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<br />
<br />
<br />La Plata County Area, Colorado
<br />maintaining areas of pinyon and juniper
<br />This unit i uited to homesite and urban development.
<br />The moderate p eability and slope should be
<br />considered when pla g septic tank absorption fields
<br />or sewage lagoons. Abso n fields may need to be
<br />made larger than normal. Sewa agoons can be used
<br />it the limitation of slope can be over e. They should
<br />be sealed to reduce seepage.
<br />This map unit is in capability subclass IVe, it ted
<br />and nonirrrgated. p~~,~'///,~
<br />45-Nehar s~ity sa7fdy9y~am. This deep, well
<br />drained soil is on terraces along major drainageways. It
<br />formed in cobbly and stony glacial oulwash or till. Slope
<br />is 1 to 6 percent. Elevation is 6,000 to 7,000 feet. The
<br />average annual precipitation is 13 to 16 inches. The
<br />average annual air temperature is 45 to 50 degrees F,
<br />and the frost-free period is 110 to 130 days.
<br />Typically, the upper part of the surface layer is light
<br />brown stony sandy loam about 4 inches thick and the
<br />lower part is reddish brown stony loam about 5 inches
<br />thick. The next layer is reddish brown stony clay loam 4
<br />inches thick. The upper part of the subsoil is reddish
<br />brown very cobbly clay loam over stony clay loam about
<br />18 inches thick, and the lower part is yellowish red very
<br />cobbly clay loam about 11 inches thick. The substratum
<br />is light reddish brown extremely stony sandy loam that
<br />extends to a depth of 60 inches or more.
<br />Included in this unit are 20 percent Agua Fria loam
<br />and small areas of Harlan cobbly loam and Sedillo
<br />gravelly loam.
<br />Permeability of this Nehar soil is moderately slow.
<br />Effective rooting depth is 60 inches or more. Available
<br />water capacity is low. Runoff is slow, and the hazard of
<br />erosion is slight.
<br />This unit is used mainly as rangeland and for wildlife
<br />habitat.
<br />The native vegetation on this unit is mainly western
<br />wheatgrass, slender wheatgrass, Indian ricegrass,
<br />junegrass, blue grams, big sagebrush, pinyon, and Rocky
<br />Mountain juniper. Proper grazing use as part of a
<br />planned grazing system helps to maintain the quality and
<br />quantity of the preferred rangeland vegetation. Brush
<br />control, rangeland seeding, and deferment of grazing
<br />facilitate revegetation of areas depleted by heavy grazing
<br />and other disturbances. Developing livestock watering
<br />facilities, fencing, and deferring grazing improve the
<br />distribution of grazing and help to maintain the condition
<br />of the rangeland.
<br />Wildlife such as mule deer, cottontail, squirrel, coyote,
<br />pheasant, mourning dove, and various other species of
<br />bird use this unit. Areas of rangeland and nearby areas
<br />of pinyon and juniper woodland provide shelter and
<br />nesting areas and some food for wildlife. Nearby
<br />cropland areas are sources of Tood. Suitable
<br />management for wildlife should include protecting the
<br />as
<br />unit from overgrazing and wildfire and maintaining
<br />adequate plant cover.
<br />High shrink-swell potential, large stones, and low soil
<br />strength are the main limitations for homesite and urban
<br />development. The foundations of buildings should be
<br />designed to compensate for the high shrink-swell
<br />potential. Roads should be designed to overcome the
<br />limitations of low soil strength and high shrink-swell
<br />potential. Cobbles and stones limit excavations for
<br />basements, utility lines, and roads. The moderately slow
<br />permeability and the presence of cobbles and stones
<br />should be considered when designing septic tank
<br />absorption Tields or sewage lagoons. Absorption fields
<br />can be made larger than normal or installed deeper,
<br />where the soil material is more permeable. Sewage
<br />lagoons can be lined to overcome the limitation of
<br />seepage.
<br />This map unit is in capability subclass Vle,
<br />nonirrigated.
<br />4 Nordicol very stony sandy loam, 6 to 25
<br />pert t slopes. This deep, well drained soil is on
<br />mount 'sides. It formed in colluvium and alluvium
<br />derived om sandstone. Elevation is 7,800 to 10,000
<br />feet. The verage annual precipitation is 20 to 25 inches.
<br />The avers annual air temperature is 38 to 42 degrees
<br />F, and the f st-tree period is 60 to 80 days.
<br />Typically, t surface is covered with a layer of
<br />undecompose needles, leaves, and twigs about 1 inch
<br />thick. The surfs layer is dark grayish brown and brown
<br />very stony sandy oam about 12 inches thick. The next
<br />layer is light brown' h gray very stony sandy loam about
<br />12 inches thick. Th upper part of the subsoil is light
<br />brown and brown ve stony sandy clay loam about 12
<br />inches thick, and the I er part to a depth of 60 inches
<br />or more is brown very s ny sandy clay loam. In some
<br />places the surface layer i very stony loam.
<br />Included in this unit are out 20 percent Anvik loam
<br />and small areas of Goldvale ery stony fine sandy loam,
<br />Fortwingate stony fine sandy am, and Chris very stony
<br />loam.
<br />Permeability of this Nordicol s 'I is moderate. Effective
<br />rooting depth is 60 inches or mor Available water
<br />capacity is moderate. Runoff is slo and the hazard of
<br />erosion is slight.
<br />This unit is used mainly as woodlan and for limited
<br />homesite development. It is also used f wildlife habitat
<br />and limited livestock grazing.
<br />This unit is well suited to the production f Douglas-fir.
<br />On the basis of a site index of 80, the poten'al
<br />production of marketable timber per acre is 5, t0 cubic
<br />feet or 31,200 board feet (International rule) fr m a fully
<br />stocked, even-aged stand of trees 100 years of .Other
<br />trees generally suited to this unit are white fir, as en,
<br />Engelmann spruce, and ponderosa pine.
<br />The main concerns in producing and harvesting 'mbel
<br />are equipment limitations because of the presence f
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