LOCATION DULA NM+CO
Established Series
Rev. JPP-TWH-KLS
01/2018
DULA SERIES
The Dula series consists of very deep, poorly drained soils that formed in alluvium. Dula soils are on flood plains and have slopes of 0 to 2 percent. The mean annual temperature is about 6.1 degrees C. and the mean annual precipitation is about 508 mm.
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Cumulic Endoaquolls
TYPICAL PEDON: Dula loam - Pasture and hayland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 10 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; strong medium granular structure; slightly hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; common fine interstitial pores; neutral (pH 7.0); abrupt smooth boundary.
A2--10 to 30 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate coarse granular structure; slightly hard, friable, moderately sticky and moderately plastic; many fine and common very fine roots; common fine tubular pores; few fine faint yellowish brown (10YR 5/4) masses of iron concentrations; neutral (pH 7.0); clear smooth boundary. (combined thickness of A1, A2 - 21 to 40 cm)
Bg1--30 to 46 cm; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; few fine tubular pores; few fine distinct yellowish brown (10YR 5/8) masses of iron concentrations; neutral (pH 7.0); clear smooth boundary.
Bg2--46 to 71 cm; grayish brown (2.5Y 5/2) loam, very dark grayish brown (2.5Y 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few fine roots; few fine tubular pores; many medium distinct reddish yellow (7.5YR 6/8) masses of iron concentrations; neutral (pH 7.0); clear smooth boundary. (combined thickness of Bg1, Bg2 - 36 to 102 cm)
2C--71 to 152 cm; variegated colors, extremely gravelly coarse sand; single grain; loose, nonsticky and nonplastic; few fine roots; 60 percent gravel and 10 percent cobbles; neutral (pH 7.0).
TYPE LOCATION: Rio Arriba County, New Mexico; within the Village limits of Chama; New Mexico state plane coordinates 653,475 meters north and 123,121 meters east; Lat. 36 degrees, 53 minutes, 15 seconds N.; Long. 106 degrees, 34 minutes, 58 seconds W.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 4.4 to 7.2 degrees C.
Thickness of mollic epipedon: 61 to 89 cm
Depth to 2C horizon: 61 to 102 cm
Depth to seasonal endosaturation and aquic conditions: 30 to 51 cm
Particle-size control section:
Upper part:
Clay content: 18 to 25 percent
Sand content: 30 to 50 percent
Lower part:
Clay content: 1 to 10 percent
Rock fragment content: 50 to 85 percent
A horizon
Value: 4 or 5 dry, 2 or 3 moist
Clay content: 18 to 25 percent
Reaction (pH): 6.6 to 7.3
Bg horizon
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 1 to 3 dry or moist
Clay content: 18 to 25 percent
Reaction (pH): 6.6 to 7.3
2C horizon
Texture: extremely gravelly coarse sand, extremely gravelly sand
Clay content: 1 to 10 percent
Rock fragment content: 50 to 85 percent--40 to 60 percent gravel, 10 to 25 percent cobbles
Reaction (pH): 6.6 to 7.3
COMPETING SERIES:
Degarmo (OR) - lack redox concentrations in the mollic epipedon
Flintcreek soils (MT) - have endosaturation above 30 cm
GEOGRAPHIC SETTING:
Landform - flood plains
Elevation - 1,950 to 2,440 meters
Slopes - 0 to 2 percent
Parent material - alluvium
Mean annual air temperature - 4.4 to 7.2 degrees C.
Mean annual precipitation - 406 to 584 mm
Frost-free period - 80 to 100 days
Dula soils have a water table at 30 to 107 cm April through August and are subject to frequent flooding.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Poorly drained; very low runoff. Moderate permeability in the upper part and very rapid in the lower part.
USE AND VEGETATION: Dula soils are used for irrigated pasture and hayland and wildlife habitat. The present vegetation is narrowleaf cottonwood, shrubby cinquefoil, tufted hairgrass, bluegrass, and sedges.
DISTRIBUTION AND EXTENT: Northern New Mexico, southern Colorado. LRR D, MLRA 36. The series is of small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Rio Arriba County, New Mexico, 1989. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 71 cm (A1, A2, Bg1, Bg2 horizons)
Endosaturation and aquic conditions: 30 to 152 cm (Bg1, Bg2, and 2C horizons)
Lithologic discontinuity: extremely gravelly coarse sand at 71 cm (2C horizon)
Irregular decrease in organic matter: 0 to 71 cm (A1, A2, Bg1, Bg2 horizons), inferred from landscape position
Dula soils have a frigid temperature regime and are in an aquic soil moisture regime with a typic subclass.
National Cooperative Soil Survey
U.S.A.