LOCATION NAWT IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Ultic Palexerolls
TYPICAL PEDON: Nawt extremely stony loam--on an east-facing slope of 50 percent under native rangeland vegetation at 4,950 feet elevation. (Colors are for dry soil unless otherwise stated.) When described on August 20, l977, the soil profile was slightly moist in the A horizon and dry below.
A--0 to 5 inches; brown (l0YR 5/3) extremely stony loam, dark brown (l0YR 3/3) moist; moderate fine platy structure parting to weak fine granular; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; many very fine tubular pores; 30 percent stones, 5 percent cobbles and 30 percent gravel; neutral (pH 7.2); abrupt smooth boundary. (3 to ll inches thick)
Bt1--5 to l0 inches; brown (l0YR 5/3) gravelly clay, dark brown (l0YR 3/3) moist; moderate fine or medium subangular blocky structure; hard, firm, very sticky and very plastic; many fine and very fine roots; many very fine tubular pores; many moderately thick clay films on faces of peds and in pores; l5 percent gravel; neutral (pH 7.2); clear smooth boundary. (5 to 9 inches thick)
Bt2--l0 to l8 inches; brown (7.5YR 5/4) gravelly clay, dark brown (7.5YR 4/4) moist; strong medium subangular blocky structure parting to weak medium prismatic; very hard, firm, very sticky and very plastic; common fine or very fine roots; common very fine tubular pores; many moderately thick clay films on faces of peds and in pores; 5 percent cobbles, 20 percent gravel; neutral (pH 7.2); clear smooth boundary. (9 to l4 inches thick)
Bt3--18 to 36 inches; light yellowish brown (10YR 6/4) stony clay, brown (7.5YR 5/4) moist; moderate medium subangular blocky structure; very hard, very firm, sticky and plastic; common fine and very fine roots; common very fine tubular pores; common thin clay films on faces of peds and in pores; 5 percent stones, 5 percent cobbles, and 10 percent gravel; mildly alkaline (pH 7.4); clear smooth boundary. (8 to 18 inches thick)
Bk--36 to 45 inches; very pale brown (10YR 7/4) very gravelly clay loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few very fine roots; few very fine tubular pores; 10 percent cobbles and 45 percent gravel; strongly effervescent in veins; lime segregated in common rounded fine filaments; moderately alkaline (pH 8.4); clear smooth boundary. (10 to 20 inches thick)
Cr--45 to 62 inches; brown (7.5YR 4/2) decomposing lime coated vesicular welded tuff, dark reddish brown (5YR 3/3) moist.
TYPE LOCATION: Twin Falls County, Idaho; about 8 miles east of Hollister, Idaho; in the northwest 1/4, northeast 1/4, southwest 1/4, section 24, T. 12 S., R. 17 E.
RANGE IN CHARACTERISTICS
Average annual soil temperature - 48 to 52 degrees F.
Mollic epipedon thickness - 10 to 18 inches
Depth to base of argillic horizon - 30 to 40 inches
Clay content of control section - 40 to 50 percent
Rock fragments in control section - 10 to 30 percent
Depth to bedrock - 40 to 60 inches
Base saturation in upper 30 inches - 65 to 75 percent
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Bt horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - GR-SIC, GR-C, OR ST-C
Bk horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - GR-L, GR-SIL, OR GRV-CL
Calcium carbonate equivalent - 5 to 15 percent
COMPETING SERIES: This is the Driscoll series. Driscoll soils are slightly to medium acid, have E horizons above the argillic horizon and have an average annual precipitation of 22 to 24 inches.
GEOGRAPHIC SETTING: Nawt soils are on breaks. They have slopes of l5 to 75 percent. They formed in colluvium and residuum from welded tuff and volcanic ash. Elevations are 4,300 to 6,000 feet. Average annual precipitation is 12 to l6 inches. Average annual temperature is 47 to 50 degrees F. The frost free season is about l00 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Doodlelink,
Flatron,
Gosinta,
Rogerson,
Schnipper, and
Stricker soils. Doodlelink soils occur on the same landscape, but on higher,
cooler, wetter exposures, are pachic and skeletal. Flatron soils occur on ridges and dipslopes, and are shallow to bedrock. Gosinta soils occur on terraces, and are fine-loamy. Rogerson and Schnipper soils occur on terraces and toeslopes. Rogerson soils are shallow to a hardpan. Schnipper soils are moderately deep to a hardpan. Stricker soils lack an argillic horizon, and are skeletal.
DRAINAGE AND PERMEABILITY: Well drained, medium or rapid runoff; slow permeability.
USE AND VEGETATION: Nawt soils are used for rangeland. Native vegetation is bluebunch wheatgrass and Wyoming big sagebrush.
DISTRIBUTION AND EXTENT: South central Idaho. The series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES PROPOSED: Twin Falls County, Idaho, l977. Named is
coined.
REMARKS: Base saturation: 0-5 inches-76 percent; 5-10 inches-69 percent;10-18 inches-70 percent; 18-34 inches-69 percent.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 10 to 18 inches (A, Bt1, and Bt2 horizons)
Abrupt textural change - at 5 inches (A and Bt1 horizons)
Argillic horizon - 5 to 25 inches (Bt1, Bt2, and part of Bt3 horizon)
Paralithic contact - 40 to 60 inches (Cr horizon)