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Lane County Area, Oregon
<br />Included in this unit are small areas of Chehalis,
<br />Salem, McBee, and Malabon soils. Included areas make
<br />up about 15 percent of the total acreage.
<br />The relatively undisturbed Chapman soil is deep and
<br />well drained. It formed in recent mixed alluvium.
<br />Typically, the upper part of the surface layer is dark
<br />brown loam about 8 inches thick, and the lower part is
<br />very dark grayish brown clay loam about 6 inches thick.
<br />The subsoil is dark brown and dark yellowish brown
<br />loam about 28 inches thick. The upper part of the
<br />substratum is brown gravelly sandy loam about 8 inches
<br />thick, and the lower part to a depth of 60 inches or more
<br />is dark brown very gravelly sandy loam. Strata of coarse
<br />sand and gravel are common below a depth of 40
<br />inches.
<br />Permeability of this Chapman soil is moderate.
<br />Available water capacity is about 8 to 12 inches. Water
<br />supplying capacity is 19 to 24 inches. Effective rooting
<br />depth is 60 inches or more. Runoff is slow, and the
<br />hazard of water erosion is slight. This soil is subject to
<br />rare periods of flooding.
<br />The disturbed Chapman soil has been covered by as
<br />much as 40 inches of fill material or has had as much as
<br />30 inches of the original profile removed by cutting or
<br />grading. The fill material is commonly from adjacent
<br />areas of Chapman, Chehalis, Salem, McBee, or Malabon
<br />soils that have been cut or graded. The characteristics of
<br />the disturbed areas are highly variable.
<br />Urban land consists of areas where the soils are
<br />largely covered by concrete, asphalt, buildings, or other
<br />impervious surfaces that obscure or alter the soils so
<br />that identification is not feasible.
<br />This unit is used mainly for urban development. It is
<br />also used for yards and as open areas around and
<br />between buildings.
<br />If this unit is used for urban development, the main
<br />limitation is the hazard of rare flooding from prolonged,
<br />heavy rainfall and snowmelt that fill the large reservoirs
<br />upstream and override the effect of the dams.
<br />In summer, irrigation is required for lawn grasses,
<br />shrubs, vines, shade trees, and ornamental-trees. Plants
<br />that tolerate droughtiness should be selected if irrigation
<br />is not provided.
<br />This map unit is not assigned a capability
<br />classification.
<br />26-Chehalis silty clay loam, occasionally flooded.
<br />This deep, well drained soil is on flood plains. It formed
<br />in recent mixed alluvium. Slope is 0 to 3 percent. Areas
<br />are elongated in shape and are 3 to 100 acres or more
<br />in size. The vegetation in areas not cultivated is mainly
<br />Douglas-fir, bigleaf maple, Oregon white oak, black
<br />cottonwood, shrubs, and grasses. Elevation is 290 to
<br />1,000 feet. The average annual precipitation is 40 to 60
<br />inches, the average annual air temperature is 52 to 54
<br />degrees F, and the average frost-free period is 165 to
<br />.210 days.
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<br />Typically, the surface layer is dark brown silty clay
<br />loam about 13 inches thick. The subsoil is dark brown
<br />and brown silty clay loam about 42 inches thick. The
<br />substratum to a depth of 70 inches is brown silt loam.
<br />Included in this unit are small areas of Chapman,
<br />Cloquato, McBee, and Newberg soils. Included areas
<br />make up about 15 percent of the total acreage.
<br />Permeability of this Chehalis soil is moderate.
<br />Available water capacity is about 11 to 13 inches. Water
<br />supplying capacity is 20 to 26 inches. Effective rooting
<br />depth is more than 60 inches. Runoff is slow, and the
<br />hazard of water erosion is slight. This soil is occasionally
<br />flooded for brief periods from November to March.
<br />Most areas of this unit are used for row crops, small
<br />grain, hay, pasture, and orchards. A few areas are used
<br />as homesites and for recreation.
<br />This unit is suited to all climatically adapted crops. In
<br />summer, irrigation is required for maximum production of
<br />most crops. Sprinkler irrigation is a suitable method of
<br />applying water. Use of this method permits the even,
<br />controlled application of water, reduces runoff, and
<br />minimizes the risk of erosion.
<br />In winter and spring, cover crops help to protect the
<br />soil from erosion by flooding. Returning alt crop residue
<br />to the soil and using a cropping system that includes
<br />grasses, legumes, or grass-legume mixtures help to
<br />maintain fertility and filth. Grain and grasses respond to
<br />nitrogen; legumes respond to phosphorus, boron, sulfur,
<br />and lime; and vegetables and berries respond to
<br />nitrogen, phosphorus, and potassium.
<br />This unit is suited to hay and pasture. Proper stocking
<br />rates, pasture rotation, and restricted grazing during wet
<br />periods help to keep the pasture in good condition and
<br />to protect the soil from erosion and compaction.
<br />This unit is suited to recreational development
<br />because of its location near streams. It is limited mainly
<br />by the hazard of flooding and the clay content of the
<br />surface layer.
<br />If this unit is used for homesite development, the main
<br />limitations are the hazard of flooding and the moderate
<br />shrink-swell potential. The risk of flooding has been
<br />reduced in some areas by the construction of dams and
<br />reservoirs on large streams. If buildings are constructed
<br />on this unit, property designing foundations and footings
<br />and diverting _ runoff away from buildings help to prevent
<br />structural damage as a result of shrinking and swelling.
<br />This unit is in capability subclass Ilw.
<br />27-Chehalis-Urban land complex. This map unit is
<br />on flood plains. Slope is 0 to 3 percent. Areas are
<br />elongated in shape and are 2 to 100 acres or more in
<br />size. The native vegetation is mainly Douglas-fir, bigleaf
<br />maple, Oregon white oak, black cottonwood, shrubs, and
<br />grasses. Elevation is 300 to 1,000 feet. The average
<br />annual precipitation is 40 to 60 inches, the average
<br />annual air temperature is 52 to 54 degrees F, and the
<br />average frost-free period is 165 to 210 days.
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