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<br /> 76 Soil Survey
<br /> ' restricted permeability, water applications should be The Jacktone soil is moderately deep to a hardpan
<br /> regulated so that the water does not stand on the and is somewhat poorly drained. It formed in alluvium
<br /> surface and damage the crops. The hardpan limits the derived from mixed rock sources. Mottles in the profile
<br /> ' suitability for deep-rooted crops. Where feasible, deep indicate a somewhat poorly drained soil; however,
<br /> ripping of this restrictive layer can help to overcome this drainage has been improved by levees and reclamation
<br /> limitation. The soil should be cultivated only within a projects. Typically, the surface layer is very dark gray
<br /> narrow range of moisture content. It is too sticky when and dark gray clay about 22 inches thick. The upper 12
<br /> wet and too hard when dry. Furrow, border, and inches of the subsoil is dark gray clay and light gray
<br /> sprinkler irrigation systems are suitable. Returning crop clay loam. The next 3 inches is a light gray, strongly
<br /> residue to the soil or regularly adding other organic cemented to indurated hardpan. The next 9 inches is
<br /> ' material improves fertility, minimizes crusting, and yellowish brown loam. The lower part to a depth of 60
<br /> increases the rate of water intake. inches is a yellowish brown, weakly cemented hardpan.
<br /> This unit is suited to irrigated pasture. Irrigation water In some areas the surface layer is silty clay or silty clay
<br /> can be applied by sprinkler and border methods. loam.
<br /> ' Leveling helps to ensure a uniform application of water. Permeability is slow in the Jacktone soil. Available
<br /> Proper stocking rates, pasture rotation, and restricted water capacity is moderate. The shrink-swell potential is
<br /> grazing during wet periods help to keep the pasture in high. The effective rooting depth is limited by the
<br /> good condition and protect the soil from compaction. hardpan at a depth of 20 to 40 inches. Depth to the
<br /> If this unit is used for urban development, the main waterlable is more than 5 feet, but water may be briefly
<br /> limitations are the high shrink-swell potential, the slow perched above the hardpan after periods of heavy
<br /> permeability, depth to the hardpan, and low strength. rainfall or irrigation. Runoff is slow, and the hazard of
<br /> ' The rare flooding is a hazard. Properly designing water erosion is slight. The rate of water intake in
<br /> foundations and footings and diverting runoff away from irrigated areas is 0.1 inch per hour. The soil is subject
<br /> buildings help to prevent the structural damage caused to rare flooding,which occurs during years of
<br /> ' by shrinking and swelling. On sites for septic tank abnormally high precipitation.
<br /> absorption fields, the slow permeability can be Urban land consists of areas covered by roads,
<br /> overcome by increasing the size of the absorption field. driveways, sidewalks, parking lots, buildings, and other
<br /> Ripping the hardpan improves permeability and thus structures. The soil material under the impervious
<br /> ' also improves the suitability of the soil for septic tank surface is similar to that of Jacktone clay.
<br /> absorption fields. Properly designing buildings and Most areas are used for urban development. A few
<br /> roads can offset the limited ability of the soil to support areas are used for irrigated crops. This unit may
<br /> ' a load. Houses, roads, and streets should be provide wetland functions and values. These should be
<br /> constructed above expected flood levels. considered in plans for enhancement of wildlife habitat
<br /> This map unit is in capability units Ills-8 (MLRA-17), or land use conversion.
<br /> irrigated, and IVs-8 (MLRA-17), nonirrigated. It is in Where the Jacktone soil Is used for urban
<br /> vegetative soil group G. development, the main limitations are the high shrink-
<br /> swell potential, the slow permeability, depth to the
<br /> 181—Jacktone-Urban land complex, 0 to 2 percent hardpan, and low strength. The rare flooding is a
<br /> ' slopes. This nearly level map unit is in basins. hazard. Properly designing foundations and footings
<br /> Elevation is 10 to 40 feet, The average annual and diverting runoff away from buildings help to prevent
<br /> precipitation is about 14 inches, the average annual air the structural damage caused by shrinking and swelling.
<br /> temperature is about 60 degrees F, and the average On sites for septic tank absorption fields, the slow
<br /> ' frost-free period is about 270 days. permeability can be overcome by increasing the size of
<br /> This unit is 50 percent Jacktone clay and 35 percent the absorption field. Ripping the hardpan improves
<br /> Urban land. The components of this unit occur as areas permeability and thus also improves the suitability of the
<br /> so intricately intermingled that it was not practical to soil for septic tank absorption fields. Properly designing
<br /> map them separately at the scale used. buildings and roads can offset the limited ability of the
<br /> Included in this unit are small areas of Hollenbeck soil to support a load. Houses, roads, and streets
<br /> and Stockton soils in landscape positions similar to should be constructed above expected flood levels.
<br /> ' those of the Jacktone soil. Also included, on the slightly The Jacktone soil is suited to irrigated row, field,
<br /> higher parts of the landscape, are small areas of orchard, and vineyard crops_ The main limitations are
<br /> Jacktone soils that have moderately coarse textured or the slow permeability and depth to the hardpan.
<br /> ' moderately fine textured overwash. Included areas Because of the restricted permeability, water
<br /> make up about 15 percent of the total acreage. applications should be regulated so that the water does
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