films coating faces of peds; 40 percent gravel and 5 percent cobbles, (rock fragments are mostly cinders with some basalt); slightly alkaline (pH 7.4); clear wavy boundary. (6 to 18 inches thick)
Btk1--16 to 39 inches; dark reddish brown (5YR 3/4) extremely gravelly coarse sandy loam, dark reddish brown (2.5YR 2.5/4) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; common distinct clay films bridging sand grains; calcium carbonate occurs as many fine segregated coats on rock fragments; 85 percent gravel and 5 percent cobbles, (rock fragments are mostly cinders with some basalt); violently effervescent (6 percent calcium carbonate equivalent); slightly alkaline (pH 7.8); gradual wavy boundary.
Btk2--39 to 53 inches; dark reddish brown (2.5YR 3/4) extremely gravelly loamy coarse sand, dark reddish brown (2.5YR 2.5/4) moist; massive; loose, loose, nonsticky and nonplastic; few very fine and fine roots; common distinct clay films bridging sand grains; calcium carbonate occurs as common fine segregated coats on rock fragments; 80 percent gravel, 5 percent cobbles, 5 percent stones (rock fragments are mostly cinders with some basalt); strongly effervescent; slightly alkaline (pH 7.8); gradual irregular boundary. (The combined thickness of the Btk horizons is 23 to 44 inches.)
Bk--53 to 70 inches; dark reddish brown (2.5YR 3/4) extremely gravelly loamy coarse sand, dark reddish brown (2.5YR 2.5/4) moist; massive; loose, loose, nonsticky and nonplastic; few very fine and fine roots; 50 percent gravel (cinders), 20 percent cobbles (cinders), and 20 percent stones (basalt); calcium carbonate occurs a few fine segregated coats on rock fragments; strongly effervescent; slightly alkaline (pH 7.8). (0 to 25 inches thick)
TYPE LOCATION: McKinley County, New Mexico; Marquez Quadrangle; about 3.3 miles northwest of Marquez, New Mexico; 107 degrees 20 minutes 41 seconds west longitude, 35 degrees 20 minutes 55 seconds north latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: The SMCS is usually moist, in some part, for more than 90 cumulative days from May to October. It is usually dry, in all parts, for less than 90 cumulative days during the same period. It is continuously moist in some part November to April. The period of maximum precipitation is July to October. The soil is driest during May and June. Typic ustic moisture regime.
Soil Temperature: 42 to 47 degrees F
Particle size control section: 20 to 30 percent clay, greater than 35 percent sand, and greater than 35 percent gravel and cobble sized cinders.
Depth to secondary calcium carbonate: 15 to 25 inches with less than 10 percent calcium carbonate equivalent.
A horizon:
Hue: 2.5YR to 10YR
Value: 3 or 4 dry, 2.5 or 3 moist
Chroma: 2 to 4 dry or moist
Rock fragments: 60 to 90 percent total range (mostly cinders with some basalt)
20 to 80 percent gravel
5 to 30 percent cobbles
0 to 10 percent stones
0 to 1 percent boulders
Reaction: slightly acid or neutral
Note--Where mollic colors occur the horizon is too thin to make a mollic epipedon.
Bt horizon:
Hue: 2.5YR or 5YR
Value: 3 or 4 dry, 2.5 or 3 moist
Chroma: 3 or 4 dry or moist
Texture: loam, clay loam, or sandy clay loam
Rock fragments: 60 to 90 percent total range (mostly cinders with some basalt)
20 to 60 percent total range
15 to 60 percent gravel
5 to 20 percent cobbles
Reaction: neutral or slightly alkaline
Btk horizon:
Hue: 2.5YR or 5YR
Value: 3 or 4 dry, 2.5 or 3 moist
Chroma: 3 or 4 dry or moist
Texture: coarse sandy loam, loamy coarse sand, or sandy clay loam
Rock fragments: 50 to 90 percent total range (mostly cinders with some basalt)
40 to 85 percent gravel
5 to 10 percent cobbles
0 to 5 percent stones
Bk horizon (when present):
Hue: 2.5YR or 5YR
Value: 3 or 4 dry, 2.5 or 3 moist
Chroma: 4 or 6 dry or moist
Texture: loamy coarse sand or sandy loam
Rock fragments: 80 to 95 percent total range (mostly gravel and cobble sized cinders with basalt stones)
40 to 90 percent gravel
0 to 20 percent cobbles
0 to 20 percent stones
COMPETING SERIES: There are no competitors.
GEOGRAPHIC SETTING: The Amcec soils formed in eolian material and slope alluvium over residuum derived from cinders and are on cinder cones (Mt. Taylor and Mesa Chivato volcanic fields). Slopes are 10 to 50 percent. Elevations range from 7,600 to 9,200 feet. The mean annual temperature is 40 to 45 degrees F., and the mean annual precipitation is 16 to 20 inches. The frost free period is 90 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Canoneros, Montillo, and Tsoodzil soils on lava plateaus and cinder cones. These soils have mollic epipedons and have greater than 35 percent clay in the particle size control section.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained, high runoff, and moderate permeability.
USE AND VEGETATION: This series is used for rangeland and wildlife habitat. The present vegetation is Arizona fescue, mountain muhly, prairie junegrass, blue grama, bottlebrush squirreltail, and Gambel oak.
DISTRIBUTION AND EXTENT: West central, New Mexico. MLRA 39. LRR-D. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: McKinley County Area, New Mexico; McKinley County and Parts of Cibola and San Juan Counties, 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon: The zone from 0 to 4 inches. (A horizon)
Argillic horizon: The zone from 4 to 53 inches. (Bt, Btk1, and Btk2 horizons)
Vitrandic feature: Greater than 35 percent (by volume) cinders (>2.0 mm) in all horizons from the surface to 75 cm.
Classified according to Soil Taxonomy Second Edition, 1999.
ADDITIONAL DATA: NSSL S92NM031-001.