ANR Shafter REC - Soil & Geology

Soil & Geology

SREC is dominated by one soil series, Wasco sandy loam. The Wasco series covers 109,000 acres or 8% of the land area in Northwestern Kern County. It consists of deep, well drained soil on recent alluvial fans and flood plains. These soils formed in alluvium derived dominantly from granitic rock. Slope is 0 to 5%. It is a poor to very poor habitat for wildlife and most plant life in the absence of irrigation. The first foot of soil has a pH of about 6.8. Below 2 feet, there is some cabonate and organic matter is less than 1%. Both nitrogen content and salinity are very low and no toxic elements are present. Field capacity is 17% by volume, and permanent wilting point (PWP) is 5%.

Soils of the Wasco series are coarse-loamy, mixed, nonacid, thermic Typic Torriorthents.

soilprofile.jpg (59779 bytes) The typical pedon of the Wasco series is described as follows:

Ap1 0-9 inches; brown (10YR 5/3) sandy loam, dark grayish brown (10YR 4/2) moist, massive; slightly hard, very friable, nonsticky and nonplastic; very few very fine roots; many very fine interstitial pores; slightly acid; abrupt smooth boundary.

Ap2 9-15 inches; yellowish brown (10 YR 5/4) sandy loam, dark grayish brown (10 YR 4/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; very few fine roots; few very fine tubular pores and many very fine interstitial pores; neutral; abrupt smooth boundary.

C1 15-32 inches; brown (10 YR 5/3) sandy loam, dark grayish brown (10 YR 4/2) moist; massive; slightly hard, very friable, nonsticky and nonplastic; very few very fine roots; common very fine tubular pores and many very fine interstitial pores; neutral; abrupt smooth boundary.

C2 32-65 inches; pale brown (10 YR 6/3) sandy loam, brown (10YR 4/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; common very fine tubular pores and many very fine interstitial pores; slightly effervescent; disseminated lime; moderately alkaline.

Carbonates are not present in all pedons to a depth of 16 to 40 inches. Lime is disseminated below a depth of 16 to 40 inches. The profile is less than 15% rock fragments to a depth of 40 inches or more. Rock fragments are less than 0.5 inch in diameter.

The A horizon has dry color of 10 YR 5/2, 5/3, 5/4, 6/2, or 6/3 or 2.5 Y 5/2 or 6/2 and moist color of 10 YR 3/2, 3/3, 3/4, 4/2, or 5/3. Clay content is 8 to 18%. The A horizon commonly is massive, but it is blocky or platy in some pedons. Reaction is slightly acid to mildly alkaline.

The C horizon has dry color of 10 YR 5/3, 5/4, 6/3, 6/4 or 2.5 Y 5/4 and moist color of 10 YR 4/3, 4/4, 5/2, or 5/3, or 6/1 or 2.5 Y 4/4. Texture is mainly sandy loam or fine sandy loam, but it is stratified loamy sand to silt loam below a depth of 40 inches in some pedons. Clay content is 8 to 18%. Reaction is neutral to moderately alkaline.

Other physicial and chemical characteristics include:

Characteristic	Unit	0-15 inches	15-60 inches
Clay	%	8 - 18	8 - 18
Organic Matter	%	0.5	<0.5
Permeability	In/hr	2.0 - 6.0	2.0 - 6.0
Available Water Holding Capactiy	In/In	0.08 - 0.11	0.08 - 0.11
Soil Reaction	pH	6.1 - 7.8	6.6 - 8.4
Erosion Factor	K	0.32	0.32
T Factor		5	5
Salinity	mmhos/cm	<2	<2
Shrink/Swell Potential		low	low

Source:USDA-SCS, Soil Survey of Kern County, California Northwestern Part

ANR Shafter Research and Extension Center