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San Joaquin County, California 91
<br /> main limitation is low rainfall during the growing season. 201—Nord loam, 0 to 2 percent slopes. This very
<br /> General management considerations include the hazard deep, well drained, nearly level soil is on alluvial fans. It
<br /> of erosion. Because the amount of precipitation is not formed in alluvium derived from mixed rock sources.
<br /> sufficient for annual cropping, the best suited cropping Elevation is 50 to 70 feet. The average annual
<br /> system is one that includes small grain and summer precipitation is about 11 inches, the average annual air
<br /> fallow. All tillage should be on the contour or across the temperature is about 60 degrees F, and the average
<br /> slope. Limiting tillage during seedbed preparation and frost-free period is about 270 days.
<br /> during the application of weed-control measures helps Typically, the surface layer is brown loam about 25
<br /> to control runoff and erosion. Leaving crop residue on inches thick. The underlying material to a depth of 60
<br /> ` or near the surface helps to conserve moisture, inches is brown, yellowish brown, and pale brown loam
<br /> maintain tilth, and control erosion. and light yellowish brown fine sandy loam. In some
<br /> This unit is suited to irrigated orchard and vineyard areas the surface layer is silt loam.
<br /> crops. The main limitations are the very slow Included in this unit are small areas of Delhi and
<br /> permeability and the depth to a claypan, a dense Honcut soils on the slightly higher parts of the
<br /> subsoil, and weakly cemented sediments. General landscape and Merritt soils in the slightly lower
<br /> ` management considerations include the hazard of positions. Also included, in landscape positions similar
<br /> erosion. Because of the restricted permeability in the to those of the Nord soil, are small areas of moderately
<br /> Comets soil, water applications should be regulated so coarse textured soils that have a slightly brittle
<br /> that the water does not stand on the surface and substratum below a depth of 40 inches and soils that
<br /> damage the crops. The dense subsoil and weakly are gravelly throughout. Included areas make up about
<br /> cemented sediments limit the suitability for deep-rooted 15 percent of the total acreage.
<br /> crops. Where feasible, deep ripping of these restrictive Permeability is moderate in the Nord soil. Available
<br /> layers improves the suitability. A tillage pan forms easily water capacity is high. The effective rooting depth is 60
<br /> if these soils are tilled when wet. Chiseling or subsoiling inches or more. Runoff is slow, and the hazard of water
<br /> breaks up the pan. All tillage should be on the contour erosion is slight. The rate of water intake in irrigated
<br /> .. or across the slope. If the soils are plowed in fall, runoff areas is 1.5 inches per hour. The hazard of soil blowing
<br /> and erosion can be controlled by applying fertilizer and is slight. The soil is subject to rare flooding, which
<br /> seeding a cover crop. Sprinkler and drip irrigation occurs during years of abnormally high precipitation.
<br /> systems are suitable. They permit an even, controlled Most areas are used for irrigated crops, orchards, or
<br /> application of water, help to prevent excessive runoff, vineyards. This unit may provide wetland functions and
<br /> and minimize the risk of erosion. Returning crop residue values. These should be considered in plans for
<br /> to the soils or regularly adding other organic material enhancement of wildlife habitat or land use conversion.
<br /> improves fertility, minimizes crusting, and maintains the This unit is well suited to irrigated row, field, orchard,
<br /> rate of water intake. and vineyard crops. It has few limitations. Furrow,
<br /> If this unit is used for homesite development, the border, and sprinkler irrigation systems are suitable. A
<br /> main limitations are depth to the claypan or dense tillage pan forms easily if the soil is tilled when wet.
<br /> ` subsoil, the high shrink-swell potential, the very slow Chiseling or subsoiling breaks up the pan. Maintaining
<br /> permeability, and low strength. General management crop residue on or near the surface helps to prevent
<br /> considerations include the hazard of erosion. The cuts excessive runoff and soil blowing and helps to maintain
<br /> .. needed to provide essentially level building sites can the rate of water intake and the organic matter content.
<br /> expose the claypan or dense subsoil. Properly This map unit is in capability class I (MLRA-17),
<br /> designing foundations and footings and diverting runoff irrigated, and capability unit IVc-1 (MLRA-17),
<br /> away from buildings help to prevent the structural nonirrigated. It is in vegetative soil group A.
<br /> damage caused by shrinking and swelling. On sites for
<br /> septic tank absorption fields, the very slow permeability 202—Pardee gravelly loam, 0 to 3 percent slopes.
<br /> can be overcome by increasing the size of the This shallow, well drained, nearly level and gently
<br /> absorption field. Properly designing buildings and roads sloping soil is on high terrace remnants. It formed in
<br /> can offset the limited ability of the soils to support a gravelly and cobbly alluvium derived from mixed
<br /> load. Excavation for roads and buildings increases the sources and is underlain by andesitic, tuffaceous
<br /> ■ hazard of erosion. conglomerate. Slopes are plane or convex, and the
<br /> This map unit is in capability unit IVe-3 (MLRA-17), landscape is characterized by hummocky microrelief.
<br /> irrigated and nonirrigated. The Montpellier soil is in Gravel and cobbles cover 3 to 50 percent of the surface
<br /> .. vegetative soil group A, and the Cometa soil is in in small concave areas and commonly less than 3
<br /> vegetative soil group D. percent of the surface in convex areas. The native
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