LOCATION MILLPAW NMEstablished Series
The Millpaw series consists of very deep, well drained, slowly permeable soils that formed in fine textured alluvium on fans and valley sides. Slopes are 0 to 7 percent. The mean annual precipitation is about l4 inches, and the mean annual temperature is about 50 degrees F.
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Pachic Argiustolls
TYPICAL PEDON: Millpaw loam--rangeland. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; brown (10YR 4/3) loam, dark brown (10YR 3/3) moist; weak medium platy structure; slightly hard, very friable, slightly sticky and nonplastic; many fine and very fine roots; slightly alkaline; abrupt smooth boundary. (2 to 6 inches thick)
Bt1--4 to l0 inches; brown (10YR 4/3) clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; common fine tubular pores; common thin clay films on faces of peds and lining pores; slightly alkaline; clear smooth boundary. (5 to l9 inches thick)
Bt2--l0 to 35 inches; brown (10YR 4/3) clay, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; hard, firm, very sticky and very plastic; common fine roots; common moderately thick clay films on faces of peds; slightly alkaline; abrupt smooth boundary. (9 to 30 inches thick)
Bk--35 to 60 inches; brown (7.5YR 5/4) sandy clay loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; strongly effervescent; few fine lime accumulations; moderately alkaline.
TYPE LOCATION: Catron County, New Mexico; about 12 miles west of Quemado in NE l/4, Sec. 10 T. l N. R. 18W.; 108 degrees, 42 minutes, 26 seconds w. longitude; 34 degrees, 19 minutes, 52 seconds n. latitude.
RANGE IN CHARACTERISTICS:
Soil Moisture: The SMCS is usually moist, in all parts for less than 90 cumulative days from April through October. It is usually dry, in some part, for more than 120 cumulative days during the same period. Intermittently moist in some part November through March, but not moist in all parts for 45 consecutive days from January through April. The period of maximum precipitation is July through October. The soil is driest during May and June. Aridic ustic moisture regime.
Soil temperature: 49 to 56 degrees F.
Mollic epipedon: 20 to 40 inches thick
Reaction: slightly to moderately alkaline
Particle size control section- average 35 to 60 percent clay.
A horizon:
Hue: 10YR or 7.5YR
Value: 4 or 5 dry, 2 to 4 moist
Chroma: 2 or 3
Bt horizon:
Hue: l0YR or 7.5YR
Value: 3 to 6 dry, 2 to 4 moist
Chroma: 2 to 4
Texture: clay loam, clay or sandy clay
Clay content: 35 to 60 percent.
Btk and Bk horizon:
Hue: 10YR, 7.5YR or 5YR
Value: 4 to 7 dry, 3 to 5 moist
Chroma: 3 to 6
Texture: sandy clay loam, loam, clay loam
Clay content: 20 to 35 percent
Calcium carbonate equivalent: less than 15 percent
COMPETING SERIES: Current competitors are the Conchovar (NM), Irwin (KS), Knifehill (NM), Lubbock (KS), Nutreeah (NM), Ruidoso (NM) and Tully (KS) series. Conchovar soils have a water table within 40 inches. Knifehill soils contain more than 35 percent clay throughout the series control section. Nutreeah has accumulations of soluble salts and SARs of 1 to 5. Ruidoso soils receive most of the precipitation in the summer. Also, the Irwin, Lubbock, and Tully soils are in LRR-H and are more moist in May and June.
GEOGRAPHIC SETTING: Millpaw soils are on fans and valley sides. Slopes range from 0 to 7 percent. Elevation ranges from 6700 to 7,800 feet. The mean annual precipitation is about l2 to 16 inches, and mean annual temperature is about 45 to 53 degrees F. The frost-free period is about l00 to l35 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amenson, Datil, Albinas and Ralphston soils. Amenson has a petrocalcic horizon within 20 inches. Datil, Albinas and Ralphston soils have less than 35 percent clay in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.
USE AND VEGETATION: This soil is used for rangeland. Present vegetation includes blue grama, rabbitbrush, bottlebrush squirreltail, broom snakeweed, scattered pinyon and juniper.
DISTRIBUTION AND EXTENT: West central New Mexico. MLRA 35, LRR-D. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Catron County, New Mexico, 1982.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon: 0 to 35 inches
Argillic horizon: 4 to 35 inches
Classified according to Soil Taxonomy Second Edition, 1999.