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114 Soil Survey
<br /> ' a annual cropping, the best suited cropping system is one a depth of 12 to 20 inches and are in landscape
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<br /> I that includes small grain and summer fallow. positions similar to those of the San Joaquin soil.
<br /> i Maintaining crop residue on or near the surface helps to Included areas make up about 15 percent of the total
<br /> prevent excessive runoff and helps to maintain tilth and acreage.
<br /> the organic matter content. Permeability is very slow in the San Joaquin soil.
<br /> If this unit is used for homesite development, the Available water capacity is very low. The shrink-swell ,
<br /> main limitations are depth to the very slowly permeable potential is high. The effective rooting depth is limited
<br /> claypan and hardpan, the high shrink-swell potential, by the hardpan at a depth of 20 to 40 inches. Roots are,:;'
<br /> and low strength in the claypan. On sites for septic tank restricted to cracks and the faces of peds in the
<br /> absorption fields, the very slow permeability can be claypan, which is at a depth of 10 to 20 inches. Water
<br /> overcome by increasing the size of the absorption field, is briefly perched above the claypan and hardpan after;;`':,
<br /> backfilling the trench with sandy material, and installing periods of heavy rainfall or irrigation. Runoff is slow or,,:
<br /> long absorption lines. Ripping the hardpan improves medium, and the hazard of water erosion is slight or
<br /> permeability and thus also improves the suitability of the moderate. The rate of water intake in irrigated areas is
<br /> soil for septic tank absorption fields. Excavation for 1.5 inches per hour.
<br /> buildings is limited by the hardpan. Properly designing 'Most areas are used for livestock grazing. A few T
<br /> foundations and footings and diverting runoff away from areas are used for irrigated vineyards, irrigated Pasture'-
<br /> buildings help to prevent the structural damage caused or dryiand grain crops. This unit may provide wetland`'`;�*.
<br /> by shrinking and swelling. Properly designing buildings functions and values. These should be considered
<br /> and roads can offset the limited ability of the soil to plans for enhancement of wildlife habitat or land use }F
<br /> Fill support a load. conversion. ,
<br /> This map unit is in capability unit lVs-3 (MLRA-17), Where this unit is used for livestock grazing, generally
<br /> irrigated and nonirrigated. It is in vegetative soil group management considerations include saturated soil
<br /> D. conditions in concave areas following rainy periods arid'.
<br /> the hazard of erosion. The characteristic plant e
<br /> 237—San Joaquin sandy loam, 2 to 5 percent community is mainly soft chess, ripgut brome, foxtail; -:u;
<br /> slopes. This moderately well drained, undulating soil is fescue, and filaree. Grazing should be delayed until the
<br /> on dissected terraces. It is moderately deep to a soil is firm enough to withstand trampling by livestock; °
<br /> hardpan. It formed in alluvium derived from granitic rock and the more desirable forage plants have had an
<br /> sources. The native vegetation is mainly annual opportunity to set seed. Grazing should be controlled,so
<br /> grasses, (orbs, and scattered California white oak. that desirable vegetation, such as soft chess, is f
<br /> Slopes occur as a complex of plane and convex side maintained and enough vegetation is left standing to
<br /> slopes and concave drainageways. Elevation is 20 to protect the soil from erosion.
<br /> 150 feet. The average annual precipitation is about 16 This unit is suited to irrigated vineyard crops The :: 1
<br /> inches, the average annual air temperature is about 61 main limitations are depth to the very slowly per meaf?I" '
<br /> degrees F, and the average frost-free period is about claypan and hardpan and the very low available water,'
<br /> 275 days. capacity. General management considerations include'
<br /> Typically, the surface layer is brown sandy loam the hazard of erosion. Because of the restricted
<br /> i about 10 inches thick. The upper part of the subsoil is a permeability, water applications should be regulated'g,
<br /> claypan of brown clay about 10 inches thick. The lower that the water does not stand on the surface andF]
<br /> part to a depth of 60 inches is a brown and light brown, damage the crops. The hardpan limits the suitability for
<br /> indurated hardpan. In some areas the surface layer is deep-rooted crops. Where feasible, deep ripping of thi
<br /> fine sandy loam. restrictive layer can help to overcome this limitation._.A-
<br /> 'f h soil i filled when
<br /> wet.
<br /> Included in this unit are small areas of Bruella and tillage an forms Basil i the so s t
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<br /> Rocklin soils on the slightly higher terraces, Jahant soils Chiseling or subsoiling breaks up the pan. Because th,
<br /> in landscape positions similar to those of the San soil is droughty, applications of irrigation water shoultl.
<br /> Joaquin soil, Madera soils in the slightly lower positions, be light and frequent. Sprinkler and drip irrigation `=
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<br /> and San Joaquin soils that have slopes of 0 to 2 or 8 to systems are suitable. They permit an even, controlled
<br /> 15 percent. The areas where slopes are 0 to 2 percent application of water, help to prevent excessive runoff,`
<br /> are on toe slopes, and the areas where slopes are 8 to and minimize the risk of erosion. All tillage should be';:
<br /> 15P ercent are on narrow embankments. Also included the contour or across the slope. if the soil is plowed
<br /> are small areas of Redding soils that have slopes of 2 fall, runoff and erosion can be controlled by applying_,
<br /> to 8 percent and are on the slightly higher terraces and fertilizer and seeding a cover crop. Returning crop
<br /> moderately coarse textured soils that have a hardpan at residue to the soil or regularly adding other organic
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