LOCATION MAPACHE NMTentative Series
The Mapache series consists of very deep, well drained soils that formed in slope alluvium and colluvium derived from latite and dacite. Mapache soils are on footslopes and backslopes of mountains. Slopes are 10 to 55 percent. Mean annual precipitation is about 27 inches and mean annual temperature is about 41 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Pachic Argiustolls
TYPICAL PEDON: Mapache loam--on a planar backslope of a mountain sloping 42 percent to the east-northeast at 9,240 feet elevation-forestland. (Colors are for dry soil unless otherwise noted. When described on August 25, 2000, the soil was slightly moist from 6 to 25 inches and otherwise dry.) Surface is covered with 5 percent boulders and 5 percent stones.
Oi--0 to 4 inches; slightly decomposed needles, twigs, and leaves; abrupt smooth boundary.
A1--4 to 9 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; single grain; loose, nonsticky and nonplastic; few coarse, few medium, common fine and common very fine roots; common fine and few very fine tubular pores; 5 percent stones and 5 percent boulders; slightly acid (pH 6.2); clear smooth boundary. (5 to 11 inches thick)
A2--9 to 15 inches; very dark grayish brown (10YR 3/2) gravelly loam, very dark brown (10YR 2/2) moist; weak very fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few medium, few fine, and few very fine roots; few fine and few very fine tubular pores; 10 percent gravel, 5 percent cobbles, and 3 percent stones; slightly acid (pH 6.5); clear smooth boundary. (6 to 14 inches thick)
A3--15 to 21 inches; brown (7.5YR 5/3) very gravelly sandy loam, dark brown (7.5YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few medium, few fine, and few very fine roots; few fine and few very fine tubular pores; few faint clay films on faces of peds; 25 percent gravel, 10 percent cobbles, and 5 percent stones; slightly acid (pH 6.2); gradual wavy boundary. (6 to 11 inches thick)
BE--21 to 28 inches; light brown (7.5YR 6/3) very gravelly sandy loam, brown (7.5YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few medium, few fine, and few very fine roots; few fine tubular pores; common distinct clay films on faces of peds; 40 percent gravel, 5 percent cobbles, and 5 percent stones; slightly acid (pH 6.1); gradual wavy boundary. (4 to 9 inches thick)
Bt1--28 to 35 inches; light brown (7.5YR 6/4) very gravelly sandy clay loam, brown (7.5YR 4/4) moist; weak medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few medium, few fine and few very fine roots; few fine tubular pores; common distinct clay films on faces of peds; 40 percent gravel, 5 percent cobbles, and 5 percent stones; slightly acid (pH 6.2); clear wavy boundary. (0 to 7 inches thick)
Bt2--35 to 62 inches; strong brown (7.5YR 5/6) extremely gravelly sandy clay loam, brown (7.5YR 4/4) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and few very fine roots; few very fine tubular pores; common distinct clay films on faces of peds; 40 percent gravel, 15 percent cobbles, 5 percent stones, and 5 percent boulders; slightly acid (pH 6.1).
TYPE LOCATION: Bandelier National Monument, Sandoval County, New Mexico; about 8 miles from west-southwest of Los Alamos; USGS Bland 7.5 minute topographic quadrangle; Latitude 35 degrees 51 minutes 02.31 seconds North and Longitude 106 degrees 26 minutes 02.27 seconds West, NAD 27.
RANGE IN CHARACTERISTICS: (Depths given are measured from the mineral soil surface)
Soil moisture- The soil moisture control section (SMCS) is moist in all parts from January to May and intermittently moist in some part from June to December. The SMCS is dry in all parts less than 40 percent of the time and dry in some or all parts more than 105 cumulative days when the soil temperature at 20 inches (50 cm) is above 41 degrees F. The soil moisture regime is typic ustic.
Average annual soil temperature: 42 to 45 degrees F.
