LOCATION REYWAT ID+CA NV OR UTEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Argixerolls
TYPICAL PEDON: Reywat very stony loam--rangeland. (Colors are for dry soil unless otherwise noted).
A1--0 to 3 inches; grayish brown (10YR 5/2) very stony loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine and many fine irregular pores; 20 percent gravel, 15 percent cobbles, and 20 percent stones; neutral (pH 6.6); clear smooth boundary. (2 to 8 inches thick)
A2--3 to 6 inches; grayish brown (10YR 5/2) very stony loam, dark brown (10YR 3/3) moist; moderate coarse granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine roots; many fine irregular pores; 20 percent gravel, 15 percent cobbles, and 20 percent stones; neutral (pH 6.6); clear wavy boundary. (0 to 4 inches thick )
Bt1--6 to 14 inches; brown (10YR 5/3) very gravelly clay loam, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine roots; common very fine tubular pores; many distinct dark yellowish brown (10YR 3/4) clay films on faces of peds; 40 percent gravel and some cobbles; neutral (pH 6.6); clear wavy boundary. (2 to 8 inches thick)
Bt2--14 to 19 inches; brown (10YR 5/3) very gravelly clay loam, dark brown (10YR 3/3) moist; strong medium subangular blocky structure; hard, friable, sticky and plastic; common very fine roots; common very fine tubular pores; many distinct dark yellowish brown (10YR 3/4) clay films on faces of peds; 40 percent gravel and some cobbles; neutral (pH 6.6); abrupt irregular boundary. (4 to 9 inches thick)
R--19 inches; basalt; slightly weathered in upper few inches; slightly effervescent on the surface of the contact and in some cracks where secondary carbonates are present.
TYPE LOCATION: Washington County, Idaho; about 10 miles northwest of Weiser; approximately 215 feet south and 125 feet east of the northwest corner of section 19, T. 12 N., R. 6 W.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section for 60 consecutive days or more during the 3 month period following the winter solstice and dry for 60 to 80 consecutive days during the 3 month period following the summer solstice; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 47 to 54 degrees F.
Mean summer soil temperature - 65 to 71 degrees F.
Mollic epipedon thickness - 7 to 18 inches; includes parts of the Bt horizons in some pedons.
Depth to base of argillic horizon - 10 to 20 inches.
Depth to bedrock - 10 to 20 inches to a lithic contact.
Control section - Clay content: 24 to 35 percent;
Rock fragments: averages 35 to 60 percent, mainly gravel and cobbles. Lithology of fragments are mainly basalt and similar volcanic rocks.
Base saturation - greater than 75 percent.
A horizons
Hue: 10YR or 7.5YR.
Value: 4 through 6 ( averages 5.5 or less when mixed) dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Reaction: Neutral to moderately alkaline.
Organic matter content: 1 to 4 percent.
Other features: Some pedons have vesicular pores in the upper 1 or 2 inches.
Bt horizons
Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 2 through 4 moist.
Chroma: 2 or 3, dry or moist.
Texture: Very gravelly clay loam, very gravelly loam, very gravelly sandy clay loam, very cobbly clay loam, very cobbly loam, very cobbly sandy clay loam, very stony clay loam, or extremely cobbly clay loam; Average size and quantity of fragments often increases with depth.
Clay content: 24 to 35 percent.
Rock fragments: 35 to 70 percent.
Reaction: Neutral to moderately alkaline.
Organic matter content: 0 to 2 percent.
Effervescence: Slightly effervescent or strongly effervescent in the lower part of the Bt2 horizon, on the surface of the lithic contact, or in cracks within the bedrock, where identifiable secondary carbonates are present.
Calcium carbonate equivalent: 0 to 2 percent.
COMPETING SERIES: These are the Argabak, Bellehelen, Brier, Canfire, Chinabutte, Clovercreek, Duco, Gwin, Horseflat, Ocud (T), Orhood, Shepridge, Stepmount, Upatad, and Windry series.
Argabak soils have mollic epipedons 5 to 7 inches thick and do not have identifiable secondary carbonates in the lower part of the Bt2 horizon, on the surface of the lithic contact, or in cracks within the bedrock. Bellehelen and Brier soils are intermittently moist for 10 to 20 cumulative days between July and October due to convection storms. Canfire, Chinabutte, Clovercreek, Gwin, Shepridge, Stepmount, and Windry soils have a xeric moisture regime. Duco and Orhood soils do not have identifiable secondary carbonates in the lower part of the argillic horizon, on the surface of the lithic contact, or in cracks within the bedrock. Horseflat soils do not have identifiable secondary carbonates in the lower part of the Bt horizon, on the surface of the lithic contact, or in cracks within the bedrock. Ocud soils average 15 to 25 clay and 60 to 80 percent rock fragments in the particle-size control section and do not have identifiable secondary carbonates in the lower part of the Bt horizon, on the surface of the lithic contact, or in cracks within the bedrock. Upatad soils have horizons with significant accumulations of identifiable secondary carbonates and secondary silica.
GEOGRAPHIC SETTING: Reywat soils are hills, mountains, and plateaus. They formed dominantly in residuum derived from andesite, basalt or similar volcanic rocks. On steep slopes, colluvium is a major portion of the parent material. Other areas have minor amounts of loess or volcanic ash in the A horizons. Slopes are 0 to 90 percent. Most slopes have south aspects, but some face north, especially at the lower elevations. Elevations range from 1,000 to 7,630 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 9 to 14 inches, including 1.5 to 5 feet of snowfall. The mean annual temperature is 45 to 52 degrees F. The frost-free period is 80 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Babbington, Bakeoven, Lickskillet, Ruckles, and Ruclick soils. Babbington soils lack bedrock and have less than 35 percent rock fragments in the argillic horizon. Bakeoven and Lickskillet soils are less than 10 inches deep. Ruckles and Ruclick soils are in a clayey family.
DRAINAGE AND PERMEABILITY: Well drained; very high surface runoff; moderately slow permeability (moderately high saturated hydraulic conductivity).
USE AND VEGETATION: Reywat soils are used mainly for rangeland. The vegetation is mainly big sagebrush, Sandberg's bluegrass, bluebunch wheatgrass, cheatgrass, bottlebrush squirreltail, wild mustard, yarrow, wild buckwheat, phlox, and other forbs.
DISTRIBUTION AND EXTENT: Southwestern Idaho, northeastern California, northern Nevada, eastern Oregon, and western Utah. These soils are extensive with about 260,000 acres of the series mapped to data. MLRAs 10, 11, 23, 25, 26, 27, 28A, and 47. The original series concept and type location is in MLRA 10.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Payette County, Idaho, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 7 inches (A1 and A2 horizons and part of the Bt1 horizon).
Argillic horizon - The zone from 6 to 19 inches (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 19 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 6 to 19 inches (Bt1 and Bt2 horizons).