LOCATION TWICK NMEstablished Series
TAXONOMIC CLASS: Clayey, mixed, superactive, mesic, shallow Ustic Haplargids
TYPICAL PEDON: Twick cobbly silty clay loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A--0 to 1 inch; brown (7.5YR 4/2) cobbly silty clay loam, dark brown (7.5YR 3/2) moist; weak fine granular structure; hard, firm, sticky and plastic; few fine roots; few fine pores; 25 percent cobbles; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.); abrupt smooth boundary. (1 to 3 inches thick)
Bt1--1 to 4 inches; brown (7.5YR 5/2) clay loam, brown (7.5YR 4/2) moist; weak medium and fine subangular blocky structure; hard, firm, sticky and plastic; few fine and medium roots; few fine and medium pores; thin patchy clay films; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.0); clear smooth boundary. (2 to 4 inches thick)
B2t--4 to 17 inches; brown (7.5YR 5/2) clay, brown (7.5YR 4/4) moist; moderate medium and fine subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine and medium roots; few very fine pores; thin continuous clay films; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.2); clear smooth boundary. (7 to 13 inches thick)
Cr--17 inches; soft calcareous shale with a few beds of sandstone.
TYPE LOCATION: San Juan County, New Mexico; 5.7 miles north of the junction of county road 18 and New Mexico Highway 544, on New Mexico 544 then 1.1 miles NW on road to section T.32N., R.8W.
RANGE IN CHARACTERISTICS:
Soil moisture: Ustic aridic moisture regime
Solum thickness and depth to a paralithic contact: 10 to 20 inches
Coarse fragments: 5 to 35 percent
Reaction: slightly alkaline or moderately alkaline
Organic carbon: more than 0.6 percent
A horizon
Hue: 7.5YR or 10YR
Value: 4, 5 or 6 dry, 3, 4 or 5 moist
Chroma: 2 through 4
Texture: cobbly clay loam or cobbly silty clay loam
Bt horizons
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 4
Texture: clay loam, clay, or silty clay loam
Clay content: averages more than 35 percent clay
COMPETING SERIES: There are no competing series.+
GEOGRAPHIC SETTING: Twick soils are on upland hills and breaks. Slope gradient ranges from 5 to 25 percent. They formed in alluvium and fine textured residuum from shale. Elevation ranges from about 6,400 to 7,200 feet. The mean annual precipitation ranges from 10 to 13 inches. The average annual temperature is about 48 to 52 degrees F. and the frost free season is about 120 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buckle, Penistaja, and Travessilla soils. Penistaja and Buckle soils lack bedrock within depth of 20 inches and are fine, loamy. Travessilla soils have a lithic contact, are loamy and lack an argillic horizon.
DRAINAGE AND PERMEABILITY: Rangeland.
USE AND VEGETATION: Present vegetation is pinyon pine, oneseed juniper, antelope bitterbrush, serviceberry, sideoats grama, and mountain mahogany.
DISTRIBUTION AND EXTENT: Uplands in northwestern New Mexico, possibly extending into Colorado. Series is of small extent. MLRAs 35 & 36.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: San Juan County, Eastern Part, New Mexico, 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from 0 to 1 inches (A horizon)
Argillic horizon - The zone from 1 to 17 inches (Bt horizons)
Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Tenth Edition, 2006.