Thickness of mollic epipedon: 16 to 29 inches
Depth to argillic horizon: 23 to 35 inches
Organic matter content: 2 to 4 percent in the mollic epipedon
Lithology of rock fragments: Dacite and latite
Particle-size control section (weighted averages):
Silicate clay content: 25 to 35 percent
Sand content: 40 to 65 percent
Fine sand or coarser content: 30 to 55 percent
Rock fragment content: 35 to 65 percent
A1 horizon
Value: 2 to 4 dry, 2 or 3 moist
Chroma: 1 or 2, dry or moist
Texture: loam or gravelly loam
Clay content: 10 to 20 percent
Base saturation: 75 to 95 percent
Rock fragments: total range is 5 to 30 percent
0 to 20 percent gravel
0 to 5 percent cobbles
2 to 5 percent stones
2 to 5 percent boulders
A2 horizon
Value: 2 to 4 dry, 2 or 3 moist
Chroma: 2 or 3 dry, 1 or 2 moist
Texture: cobbly loam or gravelly loam
Clay content: 12 to 22 percent
Reaction: slightly acid or neutral
Base saturation: 70 to 90 percent
Rock fragments: total range is 15 to 35 percent
10 to 20 percent gravel
5 to 10 percent cobbles
1 to 3 percent stones
0 to 3 percent boulders
A3 horizon
Value: 2 to 5 dry, 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: very gravelly sandy loam, very cobbly loam, very cobbly sandy loam
Clay content: 12 to 22 percent
Reaction: slightly acid or neutral
Base saturation: 70 to 90 percent
Rock fragments: total range is 35 to 60 percent
15 to 25 percent gravel
10 to 25 percent cobbles
2 to 5 percent stones
0 to 5 percent boulders
BE horizon
Value: 5 to 7 dry, 3 to 5 moist
Chroma: 2 or 3, dry or moist
Texture: very gravelly sandy loam, very cobbly loam, or very cobbly sandy loam
Clay content: 12 to 22 percent
Reaction: slightly acid to neutral
Base saturation: 65 to 85 percent
Rock fragments: total range is 35 to 55 percent
20 to 40 percent gravel
5 to 20 percent cobbles
5 to 10 percent stones
0 to 10 percent boulders
Bt horizons
Hue: 7.5YR or 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 2 to 6, dry or moist
Texture: gravelly sandy clay loam, very cobbly sandy clay loam, very cobbly loam, very gravelly sandy clay loam, extremely gravelly sandy clay loam, extremely cobbly clay loam, extremely gravelly clay loam
Clay content: 25 to 35 percent
Reaction: slightly acid or neutral
Base saturation: 60 to 85 percent
Rock fragments: total range is 25 to 80 percent
15 to 35 percent gravel
5 to 30 percent cobbles
0 to 10 percent stones
0 to 10 percent boulders
COMPETING SERIES: These are the Adellern, Braziel, Fessler, Pastorius, Pastorpeak, and Zillion. Adellern soils are derived from granite and have accumulations of secondary carbonates. Braziel and Fessler soils receive more moisture in May and June. In addition, Fessler soils have accumulations of secondary carbonates. astorius soils have sandy-skeletal substratum. Pastorpeak soils are derived from granite and sandstone, have accumulations of secondary carbonates, and are fragmental in the substratum. Zillion soils have accumulations of secondary carbonates.
GEOGRAPHIC SETTING: Mapache soils are on footslopes and backslopes of mountains. They formed in slope alluvium and colluvium derived from latite and dacite of the Tertiary age Tschicoma Formation. Slopes are 10 to 55 percent. Elevation ranges from 8,600 to 10,100 feet. The mean annual precipitation is 24 to 32 inches with about 45 percent falling as rain from high-intensity convective thunderstorms between July and September. The mean annual air temperature is 40 to 43 degrees F. The frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Estaban and Lucito soils. Estaban soils are fragmental, do not have a mollic epipedon, and occur on steep canyon backslopes. Lucito soils are clayey skeletal and occur on mountain footslopes and toeslopes.
DRAINAGE AND PERMEABILITY: Well drained; high or very high surface runoff; moderate permeability.
USE AND VEGETATION: Mapache soils are used for wildlife habitat and recreation. Present vegetation is Rocky Mountain Douglas fir, white fir, quaking aspen, Thurber's fescue, nodding brome, Parry's oatgrass, and western yarrow.
DISTRIBUTION AND EXTENT: Mapache soils are of small extent on the Jemez Volcanic Field part of the Southern Rocky Mountain province in northcentral New Mexico. The MLRA is 48A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Sandoval County, New Mexico; Bandelier National Monument Soil Survey; 2000. Mapache is a coined name.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon (Pachic feature)- The zone from 4 to 21 inches. (A1, A2, and A3 horizons)
Argillic horizon - The zone from 28 to greater than 62 inches. (Bt1, and Bt2 horizons)
Particle-size control section - The zone from 28 to 48 inches. (Bt1 and Bt2 horizons)
Classified according to Soil Taxonomy Second Edition, 1999.