LOCATION FLATRON IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, mesic Lithic Argixerolls
TYPICAL PEDON: Flatron very gravelly loam - on a slope of 3 percent under rangeland vegetation at 5,400 feet elevation. When described on September 1979, the soil was dry throughout. (Colors are for dry soil unless otherwise noted.)
A--0 to 4 inches; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, slightly sticky and slightly plastic; many very fine to coarse roots; many very fine tubular pores; 25 percent gravel, 5 percent cobbles, 5 percent stones; neutral; (pH 7.0); abrupt smooth boundary. (3 to 5 inches thick)
Bt1--4 to 6 inches; brown (10YR 5/3) very cobbly clay loam, brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; many very fine to coarse roots; common very fine tubular pores; common moderately thick clay films on faces of peds; 25 percent gravel, 20 percent cobbles, 5 percent stones; neutral (pH 7.0); clear smooth boundary.(1 to 3 inches thick)
Bt2--6 to 12 inches; brown (10YR 5/3) extremely gravelly clay, dark brown (10YR 3/3) moist; strong medium subangular blocky structure; hard, firm, sticky and plastic; few very fine to fine roots; few very fine tubular pores; common moderately thick clay films on faces of peds and in pores; 35 percent gravel, 20 percent cobbles, 10 percent stones; thin carbonate coating on underside of welded tuff fragments; mildly alkaline (pH 7.6); abrupt smooth boundary. (6 to 13 inches thick)
R--12 inches; gray (10YR 6/1) welded tuff, dark gray (10YR 4/1) moist.
TYPE LOCATION: Twin Falls County, Idaho; about 7 miles east of Hollister, Idaho; in the southeast 1/4, southwest 1/4, northeast 1/4, section 26, T. 12 S., R. 17 E.
RANGE IN CHARACTERISTICS:
Depth to the welded tuff - 10 to 20 inches
Mollic epipedon - 10 to 20 inches
Average clay percent in the control section - 50 to 60
Average annual soil temperature - 47 to 50 degrees F.
A horizon
Color value, moist - 2 or 3
Chroma - 2 or 3 dry or moist
Structure type - granular or platy
Gravel - 25 to 40 percent
Cobbles - 5 to 10 percent
Stones - 5 to 10 percent
Organic matter content - 2 to 4 percent
Bt horizon
Color Chroma, dry or moist - 2 or 3
Structure Type - subangular blocky or angular blocky
Gravel - 20 to 40 percent
Cobbles - 20 to 25 percent
Stones - 5 to 15 percent
Texture - CBV-CL, CBV-C, CBX-CL, CBX-C
COMPETING SERIES: These are the Camaspatch (T), Gwinly, Laufer, Longcreek (T), Loomer, Lorella, Pioche, Ruckles, Vantage (T), and Waterbury series. Camaspatch soils are very gravelly or extremely gravelly in the Bt horizon. Gwinly, Laufer, Loomer, Lorella, and Pioche soils have less than 50 percent clay in the argillic horizon. Ruckles soils have 1 to 2 percent organic matter content in the A horizon and a mollic epipedon that is less than 10 inches thick. Vantage soils have a mollic epipedon that is less than 10 inches thick and a Btq horizon. Waterbury soils are usually moist and have A horizons with dry values of 3 or 4, and moist values closest to 2.
GEOGRAPHIC SETTING: Flatron soils are on ridges and dipslopes. The slopes range from 2 to 20 percent. The soils formed in residuum from welded tuff. Elevations are 5,000 to 5,700 feet. The average annual precipitation ranges from 14 to 16 inches. The average annual temperature is 45 to 48 degrees F. The frost free season is 100 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Nawt, Ragpie, and Stricker soils. Nawt soils are not skeletal and occur on breaks. Ragpie soils occur on the same landscape, and are loamy-skeletal. Stricker soils are loamy-skeletal, and occur on breaks.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff; slow permeability.
USE AND VEGETATION: Flatron soils are used for rangeland. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, low sagebrush, and Wyoming big sagebrush.
DISTRIBUTION AND EXTENT: Flatron soils are of small extent in south central Idaho.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES PROPOSED: Twin Falls County, Idaho, 1981. The name is coined from an elevation marker.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 12 inches (A, Bt1, and Bt2 horizons)
Argillic horizon - 4 to 12 inches (Bt1 and Bt2 horizons)
Lithic contact - 12 inches (R horizon)