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San Joaquin County, California 59
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<br /> to lateral seepage in wet years when the water level is or regularly adding other organic material improves
<br /> high. Careful applications of irrigation water are needed fertility, minimizes crusting, and increases the rate of
<br /> to prevent the buildup of a high water table. Tile water intake.
<br /> drainage can lower the water table if a suitable outlet is If this unit is used for homesite development,, t P , the
<br /> available. Furrow, border, and sprinkler irrigation main limitations are the slow permeability, low strength,
<br /> systems are suitable. When the wind velocity is high in and the high shrink-swell potential. On sites for septic
<br /> spring, the hazard of soil blowing can be reduced by tank absorption fields, the slow permeability can be
<br /> properly managing all crop residue and by minimizing overcome by increasing the size of the absorption field,
<br /> tillage. backfilling the trench with sandy material, and installing
<br /> The Egbert soil is in capability units Ilw-2 (MLRA-17), long absorption lines. Properly designing buildings and
<br /> T irrigated, and IVw-2 (MLRA-17), nonirrigated. It is in roads can offset the limited ability of the soil to support
<br /> vegetative soil group C. The Urban land is not assigned a load. Properly designing foundations and footings and
<br /> a capability classification or a vegetative soil group. diverting runoff away from buildings help to prevent the
<br /> structural damage caused by shrinking and swelling.
<br /> 156—El Solyo clay loam, 0 to 2 percent slopes. Where this unit is used for dryland grain crops, the
<br /> This very deep, well drained, nearly level soil is on low main limitation is low rainfall during the growing season.
<br /> alluvial fans. It formed in alluvium derived from Because the amount of precipitation is not sufficient for
<br /> sedimentary rock sources. Elevation is 60 to 300 feet. annual cropping, the best suited cropping system is one
<br /> The average annual precipitation is about 10 inches, that includes small grain and summer fallow.
<br /> the average annual air temperature is about 60 degrees Maintaining crop residue on or near the surface helps to
<br /> F, and the average frost-free period is about 270 days. prevent excessive runoff and helps to maintain tilth and
<br /> Typically, the surface layer is grayish brown clay the organic matter content.
<br /> ` loam about 10 inches thick. The subsoil to a depth of This map unit is in capability units Its-3 (MLRA-17),
<br /> i= 60 inches is brown and pale brown silty clay loam. The irrigated, and IVs-3 (MLRA-17), nonirrigated. It is in
<br /> "soil is calcareous between depths of 10 and 60 inches. vegetative soil group A.
<br /> In some areas the surface layer is silty clay loam.
<br /> Included in this unit are small areas of Stomar, 157—Exeter sandy loam, 0 to 2 percent slopes.
<br /> `.` Vernalis, and Zacharias soils on the slightly higher parts This moderately well drained, nearly level soil is on low
<br /> of the landscape. Also included, in landscape positions terraces. It is moderately deep to a hardpan. It formed
<br /> similar to those of the EI Solyo soil, are small areas of in alluvium derived from mixed rock sources. A few
<br /> soils that have a moderately fine textured surface layer areas are dissected by intermittent sloughs that have
<br /> "and have a gravelly or very gravelly moderately fine been filled as a result of land leveling. Elevation is 20 to
<br /> textured substratum below a.depth of 40 inches. 100 feet. The average annual precipitation is about 15
<br /> Included areas make up about 15 percent of the total inches, the average annual air temperature is about 60
<br /> `eacreage. degrees F, and the average frost-free period is about
<br /> 4 ", Permeability is slow in the EI Solyo soil. Available 270 days.
<br /> k,..Water
<br /> high. ca acit Yis very high. The shrink-swell potential is Typically, the surface layer and the upper'part of the
<br /> The effective rooting depth is 60 inches or more. subsoil are dark brown and brown sandy loam about 26
<br /> :Runoff is slow , and the hazard of water erosion is inches thick. The next part of the subsoil is brown
<br /> slight. The rate of water intake in irrigated areas is 0.5 sandy clay loam and loam about 7 inches thick. The
<br /> inch per hour. lower part to a depth of 60 inches is a brown, indurated
<br /> Most areas of this unit are used for irrigated crops or hardpan_ In some areas the surface layer is loam.
<br /> orchards. A few areas are used for homesite Included in this unit are small areas of Kingdon and
<br /> `development or for dryland grain crops. Acampo soils in the slightly lower landscape positions
<br /> -This unit is suited to irrigated row, field, and orchard and Madera and San Joaquin soils on terraces. Also
<br /> reps The main limitation is the slow permeability. included are a few areas where depth to the hardpan is
<br /> :Because of the restricted permeability, water as little as 15 inches, mainly where deep leveling cuts
<br /> applications should be regulated so that the water does have been made. Included areas make up about 15
<br /> not,stand on the surface and damage the crops. The percent of the total acreage.
<br /> ,soil should be cultivated only within a narrow range of Permeability is moderate in the Exeter soil. Available
<br /> rrioisture content. It is too sticky when wet and too hard water capacity is low. The effective rooting depth is
<br /> when dry. Furrow, border, and sprinkler irrigation limited by the hardpan at a depth of 20 to 40 inches.
<br /> -systems are suitable. Returning crop residue to the soil Depth to the water table is more than 6 feet, but water
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