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JCA- San Joaquin loam, 0 to Z percent slopes. This moderately deep to hardpan, moderately well drained soil is on nearly level low terraces. It formed in alluvium from granitic rock sources. The native vegetation is mainly annual grasses, (orbs and scattered valley oaks. Slopes are a complex of gently sloping hummocks and depressions with minor drainages and areas that have been land leveled. Meandering drainageways and closed depressions that fill with water to form vernal pools in the winter months occur in many areas of this unit. Elevation is ZO to 100 feet. The average annual precipitation is about Ib inches, the average annual air temperature is about 51 degrees F, and the average frost-free period is about 275 days. Typically, the surface layer is brown loam about 6 inches thick. The upper 10 inches of the subsoil is brown loam. The lower 10 inches is brown clay. The next layer to a depth of 60 inches is a brown, light brown and strong brown indurated hardpan. Depth to hardpan ranges from ZO to 40 inches. In some areas the surface layer is fine sandy loam or loam. Included in this unit are small areas of Capay and Galt ,soils on slightly lower positions and moderately coarse textured soils with hardpan at depths of lZ to ZO inches on similar positions. Also included are small areas of San Joaquin soils on 2 to 5 percent slopes on slightly higher positions and land leveled areas that have as much as ZO inches of overburden or that have most of the soils horizons removed or altered. Included areas make up about 15 percent of the total acreage. Permeability of the San Joaquin soil is very slow. Available water capacity is low. Shrink-swell potential is high. Effective rooting depth is ZO to 40 inches but roots are restricted to cracks and faces of peds in the claypan which occurs at a depth of 10 to ZO inches. Runoff is ponded in small vernal pool areas, very slow to ponded in leveled areas, slow on convex slopes and the hazard of water erosion is slight. The water intake family for irrigation is 1.0. Water is perched for brief periods above the claypan and hardpan after heavy rains or irrigations. Most areas of this unit are used for rangeland, irrigated pastureland, irrigated cropland and vineyards. A few areas are used for dryland grain and homesite development. Where this unit is used for livestock grazing, general management considerations include saturated soil conditions in concave areas following rainy periods. The characteristic plant community on this unit is mainly soft chess, ripgut brome, foxtail fescue and filaree. Grazing should be delayed until the soil is firm enough to withstand trampling by livestock and the more desirable forage plants have had an opportunity to set seed. This unit is suited to irrigated pasture. The main limitations are complex slopes and low available water capacity. Leveling helps to insure the uniform application of water. Because this soil is droughty, applications of irrigation water should be light and frequent. Irrigation water can be applied by the sprinkler and border methods. Use of proper stocking rates, pasture rotation and restricted grazing during wet periods helps to keep the pasture in good condition and to protect the soil from compaction. This unit is suited to irrigated row, field and vineyard crops. The main limitations are complex slopes, depth to the very slowly permeable claypan and hardpan and low available water capacity. Leveling helps to insure the uniform application of water. Because of the very slow permeability of this soil, the application of water should be regulated so that water does not stand on the 'surface and damage the crops. The hardpan reduces the yield of deep rooted crops. Where feasible, deep ripping of this restrictive layer helps to overcome this limitation. A tillage pan forms easily if this soil is tilled when wet. Chiseling or subsoiling breaks up the tillage pan. Because this soil is droughty, applications of irrigation water should be light and frequent. Furrow, border, corrugation and sprinkler irrigation systems are suited to this soil. Returning crop residue to the soil or regularly adding other organic matter improves fertility, reduces crusting and increases the water intake rate. Where this unit is used for dryland grain crops, the main limitation is low rainfall during the growing season. Because precipitation is not sufficient for annual cropping, a cropping system that includes small grain and summer fallow is most suitable. Maintaining crop residue on or near the surface reduces runoff and helps to maintain soil tilth and organic matter content. If this unit is used for homesite development, the main limitations are depth to the very slowly permeable claypan and hardpan, high shrink-swell potential and low strength in the claypan. If the soils are used for septic tank absorption fields, the limitation of very slow permeability can be overcome by increasing the size of the absorption field. Use of sandy backfill for the trench and Innq absorption lines helps to compensate for the very slow permeability. The suitability of the soil for septic tank absorption fields