LOCATION COFF NV
Established Series
Rev. ELS/RLB/JBF
02/2016
COFF SERIES
The Coff series consists of moderately deep over petrocalcic horizon, well drained soils that formed in material derived from calcareous shale and limestone. The Coff soils are on mountain foothill slopes and have 30 to 50 percent slopes. The mean annual precipitation is about 280 mm and the mean annual temperature is about 7 degrees C.
TAXONOMIC CLASS: Loamy-skeletal, carbonatic, frigid Calcic Petrocalcids
TYPICAL PEDON: Coff extremely gravelly silt loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 5 cm; light brownish gray (10YR 6/2) extremely gravelly silt loam, dark grayish brown (10YR 4/2) moist; strong medium platy structure; slightly hard, very friable, nonsticky, slightly plastic; many very fine and fine roots; many very fine and fine, and few medium vesicular pores; 60 percent gravel; slightly effervescent; moderately alkaline (pH 8.2); abrupt smooth boundary. (3 to 10 cm thick)
A2--5 to 13 cm; light brownish gray (10YR 6/2) very gravelly silt loam, dark grayish brown (10YR 4/2) moist; moderate very thin platy structure; soft, very friable, nonsticky, slightly plastic; many very fine and fine roots; many very fine interstitial, and few medium tubular pores; 50 percent gravel; strongly effervescent; moderately alkaline (pH 8.2); clear smooth boundary. (5 to 15 cm thick)
Bk1--13 to 25 cm; pale brown (10YR 6/3) extremely gravelly silt loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; many very fine, common fine, and few medium roots; few very fine and medium tubular pores; 60 percent gravel; few fine and medium soft masses of carbonate; violently effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (18 to 18 cm thick)
Bk2--25 to 51 cm; very pale brown (10YR 7/3) extremely gravelly silt loam, brown (10YR 5/3) moist; massive; hard, friable, nonsticky, slightly plastic; many very fine and fine roots; few fine and very fine tubular pores; 60 percent gravel; common fine and medium soft masses of carbonate; all gravel are coated with carbonate up to 0.6 cm thick; violently effervescent; moderately alkaline (pH 8.2); clear wavy boundary. (20 to 36 cm thick)
Bk3--51 to 74 cm; very pale brown (10YR 7/3) very gravelly silt loam, brown (10YR 5/3) moist;; massive; soft, very friable, slightly sticky, nonplastic; many very fine and few fine roots; few fine tubular pores; 70 percent gravel; many medium and large soft distinct, very pale brown (10YR 8/2), masses of carbonate and carbonate coated gravel; violently effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (18 to 30 cm thick)
Bkm1--74 to 84 cm; very pale brown (10YR 8/3) lenticular discontinuous strongly cemented carbonate hardpan, pale brown (10YR 6/3) moist; massive; very hard, very firm; few medium and very fine roots matting between plates; violently effervescent; strongly alkaline (pH 8.6); very abrupt wavy boundary. (5 to 20 cm thick)
Bkm2--84 to 97 cm; very pale brown (10YR 8/3) indurated carbonate hard pan, pale brown (10YR 6/3) moist, with continuous laminar capping that is very pale brown (10YR 7/4) and dark yellowish brown (10YR 4/4) moist; extremely hard, extremely firm; very few very fine roots matted between plates; violently effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Eureka County, Nevada; approximately 2,200 feet south and 1,950 feet east of the northwest corner of section 27, T.35N. R.50E.; USGS Rodeo Creek NE 7.5 minute topographic quadrangle; latitude 40 degrees 52 minutes 57 seconds N and longitude 116 degrees 20 minutes 42 seconds W; WGS84 Decimal Degrees 40.8825000 latitude, -116.3450000 longitude.
RANGE IN CHARACTERISTICS:
Soil moisture: Usually dry; intermittently moist in winter and spring; Typic aridic soil moisture regime.
Mean annual soil temperature: 7 to 8 degrees C.
Depth to the petrocalcic horizon: 60 to 90 cm.
Particle-size control section - Clay content: 10 to 15 percent.
Rock Fragments: 60 to 75 percent gravel. Lithology of the fragments is limestone.
A horizons
Chroma of 2 or 3.
Bk horizons
Value 6 or 7 dry, 4, through 6 moist.
Chroma: 2 or 3.
Texture: Loam or silt loam.
Calcium carbonate equivalent of the less than 20 mm fraction: 40 to 60 percent.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: The Coff soils are on mountain foothill slopes at elevations of 1,830 to 1,980 meters. The soils have formed in material derived from calcareous shale and limestone, with some influence from loess high in volcanic ash. The average annual temperature is 6 to 7 degrees C; average annual precipitation is about 250 to 300 mm; and frost-free season is about 90 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: This is the
Denay series. Denay soils have mollic epipedons.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderate permeability; moderately high saturated hydraulic conductivity.
USE AND VEGETATION: Used for livestock grazing and wildlife habitat. The vegetation is principally black sagebrush, bluebunch wheatgrass, Sandberg bluegrass and squirreltail.
DISTRIBUTION AND EXTENT: Northcentral Nevada. MLRA 24 and 25. These soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Eureka County (Tuscarora Mountain Area), Nevada, l968.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Xeric feature - meets the soil moisture regime and organic carbon requirements of "Xeric".
Ochric epipedon - The Zone from 0 to 18 cm (A and part of the Bk1 horizons).
Calcic horizons - The zone from 13 to 74 cm (Bk1, Bk2 and Bk3 horizons).
Petrocalcic horizons - the zone from 74 to 97 cm (Bkm1 and Bkm2 horizons).
Particle-size control section - The zone from 25 to 74 cm (Bk2 and Bk3 horizons).
National Cooperative Soil Survey
U.S.A.