LOCATION RINCONFLAT              OR

Established Series
Rev. MPK-TDT-JVC-JBF
06/2011

RINCONFLAT SERIES

The Rinconflat series consists of very deep, well drained soils that formed in alluvium derived from mixed volcanic rocks. Rinconflat soils are on alluvial fans and fan remnants. Slopes are 3 to 10 percent. The mean annual precipitation is about 280 mm and the mean annual temperature is about 7 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Xeric Haplocambids

TYPICAL PEDON: Rinconflat stony loam--on a 5 percent slope at an elevation of about 1,561 meters--rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 10 cm; pale brown (10YR 6/3) stony loam, dark brown (10YR 3/3) moist; moderate thick platy structure parting to moderate medium granular; slightly hard, friable, slightly sticky and slightly plastic; common very fine roots; many fine irregular pores; 15 percent gravel, 5 percent cobbles, and 10 percent stones; neutral (pH 6.9); clear wavy boundary. (8 to 20 cm thick)

Bw1--10 to 33 cm; yellowish brown (10YR 5/4) gravelly loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and common fine roots; many fine and medium irregular pores; 20 percent gravel; neutral (pH 7.2); clear wavy boundary.

Bw2--33 to 58 cm; yellowish brown (10YR 5/4) very cobbly loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common fine, few very fine and medium roots; many very fine and fine irregular pores; 20 percent gravel and 20 percent cobbles; neutral (pH 7.2); gradual wavy boundary.

Bw3--58 to 74 cm; yellowish brown (10YR 5/4) very gravelly loam, dark yellowish brown (10YR 3/4) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine roots; many very fine and fine irregular pores; 35 percent gravel, 15 percent cobbles and 5 percent stones; slightly alkaline (pH 7.7); clear wavy boundary. (Combined thickness of the Bw horizons is 40 to 80 cm)

2Cq--74 to 145 cm; pale brown (10YR 6/3) cobbly sandy loam, dark yellowish brown (10YR 3/4) moist; massive; slightly hard, firm, nonsticky and nonplastic; 10 percent silica cemented nodules; few fine roots; few fine irregular pores; 15 percent gravel and 10 percent cobbles; slightly effervescent; strongly alkaline (pH 8.8); clear wavy boundary.

2C--145 to 155 cm; yellowish brown (10YR 5/4) very cobbly sandy clay loam, dark brown (7.5YR 3/4) moist; massive; slightly hard, friable, slightly sticky and nonplastic; few fine irregular pores; 20 percent gravel and 25 percent cobbles; slightly effervescent; strongly alkaline (pH 8.5).

TYPE LOCATION: Harney County, Oregon; south of Dip Creek between Rincon Flat and the Pueblo Mountains; about 2,000 feet south and 2,000 feet east of the northwest corner of section 25, T. 39 S., R. 33 E.; USGS Rincon Flat 7.5 minute topographic quadrangle; latitude 42 degrees 09 minutes 36 seconds N and longitude 118 degrees 47 minutes 27 seconds W; NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Usually moist in the moisture control section in winter and spring, dry in summer and fall; These soils are dry in all parts of the moisture control section one-half to three-fourths of the time when the soil temperature is greater than 5 degrees C.; aridic moisture regime that borders on xeric.
Mean annual soil temperature: 7 to 8 degrees C.
Depth to base of cambic horizon: 50 to 100 cm.
Depth to horizons with free carbonates: 50 to 100 cm.
Depth to bedrock: Greater than 150 cm.

Particle-size control section - Clay content: 18 to 27 percent.
Rock fragments: Averages 35 to 60 percent, mainly gravel and cobbles. Lithology of fragments are volcanic rocks such as basalt and tuff.

A horizon
Value: 4 through 6 dry, 3 or 4 moist.
Chroma: 2 through 4, dry or moist..

Bw horizons
Hue: 7.5YR or 10YR.
Value: 5 or 6 dry, 3 or 4 moist.
Texture: Gravelly loam, very gravelly loam, very gravelly sandy clay loam, or very cobbly loam.
Clay content: 18 to 27 percent.
Rock fragments: 20 to 60 percent.
Reaction: Neutral or slightly alkaline.

2Cq and 2C horizons
Hue: 10YR or 7.5YR.
Value: 3 or 4 moist.
Chroma: 3 or 4, dry or moist
Texture: Cobbly sandy loam, very cobbly sandy clay loam, or very gravelly sandy loam.
Clay content: 10 to 27 percent.
Rock fragments: 25 to 60 percent.
Reaction: Moderately alkaline or strongly alkaline.
Other features: Some pedons have less than 20 percent by volume weakly cemented matrix or durinodes.

COMPETING SERIES: These are the Oreneva, Packham, and Rutab series.

Oreneva soils are moderately deep to lithic contacts. Packham soils have 12 to 18 percent clay in the particle-size control section and have very gravelly or extremely gravelly coarse sand or loamy sand within 100 cm of the soil surface. Rutab soils have 5 to 18 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Rinconflat soils are on alluvial fans and fan remnants. These soils formed in alluvium derived from mixed volcanic rocks. Slopes are 3 to 10 percent. Elevations range from 1,290 to 1,740 meters. The climate is semiarid and characterized by cool, moist winters and warm, dry summers. The mean annual precipitation is 250 to 300 mm, the mean annual temperature is 6 to 7 degrees C, and the frost-free period is 50 to 80 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carvix, Fourwheel, Lonely, and Robson soils. Carvix soils are fine-loamy, have mollic epipedons, and are in drainages. Fourwheel and Robson soils are moderately deep. Lonely soils are shallow. Fourwheel, Lonely, and Robson soils are on hills and plateaus.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; medium surface runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: Rinconflat soils are used for livestock grazing and wildlife habitat. The potential native vegetation is Wyoming big sagebrush, Thurber's needlegrass, and Sandberg's bluegrass.

DISTRIBUTION AND EXTENT: South-central Oregon. These soils are moderately extensive. MLRA 23.

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 - The zone from the soil surface to 18 cm (A horizon and part of the Bw1 horizon).
Cambic horizon - The zone from 10 to 74 cm (Bw1, Bw2, and Bw3 horizons).
Particle-size control section - The zone from 25 to 100 cm (Bw2 and Bw3 horizons and parts of the Bw1 and 2Cq horizons).

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National Cooperative Soil Survey
U.S.A.