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30 Soil Survey
<br /> average frost-free period is about 270 days. They are moderately deep or deep to a hardpan or are
<br /> Typically, the upper 8 inches of the surface layer is very deep. They formed in alluvium derived from mixed
<br /> dark grayish brown clay loam, The lower 16 inches of rock sources. Mottles in the profile indicate somewhat
<br /> the surface layer and the subsoil to a depth of 60 poorly drained soils; however, drainage has been
<br /> inches are brown clay. In some areas the surface layer improved by levees and reclamation projects. Elevation
<br /> is clay or silty clay loam. is 20 to 30 feet. The average annual precipitation is
<br /> Included in this unit are small areas of Cogna, about 11 inches, the average annual air temperature is
<br /> Finrod, Hollenbeck, and Vignolo soils. These soils are about 60 degrees F, and the average frost-free period is
<br /> in landscape positions similar to those of the Archerdale about 260 days.
<br /> soil. Also included, on the slightly higher parts of the The surface layer is grayish brown and brown sandy
<br /> landscape, are small areas of Archerdale soils that loam or loam about 10 inches thick. The upper 30
<br /> have slopes of 3 percent. Included areas make up inches of the underlying material is light brownish gray,
<br /> about 15 percent of the total acreage. pale brown, and yellowish brown, mottled loam and clay
<br /> Permeability is slow in the Archerdale soil. Available loam. The next 10 inches is a weakly cemented to
<br /> water capacity is high. The shrink-swell potential also is strongly cemented hardpan that has been disrupted by
<br /> high. The effective rooting depth is 60 inches or more. ripping. The lower part to a depth of 60 inches is
<br /> Runoff is slow, and the hazard of water erosion is stratified light brownish gray and grayish brown loamy
<br /> - slight. The rate of water intake in irrigated areas is 0.5 sand and sandy loam. The soils are saline-sodic
<br /> inch per hour. The hazard of soil blowing is slight. The throughout. Fragments of the hardpan are common
<br /> soil is subject to rare flooding, which occurs during throughout the profile. Fragments of cemented material
<br /> years of abnormally high precipitation. are on the surface and throughout the profile in some
<br /> Most areas of this unit are used for irrigated crops or areas that have been subsoiled. deeply ripped, or
<br /> orchards. A few areas are used for homesite backhoed.
<br /> development. Included in this unit are small areas of Manteca,
<br /> This unit is suited to irrigated row, field, and orchard Timor, and Bisgani soils and medium textured soils that
<br /> crops. The main limitation is the slow permeability. do not have a hardpan and are not saline-sodic. The
<br /> Because of the restricted permeability, water included soils are in landscape positions similar to
<br /> applications should be regulated so that the water does those of the Arents. They make up about 15 percent of
<br /> not stand on the surface and damage the crops. the total acreage.
<br /> Furrow, border, and sprinkler irrigation systems are Permeability is moderate or moderately slow in the
<br /> suitable_ Returning crop residue to the soil or regularly Arents. Available water capacity is low or moderate.
<br /> - adding other organic material improves fertility, The effective rooting depth of the crops commonly
<br /> minimizes crusting, and increases the rate of water grown in the county is limited by a perched water table
<br /> intake. at a depth of 3 to 5 feet. Runoff is slow, and the hazard
<br /> If this unit is used for homesite development, the of water erosion is slight. The rate of water intake in
<br /> main limitations are the high shrink-swell potential, low irrigated areas is 1.5 inches per hour. The soils are
<br /> strength, and the slow permeability. The rare flooding is subject to rare flooding, which occurs during years of
<br /> a hazard. Properly designing foundations and footings abnormally high precipitation.
<br /> and diverting runoff away from buildings help to prevent Most areas are used for irrigated crops or pasture.
<br /> the structural damage caused by shrinking and swelling. This unit may provide wetland functions and values,
<br /> Properly designing buildings and roads can offset the These should be considered in plans for enhancement
<br /> limited ability of the soil to support a load. On sites for of wildlife habitat or land use conversion.
<br /> septic tank absorption fields, the slow permeability can This unit is suited to irrigated row and field crops.
<br /> be overcome by increasing the size of the absorption The main limitations are the saline-sodic conditions and
<br /> field. Houses, roads, and streets should be constructed the high water table. The content of salts can be
<br /> above expected flood levels. reduced by leaching, applying the proper amount of soil
<br /> This map unit is in capability units lis-3 (MLRA-17), amendments, and returning crop residue to the soils.
<br /> irrigated, and IVs-3 (MLRA-17), nonirrigated. It is in Careful applications of irrigation water are needed to
<br /> vegetative soil group A. prevent the buildup of a high water table, A drainage
<br /> system may be needed. Intensive management is
<br /> 108—Arents, saline-sodic, 0 to 2 percent slopes. required to reduce the salinity and maintain productivity.
<br /> These somewhat poorly drained, nearly level soils are Furrow, border, and sprinkler irrigation systems are
<br /> in areas on low alluvial fans or tan terraces where suitable. Returning crop residue to the soils or regularly
<br /> ripping, cutting, or filling has altered the landscape. adding other organic material improves fertility,
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