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<br />30
<br />RECE~h~'Djey
<br />APR 19 1999
<br />capacity. Deferred grazing, cross fencing, and stockwater
<br />developments help to prevent range deterioration and
<br />promote the growth of more desirable plants.
<br />If this soil is used as range, it has limited potential for
<br />wildlife habitat because of low vegetative production. In
<br />nonirrigated areas, the best use is for such wildlife as
<br />jackrabbit, cottontail, and coyote. Il this sparsely
<br />vegetated soil is used for wildlife habitat, proper livestock
<br />grazing management is necessary. If this soil is irrigated,
<br />crop residue from oats and barley can provide food for
<br />ring-necked pheasant and waterfowl.
<br />This soil is suited to homesite development. The main
<br />limitations are large amounts of gravel and cobblestones.
<br />This soil is a good source of sand, gravel, and roadfill
<br />material. Caving of cutbanks is a hazard if areas of this
<br />soil are excavated. In some places, septic tank systems
<br />and trench-type sanitary landfills can cause ground water
<br />contamination because of the very rapid permeability of
<br />the substratum.
<br />This soil is in capability subclass IVs, irrigated, and
<br />Vlls, nonirrigated. It is in the Mountain Outwash range
<br />site.
<br />21-Des Moines gravelly clay loam, dry, 0 to 2
<br />percent slopes. This deep, well drained soil is on
<br />alluvial valley floors and fans. Elevation is 7,600 to 8,000
<br />feet. The soil formed in alluvium derived from igneous
<br />rock. The average annual precipitation is about 12
<br />inches; the average annual air temperature is about 41
<br />degrees F; and the average frost-free period is about 95
<br />days.
<br />Included in mapping are small areas of Platoro loam,
<br />Derrick very gravelly loam, and San Arcacio sandy loam,
<br />all having slopes of 0 to f percent.
<br />Typically, the surtace layer of this Des Moines soil is
<br />gray gravelly clay loam about 6 inches thick. The subsoil,
<br />about 11 inches thick, is gray very gravelly silty clay
<br />loam in the upper part and gray very gravelly sandy clay
<br />loam in the lower part. The substratum to a depth of 60
<br />inches or more is light brownish gray very cobbly sandy
<br />clay loam that grades to light brownish gray extremely
<br />cobbly sandy clay loam.
<br />Permeability is moderately slow. Effective rooting
<br />depth is about 60 inches. Available water capacity is
<br />moderate. Surface runoff is slow, and the hazard of
<br />erosion is slight.
<br />This soil is used as native range. Some small areas
<br />are used for irrigated alfalfa. Border and furrow methods
<br />of irrigation are suited to this soil. Land leveling and
<br />adjusted lengths of run are needed for proper water
<br />distribution.
<br />The potential natural vegetation on this Des Moines
<br />soil is dominated by blue grama, Indian ricegrass,
<br />western wheatgrass, needleandthread, winterfat, and
<br />fourwing saltbush. I( the range deteriorates, the
<br />proportion of Indian ricegrass, needleandthread, and
<br />western wheatgrass decreases, and that of blue grama,
<br />threeawn, snakeweed, and rabbitbrush increases.
<br />Undesirable weeds invade and be¢bre~moDk~tt9~19P109Y
<br />as the range condition declines.
<br />Seeding rangeland is difficult on this soil because of
<br />the low rainfall and moderate available water capacity.
<br />Deferred grazing, cross fencing, and stockwater
<br />developments help prevent range deterioration and
<br />promote the growth of more desirable plants.
<br />If not irrigated, this soil has limited potential for wildlife
<br />habitat because of low vegetative production. This soil
<br />supports such wildlife as jackrabbit, cottontail, and
<br />coyote, as well as various rodents. If this soil is used for
<br />wildlife habitat and range, proper livestock grazing
<br />management is necessary. In irrigated areas, crop
<br />residue from alfalfa and small grains provides food for
<br />pheasant and waterfowl.
<br />This soil is suited to homesite development. The main
<br />limitations are the large number of cobblestones
<br />throughout the profile and the moderate shrink-swell
<br />potential. Use of this soil for local roads and streets is
<br />somewhat limited by frost action, cobblestones, and
<br />shrink-swell potential. If this soil is used for septic tank
<br />absorption fields, the limitation of moderately slow
<br />permeability can be overcome by placing the absorption
<br />field below the subsoil and by increasing the size of the
<br />absorption field.
<br />This soil is in capability subclasses IVs, irrigated, and
<br />Vlle, nonirrigated. It is in the Mountain Outwash range
<br />site.
<br />22-Dune land. Dune land is in the southeastern
<br />corner of the survey area. Most of the acreage of the
<br />Great Sand Dunes National Monument is of this land
<br />type.
<br />The dunes, which are made up of constantly shifting
<br />sand, may be as high as 600 feet. This sand has been
<br />deposited by the wind, presumably by southwesterly
<br />winds that blow across the San Luis Valley. Surface
<br />runoff is very slow, permeability is very rapid, and the
<br />available water capacity is very low. The hazard of soil
<br />blowing is high.
<br />There is little or no vegetation on the dunes; thus,
<br />wildlife is for the most part transitory. Some weeds,
<br />lemon scurfpea, prairie sandreed, and blowoutgrass grow
<br />in low depressions or on the peripheral areas. Major
<br />uses of the dunes are for recreation and sightseeing.
<br />This miscellaneous area is in capability class VIII.
<br />23-Dunul very gravelly sandy loam. This deep,
<br />nearly level, somewhat excessively drained soil is on
<br />fans and terraces on alluvial valley floors. Elevation is
<br />7,600 to 8,000 feet. The soil formed in very gravelly
<br />alluvium. The average annual precipitation is about 7
<br />inches; the average annual air temperature is about 41
<br />degrees F; and the frost-free period is about 95 days.
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