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<br />La Plata County Area, Colorado
<br />Included in this unit are about 10 percent Pulpit loam
<br />and 10 percent shallow soils that are similar to the Pulpit
<br />soils.
<br />The Lazear soil is shallow and well drained. It formed
<br />in residual material derived from sandstone and shale.
<br />Typically, the upper part of the surface layer is brown
<br />very stony loam about 5 inches thick and the lower part
<br />is light yellowish brown loam about 3 inches thick. The
<br />underlying material is very pale brown loam about 7
<br />inches thick. Sandstone is at a depth of 15 inches.
<br />Depth to sandstone ranges from 10 to 20 inches.
<br />Permeability of this Lazear soil is moderate. Effective
<br />rooting depth is 10 to 20 inches because of the
<br />presence of hard bedrock. Available water capacity is
<br />very low. Runoff is medium, and the hazard of erosion is
<br />moderate.
<br />Rock outcrop consists of nearly barren exposures of
<br />sandstone. It is typically on mesa rims and includes
<br />many vertical cliffs.
<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, Indian ricegrass, needleandthread,
<br />muttongrass, Mormon-tea, junegrass, pinyon, Rocky
<br />Mountain juniper, and big sagebrush. Proper grazing use
<br />as part of a planned grazing system helps to maintain
<br />the quality and quantity of the rangeland vegetation.
<br />Seeding and deferring grazing facilitate revegetation of
<br />areas depleted by heavy grazing and other disturbances.
<br />Seeding should be done by hand broadcasting or aerial
<br />methods. Developing livestock watering facilities,
<br />fencing, and deferring grazing improve the distribution of
<br />grazing and help to maintain the condition of the
<br />rangeland.
<br />The Lazear soil is suited to the production of pinyon
<br />and juniper. Woodland products such as firewood,
<br />fenceposts, Christmas trees, and pinyon nuts can be
<br />obtained from this unit. The unit is capable of producing
<br />about 14 cords of firewood per acre in a stand of trees
<br />that average 5 inches in diameter at a height of 1 foot, if
<br />all limbs larger than 2 inches in diameter are used.
<br />The main limitations for the production of pinyon and
<br />juniper are the shallow depth to bedrock, low available
<br />water capacity, steepness of slope, stoniness, and
<br />moderate hazard of erosion. Limiting soil disturbance
<br />when harvesting trees helps to minimize erosion.
<br />Seeding to adapted grasses may be needed in some
<br />areas after harvesting. Low precipitation and the
<br />presence of brushy plants may influence seedling
<br />survival. Areas can be maintained in pinyon and juniper
<br />by selective cutting, leaving small trees and a few of the
<br />larger seed producing trees, and controlling livestock
<br />grazing so that seedlings can become established.
<br />Wildlife such as mule deer, coyote, cottontail, squirrel,
<br />and mourning dove use this unit. They obtain food from
<br />areas of grasses and shrubs and from nearby areas of
<br />cropland. The wooded areas provide shelter and nesting
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<br />areas. Suitable management for wildlife should include
<br />providing protection from wildfire and overgrazing and
<br />maintaining areas in pinyon and juniper.
<br />Steepness of slope and shallow depth to bedrock are
<br />the main limitations for homesite and urban development
<br />on the Lazear soil. These limitations should also be
<br />considered when planning septic tank absorption fields
<br />or sewage lagoons. The use of an alternate system
<br />should be considered.
<br />This map unit is in capability subclass Vlls,
<br />nonirrigated.
<br />43-Leadville very stony sandy loam, 15 to 55
<br />percent slopes. This deep, well drained soil is on
<br />mountainsides. It formed in glacial till and alluvial and
<br />colluvial material. Elevation is 8,000 to 10,000 feet. The
<br />average annual precipitation is 18 to 22 inches. The
<br />average annual air temperature is 38 to 43 degrees F,
<br />and the average frost-free period is 60 to 80 days.
<br />Typically, the surface is covered with a mat of pine
<br />needles and leaves about 2 inches thick. The surface
<br />layer is brown very stony sandy loam about 2 inches
<br />thick. The next layer is pinkish gray very stony sandy
<br />loam about 17 inches thick. The upper part of the
<br />subsoil is mixed pinkish gray and reddish brown very
<br />stony sandy clay loam about 4 inches thick, and the
<br />lower part is reddish brown very stony sandy clay loam
<br />about 30 inches thick. The substratum is reddish brown
<br />very stony sandy loam that extends to a depth of 60
<br />inches or more.
<br />Included in this unit are about 15 percent Horsethief
<br />stony fine sandy loam, 15 percent Uinta loam, and 15
<br />percent soils that have less gravel than does this
<br />Leadville soil.
<br />Permeability of this Leadville soil is moderate. Effective
<br />rooting depth is 60 inches or more. Available water
<br />capacity is low. Runoff is medium, and the hazard of
<br />erosion is slight.
<br />This unit is used for timber production and wildlife
<br />habitat and for limited livestock grazing.
<br />This unit is suited to the production of Engelmann
<br />spruce. On the basis of a site index of 60, it is capable
<br />of producing about 5,000 cubic feet or 27,500 board feet
<br />(International rule) of marketable timber per acre from a
<br />fully stocked, even-aged stand of trees 100 years old.
<br />The unit is also suited to the production of Douglas-fir,
<br />white fir, and aspen.
<br />The main concerns for the management of timber are
<br />controlling cutting and controlling erosion along roads
<br />and in other areas where the plant cover has been
<br />removed. Harvesting may be restricted during periods
<br />when snow accumulates to a great depth, during
<br />snowmelt, and during periods of high rainfall.
<br />Reforestation should be carefully managed to reduce
<br />competition from undesirable understory plants. Careful
<br />consideration of road systems and harvesting methods is
<br />needed to minimize erosion.
<br />May 1994
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