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`San Joaquin County, California 115
<br /> :k_: material improves fertility, minimizes crusting, and San Joaquin soils that have slopes of 2 to 5 percent
<br /> xpmaintains the rate of water intake. and are on the slightly higher parts of the landscape.
<br /> This unit is suited to irrigated pasture. The main Also included are areas that have as much as 20
<br /> Iifnitation is the very low available water capacity. inches of overburden and areas where most of the soil
<br /> %eheraI management considerations include the hazard horizons have been removed or altered as a result of
<br /> of;#erosion. Because the soil is droughty, applications of land leveling. Included areas make up about 15 percent
<br /> �`jragation water should be light and frequent. The water of the total acreage.
<br /> 3,an be applied by sprinkler and border methods. Permeability is very slow in the San Joaquin soil.
<br /> edbed preparation should be on the contour or Available water capacity is low. The shrink-swell
<br /> ecross the slope where practical. Proper stocking rates, potential is high. The effective rooting depth is limited
<br /> ` jpasture rotation, and restricted grazing during wet by the hardpan at a depth of 20 to 40 inches. Roots are
<br /> bejods help to keep the pasture in good condition and restricted to cracks and the faces of peds in the
<br /> protect the soil from erosion. claypan, which is at a depth of 10 to 20 inches. Water
<br /> &'Where this unit is used for dryland grain crops, the is briefly perched above the claypan and hardpan after
<br /> ,mam;limi#ation is low rainfall during the growing season. periods of heavy rainfall or irrigation. Runoff is ponded
<br /> .General management considerations include the hazard in the small vernal pools, is very slow or ponded in the
<br /> bf•erosion. Because the amount of precipitation is not leveled areas, and is slow on the convex slopes. The
<br /> ` sufficient for annual cropping, the best suited cropping hazard of water erosion is slight. The rate of water
<br /> pp� g g.
<br /> s stem is one that includes small grain and summer intake in irrigated areas is 1.0 inch per hour.
<br /> fallow.. All tillage should be on the contour or across the Most areas are used for livestock grazing or for
<br /> 4
<br /> slope_Leaving crop residue on or near the surface irrigated pasture, irrigated crops, or vineyards. A few
<br /> :4 helps-;to conserve moisture, maintain filth, and control areas are used for dryland grain crops or for homesite
<br /> .'erosion. development. This unit may provide wetland functions
<br /> This map unit is in capability unit IVe-3 (MLRA-17), and values. These should be considered in plans for
<br /> .:1rbgafed and nonirrigated. It is in vegetative soil group enhancement of wildlife habitat or land use conversion.
<br /> yDf�Y' Where this unit is used for livestock grazing, general
<br /> management considerations include saturated soil
<br /> X238' San Joaquin loam, 0 to 2 percent slopes. conditions in concave areas following rainy periods. The
<br /> ells 1,tnode rate Iy well drained, nearly level soil is on low characteristic plant community is mainly soft chess,
<br /> to races. It is moderately deep to a hardpan. It formed ripgut brome, foxtail fescue, and filaree. Grazing should
<br /> 'dri ll avium derived from granitic rock sources. The be delayed until the soil is firm enough to withstand
<br /> najiv,vegetation is mainly annual grasses, forbs, and trampling by livestock and the more desirable forage
<br /> Scattered California white oak. The landscape is plants have had an opportunity to set seed.
<br /> caracterized by a complex of gently sloping hummocks This unit is suited to irrigated pasture. The main
<br /> and depressions, minor drainageways, and areas that limitations are the complex slopes and the low available
<br /> sateen leveled. Meandering drainageways and water capacity. Leveling helps to ensure a uniform
<br /> etaed'depressions fill with water to form vernal pools application of water. Because the soil is droughty, the
<br /> duing;It
<br /> he winter in many areas. Elevation is 20 to 100 applications should be light and frequent. The water can
<br /> feef The, verage annual precipitation is about 16 be applied by sprinkler and border methods. Proper
<br /> iitcthes,:the average annual air temperature is about 61 stocking rates, pasture rotation, and restricted grazing
<br /> degrees F, and the average frost-free period is about during wet periods help to keep the pasture in good
<br /> .:x275 days. condition and protect the soil from compaction.
<br /> typically, the surface layer and the upper part of the This unit is suited to irrigated row, field, and vineyard
<br /> ° �isoif are brown loam about 16 inches thick. The next crops. The main limitations are the complex slopes,
<br /> K}Filart of the subsoil is a claypan of brown clay about 10 depth to the very slowly permeable claypan and
<br /> 'anChes-thick. The lower part to a depth of 60 inches is a hardpan, and the low available water capacity. Leveling
<br /> ,brOwn light brown, and strong brown, indurated helps to ensure a uniform application of water. Because
<br /> hardpe ;,In some areas the surface layer is fine sand of the restricted permeability, the applications should be
<br /> loarrs�, Y Y p Y
<br /> regulated so that the water does not stand on the
<br /> Inehuded in this unit are small areas of Hollenbeck surface and damage the crops. The hardpan limits the '
<br /> 'end 4alisOils in the slightly lower landscape positions, suitability for deep-rooted crops. Where feasible, deep
<br /> mpderately coarse textured soils that have a hardpan at ripping of this restrictive layer can help to overcome this
<br /> epth�b_f 12 to 20 inches and are in landscape limitation. A tillage pan forms easily if the soil is tilled
<br /> p°5rtionssimilar to those of the San Joaquin soil, and when wet. Chiseling or subsoiling breaks up the pan.
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