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<br />San Joaquin County, California
<br />some areas the surface layer is loam.
<br />r Included in this unit are small areas of Rocklin, San
<br />Joaquin, Jahant, and Tokay soils in the slightly lower
<br />landscape positions. Also included are small areas of
<br />Bruella soils that do not have a hard substratum.
<br />` Included areas make up about 15 percent of the total
<br />acreage.
<br />Permeability is moderately slow in the upper part of
<br />the Bruella soil and slow in the hard substratum.
<br />Available water capacity is moderate. The effective
<br />rooting depth is 60 inches, but roots are restricted by
<br />the hard substratum at a depth of 40 to 60 inches.
<br />Depth to the water table is more than 6 feet, but water
<br />may be very briefly perched above the hard substratum
<br />after periods of heavy rainfall or irrigation. Runoff is
<br />slow, and the hazard of water erosion is slight. The rate
<br />of water intake in irrigated areas is 1.5 inches per hour.
<br />Most areas are used for irrigated crops, orchards, or
<br />vineyards. A few areas are used for homesite
<br />development. This unit may provide wetland functions
<br />and values. These should be considered in plans for
<br />enhancement of wildlife habitat or land use conversion.
<br />This unit is suited to irrigated row, field, orchard, and
<br />vineyard crops. The main limitations are the slow
<br />permeability and depth to the hard substratum. Because
<br />of the restricted permeability, water applications should
<br />be regulated so that the water does not stand on the
<br />surface and damage the crops. The hard substratum
<br />.. limits the suitability for deep-rooted crops. Where
<br />feasible, deep ripping of this restrictive layer can help to
<br />overcome this limitation. Furrow, border, and sprinkler
<br />.irrigation systems are suitable. Returning crop residue
<br />to the soil or regularly adding other organic material
<br />improves fertility, minimizes crusting, and maintains the
<br />rate of water intake.
<br />If this unit is used for homesite development, the
<br />main limitations are the slow permeability and depth to
<br />the hard substratum. On sites for septic tank absorption
<br />rfields, the slow permeability can be overcome by
<br />increasing the size of the absorption field, backfilling the
<br />trench with sandy material, and installing long
<br />absorption lines. Ripping the hard substratum improves
<br />Permeability and thus also improves the suitability of the
<br />soil for septic tank absorption fields.
<br />This map unit is in capability units IIs -3 (MLRA-17),
<br />"'Irrigated, and IVs -3 (MLRA-17), nonirrigated. It is in
<br />vegetative soil group A.
<br />4- 113—Calla clay loam, 2 to 8 percent slopes. This
<br />very deep, well drained, gently sloping and moderately
<br />loping soil is on uplifted, dissected terraces. It formed
<br />n alluvium derived from mixed rock sources. The
<br />vegetation in areas that have not been cultivated is
<br />mainly annual grasses and forbs. Elevation is 300 to
<br />33
<br />500 feet. The average annual precipitation is 9 to 13
<br />inches, the average annual air temperature is about 61
<br />degrees F, and the average frost -free period is about
<br />270 days.
<br />Typically, the surface layer and the upper part of the
<br />subsoil are light brownish gray clay loam about 11
<br />inches thick. The next part of the subsoil is light gray,
<br />grayish brown, and light brownish gray clay loam about
<br />18 inches thick. The lower part to a depth of 60 inches
<br />is whae and light gray clay loam. The soil is calcareous
<br />throughout. In some areas the surface layer is loam.
<br />Included in this unit are small areas of Carbona and
<br />Pleito soils in the slightly lower landscape positions.
<br />Also included, on the slightly higher parts of the
<br />landscape, are small areas of Calla soils that have
<br />slopes of 8 to 15 percent. Included areas make up
<br />about 15 percent of the total acreage.
<br />Permeability is moderately slow in the Calla soil.
<br />Available water capacity is very high. The effective
<br />rooting depth is 60 inches or more. Runoff is medium,
<br />and the hazard of water erosion is moderate. The rate
<br />of water intake in irrigated areas is 0.5 inch per hour.
<br />This unit is used for livestock grazing or dryland grain
<br />crops. It can be used for irrigated crops if irrigation
<br />water is available.
<br />Where this unit is used for livestock grazing, general
<br />management considerations include the clay loam
<br />surface layer. The characteristic plant community is
<br />mainly soft chess, red brome, wild oat, and filaree.
<br />Trampling of the clay loam surface layer by livestock
<br />when the soil is too wet reduces productivity and
<br />increases the runoff rate.
<br />Where this unit is used for dryland grain crops, the
<br />main limitation is low rainfall during the growing season.
<br />General management considerations include the hazard
<br />of erosion. Because the amount of precipitation is not
<br />sufficient for annual cropping, the best suited cropping
<br />system is one that includes small grain and summer
<br />fallow. All tillage should be on the contour or across the
<br />slope. Leaving crop residue on or near the surface
<br />helps to conserve moisture, maintain tilth, and control
<br />erosion.
<br />Few limitations affect the use of this unit for irrigated
<br />row, field, and orchard crops. General management
<br />considerations include the hazard of erosion. Sprinkler
<br />and drip irrigation systems are suitable. They permit an
<br />even, controlled application of water, help to prevent
<br />excessive runoff, and minimize the risk of erosion. All
<br />tillage should be on the contour or across the slope.
<br />Returning crop residue to the soil or regularly adding
<br />other organic material improves fertility, minimizes
<br />crusting, and increases the rate of water intake.
<br />This map unit is in capability unit IVe-1 (MLRA-17),
<br />nonirrigated. It is in vegetative soil group A.
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