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<br /> ' San Joaquin County, California 137
<br /> t adding other organic material improves fertility, Most areas are used for irrigated crops or orchards.
<br /> minimizes crusting, and increases the rate of water A few areas are used for homesite development. This
<br /> intake. unit may provide wetland functions and values. These
<br /> If this unit is used for homesite development, the should be considered in plans for enhancement of
<br /> ' main limitations are the moderately slow permeability, wildlife habitat or land use conversion.
<br /> low strength, and depth to the hardpan. The rare This unit is suited to irrigated row, field, and orchard
<br /> flooding is a hazard. On sites for septic tank absorption crops. The main limitation is depth to the hardpan,
<br /> ' fields, the moderately slow permeability can be which limits the suitability for deep-rooted crops. Where
<br /> overcome by increasing the size of the absorption field. feasible, deep ripping of this restrictive layer can help to
<br /> Ripping the hardpan improves permeability and thus overcome this limitation. Furrow, border, and sprinkler
<br /> ' also improves the suitability of the soil for septic tank irrigation systems are suitable. Careful applications of
<br /> absorption fields. Properly designing buildings and irrigation water are needed to prevent the buildup of a
<br /> roads can offset the limited ability of the soil to support high water table. Returning crop residue to the soil or
<br /> a load. Houses, roads, and streets should be regularly adding other organic material improves fertility,
<br /> ' constructed above expected flood levels. minimizes crusting, and increases the rate of water
<br /> This map unit is in capability units Ills-8 (MLRA-17), intake.
<br /> irrigated, and IVs-8 (MLRA-17), nonirrigated. It is in If this unit is used for homesite development, the
<br /> ' vegetative soil group G. main limitations are the moderately slow permeability,
<br /> low strength, and depth to the hardpan. The rare
<br /> 271—Vignolo silty clay loam, 0 to 2 percent flooding is a hazard. On sites for septic tank absorption
<br /> slopes. This moderately well drained, nearly level soil is fields, the moderately slow permeability can be
<br /> ' on low fan terraces. It is moderately deep to a hardpan. overcome by increasing the size of the absorption field.
<br /> It formed in alluvium derived from mixed rock sources. Ripping the hardpan improves permeability and thus
<br /> A few areas are dissected by intermittent sloughs that also improves the suitability of the soil for septic tank
<br /> have been filled as a result of land leveling. Elevation is absorption fields. Properly designing buildings and
<br /> ' 40 to 110 feet. The average annual precipitation is roads can offset the limited ability of the soil to support
<br /> about 14 inches, the average annual air temperature is a load. Houses, roads, and streets should be
<br /> about 60 degrees F, and the average frost-free period is constructed above expected flood levels.
<br /> ' about 270 days. This map unit is in capability units Ills-8 (MLRA-17),
<br /> Typically, the surface layer is brown and dark grayish irrigated, and IVs-8 (MLRA-17), nonirrigated. It is in
<br /> brown silty clay loam about 14 inches thick. The upper vegetative soil group G.
<br /> ' part of the subsoil is variegated brown and pale brown
<br /> clay loam about 16 inches thick. The lower part to a 272—Vina fine sandy loam,0 to 2 percent slopes.
<br /> depth of 60 inches is a light gray, very pale brown, and This very deep, well drained, nearly level soil is on flood
<br /> pale brown, weakly cemented to strongly cemented plains. It formed in alluvium derived from mixed but
<br /> ' hardpan. In some areas the surface layer is clay loam. dominantly granitic rock sources. Elevation is 50 to 120
<br /> Included in this unit are small areas of Hollenbeck, feet. The average annual precipitation is about 16
<br /> Stockton, and Gait soils in the slightly lower landscape inches, the average annual air temperature is about 60
<br /> ' positions. Also included, in landscape positions similar degrees F, and the average frost-free period is about
<br /> to those of the dominant Vignolo soil, are small areas of 270 days.
<br /> Archerdale and Cogna soils and small areas of Vignola, Typically, the upper 9 inches of the surface layer is
<br /> soils that have a medium textured surface layer. brown fine sandy loam. The lower 28 inches is dark.
<br /> ' Included areas make up about 15 percent of the total grayish brown and brown loam. The underlying material
<br /> acreage. to a depth of 60 inches is brown loam. In some areas
<br /> Permeability is moderately slow in the Vignolo soil. the surface layer is loam.
<br /> ' Available water capacity is moderate. The effective Included in this unit are small areas of Columbia soils
<br /> rooting depth is limited by the hardpan at a depth of 20 in the slightly lower landscape positions. Also included,
<br /> to 40 inches. Depth to the water table is more than 6 in landscape positions similar to those of the Vina soil,
<br /> feet, but water may be briefly perched above the are small areas of soils that are similar to the Vina soil
<br /> ' hardpan after periods of heavy rainfall or irrigation. but have coarse textured or moderately coarse textured
<br /> Runoff is slow, and the hazard of water erosion is overwash 10 to 22 inches thick. Included areas make
<br /> slight. The rate of water intake in irrigated areas is 0.3 up about 15 percent of the total acreage.
<br /> ' inch per hour. The soil is subject to rare flooding, which Permeability is moderate in the Vina soil. Available
<br /> occurs during years of abnormally high precipitation. water capacity is high. The effective rooting depth is 60
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