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L, i can Joaquin County, California 103 hazard of erosion, and the very low available ,nater to a depth of 60 inches is a reddish yellow and capacity. The characteristic plant community is mainly yellowish red, indurated hardpan. In some areas the soft chess, ripgut brome, (oxtail fescue, and filaree. surface layer is gravelly sandy loam, cobbly loam, or ` Grazing should be delayed until the soil is firm enough loam. to withstand trampling by livestock and the more Included in this unit are small areas of Bellota and desirable forage plants have had an opportunity to set Pardee soils on terraces and shallow, medium textured seed. Grazing should be controlled so that desirable soils that have a claypan at a depth of 10 to 15 inches ` vegetation, such as soft chess, is maintained and and are in landscape positions similar to those of the enough vegetation is left standing to protect the soil Redding soil. Also included are small areas of Alamo from erosion. The very low available water capacity and Yellowlark soils in drainageways, Pentz soils on the L limits the production of desirable forage plants. slightly higher terraces, Peters soils in the slightly lower This unit is suited to irrigated pasture. The main landscape positions, and Redding soils that have slopes limitation is the very low available water capacity. of 2 to 8 percent and are on toe slopes. Included areas General management considerations include the hazard make up about 15 percent of the total acreage. of erosion. Because the soil is droughty, applications of Permeability is very slow in the Redding sail. irrigation water should be light and frequent. The water Available water capacity is very low. The shrink-swell can be applied by sprinkler and border methods. potential is high. The effective rooting depth is limited Seedbed preparation should be on the contour or by the hardpan at a depth of 20 to 40 inches. Roots are across the slope where practical. Proper stocking rates, restricted to cracks and the faces of peds in the pasture rotation, and restricted grazing during wet claypan, which is at a depth of 16 to 22 inches. Water L periods help to keep the pasture in good condition and is briefly perched above the claypan after periods of protect the soil from erosion. heavy rainfall. Runoff is medium or rapid, and the Where this unit is used for dryland grain crops, the hazard of water erosion is moderate or severe. main limitation is low rainfall during the growing season. Most areas are used for livestock grazing. This unit General management considerations include the hazard may provide wetland functions and values. These of erosion. Because the amount of precipitation is not should be considered in plans for enhancement of sufficient for annual cropping, the best suited cropping wildlife habitat or land use conversion. L system is one that includes small grain and summer Where this unit is used for livestock grazing, general fallow. All tillage should be on the contour or across the management considerations include the hazard of slope. Limiting tillage during seedbed preparation and erosion and the very low available water capacity. The L during the application of weed-control measures helps characteristic plant community is mainly soft chess, to control runoff and erosion. Leaving crop residue on ripgut brome, foxtail fescue, and filaree. Grazing should or near the surface helps to conserve moisture, be controlled so that desirable vegetation, such as soft maintain tilth, and control erosion. chess, is maintained and enough vegetation is left This map unit is in capability unit IVe-3 (MLRA-17), standing to protect the soil from erosion. Loss of the irrigated and nonirrigated. It is in vegetative soil group surface layer results in a severe decrease in D. productivity and in the potential of the unit to produce plants suitable for grazing. The very low available water 221—Redding gravelly loam, 8 to 30 percent capacity limits the production of desirable forage plants. slopes. This moderately well drained, rolling to This map unit is in capability unit IVe-3 (MLRA-17), L moderately steep soil is on dissected high terraces. It is nonirrigated. It is in vegetative soil group D. moderately deep to a hardpan. It formed in alluvium derived from mixed rock sources. The native vegetation 222—Reiff fine sandy loam, 0 to 2 percent slopes, ` is mainly annual grasses and forbs. Slopes are occasionally flooded. This very deep, well drained, complex, and the landscape is characterized by nearly level soil is on flood plains. It formed in alluvium hummocky microrelief. Elevation is 130 to 350 feet. The derived from mixed rock sources. Elevation is 80 to 165 Laverage annual precipitation is about 17 inches, the feet. The average annual precipitation is about 16 average annual air temperature is about 60 degrees F. inches, the average annual air temperature is about 60 and the average frest-free period is about 260 days. degrees F, and the average frost-free period is about Typically. the upper part of the surface layer is strong 270 days. brown gravelly loam about 7 inches thick. The lower Typically, the surface layer is brown fine sandy loam part is reddish yellow gravelly loam about 9 inches about 9 inches thick. The upper 47 inches of the Lthick. The upper part of the subsoil is a claypan of underlying material is brown and pale brown, stratified reddish brown clay about 6 inches thick. The lower part loamy sand and sandy loam. The lower part to a depth