LOCATION BIGFROG OREstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, mesic, shallow Xeric Argidurids
TYPICAL PEDON: Typical pedon of Bigfrog very cobbly sandy clay loam - rangeland, on a 35 percent slope, at an elevation of 4680 feet. (When described on May 18, 1988 the soil was moist from 6 to 18 inches. Colors are for dry soil unless otherwise stated.)
A--0 to 3 inches; brown (10YR 5/3) very cobbly sandy clay loam, dark brown (10YR 4/3) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine, and common fine roots; many very fine and fine irregular tubular pores; 30 percent gravel and 25 percent cobbles; slightly alkaline (pH 7.6); clear smooth boundary. (2 to 5 inches thick)
Bt1--3 to 10 inches; brown (10YR 5/3) gravelly sandy clay loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure parting to weak fine subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, and common fine roots; common very fine and few fine irregular tubular pores; few faint clay films on the faces of peds; 30 percent gravel; slightly alkaline (pH 7.6); clear smooth boundary.
Bt2--10 to 18 inches; pale brown (10YR 6/3) gravelly sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine, and common fine roots; common very fine and fine irregular tubular pores; few faint clay films on the faces of peds; 25 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.8); abrupt smooth boundary. (Combined thickness of the Bt horizons is 6 to 16 inches)
Bkqm1--18 to 32 inches; extremely gravelly indurated duripan; massive; extremely hard, very rigid; violently effervescent with disseminated lime; clear smooth boundary.
Bkqm2--32 to 38 inches; extremely gravelly indurated duripan; massive extremely hard, very rigid; slightly effervescent with disseminated lime; abrupt smooth boundary. (Combined thickness of the Bkqm horizons is 6 to 20 inches.)
C--38 to 60 inches; stratified very gravelly sandy loam and very gravelly loamy sand.
TYPE LOCATION: Harney County, Oregon, about 5 miles south of Fields, Oregon, about 2,000 feet south and 1,800 feet west of the northeast corner of section 12, T. 39 S., R. 34 E., on the Ladycomb Peak quadrangle. (Long. 42 degrees, 12 minutes 11 seconds N., Long. 118 degrees 39 minutes 59 seconds W. 1927 NAD)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 52 degrees F. The soils are dry in all parts of the moisture control section one-half to three-fourths of the time when the soil temperature is above 41 degrees F. Bedrock is at a depth of greater than 60 inches. The thickness of the solum and depth to the duripan is 8 to 18 inches. The particle size control section averages 10 to 35 percent rock fragments mainly as gravel, and 25 to 35 percent clay.
The A horizon has a value of 5 or 6 dry, 3 or 4 moist and a chroma of 3 or 4 moist and dry. It is neutral to slightly alkaline. It has 20 to 30 percent clay.
The Bt horizon has a hue of 7.5YR or 10YR. It is clay loam or sandy clay loam with 25 to 35 percent clay and 10 to 35 percent rock fragments. It is slightly to moderately alkaline.
The Bkqm horizon has a hue of 7.5YR or 10YR. It is 6 to 20 inches thick.
The C horizon is stratified very gravelly sandy loam, very gravelly sandy clay loam and very gravelly loamy sand. It has 35 to 60 percent rock fragments and a clay content of 5 to 25 percent.
COMPETING SERIES: These are the Acana, Argalt, Bartome, Bruncan, Chuckridge, Chuska, Colthorp, Dewar, Grassval, Handpah, Packwood, Pipeline, Roseworth, Thoms, and Wellington soils. Acana soils have a strongly calcareous argillic horizon and are strongly or very strongly alkaline in the subsoil, duripan and substratum. Argalt, Bruncan, Chuska, Colthorp and Packwood soils have bedrock immediately under the duripan. Chuckridge, Handpah, Pipeline and Wellington soils have a mean annual soil temperature of 52 degree F or warmer and have a frost-free season of over 100 days. Grassval soils are calcareous throughout the profile. Roseworth soils have carbonates at 6 to 13 inches. Thoms soils are slightly acid or neutral and have hue of 5YR in the subsoil. Bartome soils have a duripan at 14 to 20 inches, and have 0 to 15 percent rock fragments, and 18 to 26 percent clay in the particle-size control section; this series cannot be separated adequately from Bigfrog nor can it be expanded adequately to incorporate Bigfrog soils. Dewar soils have a duripan at 14 to 20 inches and the pan is over 20 inches thick.
GEOGRAPHIC SETTING: Bigfrog soils are on fan terraces and have slopes of 8 to 40 percent. The soils formed in alluvium and colluvium from mixed igneous rocks. Elevations are 4,200 to 5,600 feet. The climate is characterized by cool, moist winters and hot, dry summers. The mean annual precipitation is 6 to 10 inches. The mean annual temperature is 45 to 49 degrees F. The frost free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brock, Dixon, Ladycomb, and McConnel series. Brock soils are loamy-skeletal and are on south facing slopes. Dixon soils are very deep. Ladycomb soils are very shallow to bedrock and are on adjacent hills. McConnel soils are very deep.
DRAINAGE AND PERMEABILITY: Well drained, moderately slow permeability.
USE AND VEGETATION: The soils are used for livestock grazing and wildlife habitat. Potential native vegetation is Wyoming big sagebrush, bluebunch wheatgrass, spiny hopsage, morman tea, and Thurber needlegrass.
DISTRIBUTION AND EXTENT: Pleistocene lake basins of southeastern Oregon; MLRA 24. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Harney County, Oregon, 1997.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon
Argillic horizon - from 3 to 18 inches (Bt1, Bt2 horizons)
Duripan - from 18 to 38 inches (Bkqm1, Bkqm2 horizons) indurated
Particle-size control section - from 3 to 18 inches (Bt1, Bt2 horizons)
Aridic soil moisture regime bordering on xeric