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Rio Blanco County Area, Colorado
<br />soil in the unit is firm and the more desirable forage
<br />plants have achieved sufficient growth to withstand
<br />grazing pressure.
<br />If the range vegetation is seriously deteriorated,
<br />seeding is needed. For successful seeding, prepare a
<br />seedbed and drill in the seed. The plants selected for
<br />seeding should meet the seasonal requirements of
<br />livestock or wildlife, or both.
<br />If this unit is used for homesite development, the main
<br />limitations are the potential for shrinking and swelling
<br />and slow permeability. Structures to divert runoff are
<br />needed if buildings and roads are constructed. Buildings
<br />and roads should be designed to offset the limited ability
<br />of the soil in this unit to support a load. The effects of
<br />shrinking and swelling can be minimized by using proper
<br />engineering designs and by backfilling excavations with
<br />material that has low shrink -swell potential.
<br />This map unit is in capability subclass IVc. It is in Deep
<br />Loam range site.
<br />101—Work loam, 3 to 8 percent slopes. This deep,
<br />well drained soil is on uplands, fans, and terraces. It
<br />formed in eolian and alluvial material. Areas are
<br />elongated and are 20 to 400 acres. The native
<br />vegetation is mainly low shrubs and grasses. Elevation is
<br />6,100 to 7,400 feet. The average annual precipitation is
<br />15 to 18 inches, the average annual air temperature is
<br />39 to 42 degrees F, and the average frost -free period is
<br />80 to 105 days.
<br />Typically, the surface layer is brown loam 10 inches
<br />thick. The upper 5 inches of the subsoil is brown clay
<br />loam, and the lower 10 inches is light brown clay loam.
<br />The next layer is light brown clay loam 5 inches thick.
<br />The upper 20 inches of the substratum is pink clay loam,
<br />and the lower part to a depth of 60 inches or more is
<br />pink loam. In some areas below a depth of 30 inches,
<br />this soil is as much as 25 percent rock fragments. In
<br />some areas the surface layer is fine sandy loam or clay
<br />loam.
<br />Included in this unit are small areas of Forelle, Guben,
<br />and Shawa loarns, Silas Variant soils, and Zoltay clay
<br />loam. Also included are small areas of soils that are wet
<br />as a result of irrigation in higher lying areas. Included
<br />areas make up about 15 percent of the total acreage.
<br />The percentage varies from one area to another.
<br />Permeability of this Work soil is moderately slow.
<br />Available water capacity is high. Effective rooting depth
<br />is 60 inches or more. Runoff is medium, and the hazard
<br />of water erosion is moderate.
<br />This unit is used mainly as irrigated and nonirrigated
<br />cropland. It is also used for livestock grazing and wildlife
<br />habitat and as homesites. Hay and pasture are the main
<br />irrigated crops, and wheat is the main nonirrigated crop.
<br />This unit is well suited to hay and pasture. It has few
<br />limitations. For good establishment of hay and pasture,
<br />prepare a seedbed, drill in the seed, and use
<br />supplemental irrigation. Furrow, border, corrugation, and
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<br />sprinkler irrigation systems are suited to this unit.
<br />Leveling helps to insure the uniform application of water.
<br />Nonleguminous crops respond to nitrogen and
<br />phosphorus, and leguminous crops respond to
<br />phosphorus.
<br />Grazing when the soil in this unit is wet results in
<br />compaction of the surface layer, poor tilth, and excessive
<br />runoff. Proper stocking rates, pasture rotation, and
<br />restricted grazing during wet periods help to keep the
<br />pasture in good condition and to protect the soil from
<br />erosion.
<br />This unit is well suited to nonirrigated small grain
<br />crops. It is limited mainly by a short growing season, low
<br />precipitation in summer, and a moderate hazard of water
<br />erosion from snowmelt. Because precipitation is not
<br />sufficient for annual cropping, a cropping system that
<br />includes small grain and summer fallow is most suitable.
<br />Compaction and excessive cloddiness occur if the soil
<br />in this unit is cultivated when it is too moist. Tillage
<br />should be kept to a minimum. Returning crop residue to
<br />the soil or regularly adding other organic matter improves
<br />fertility, reduces crusting, and increases the water intake
<br />rate. Maintaining crop residue on or near the surface
<br />also reduces runoff, reduces soil blowing, and helps to
<br />maintain soil tilth and organic matter content. Erosion
<br />can be reduced if fall grain is seeded early, stubble -
<br />mulch tillage is used, and tillage and seeding are on the
<br />contour or across the slope. Also, waterways should be
<br />shaped and seeded to perennial grass.
<br />Drainage is beneficial in the small, included areas of
<br />wet soils. Tile drainage can be used to lower the water
<br />table if a suitable outlet is available.
<br />The potential plant community on this unit is mainly
<br />needleandthread, western wheatgrass, big sagebrush,
<br />muttongrass, bluebunch wheatgrass, and low
<br />rabbitbrush. Smaller amounts of serviceberry and
<br />snowberry commonly are also present in the potential
<br />plant community. The production of forage is limited by a
<br />short growing season and low precipitation in summer.
<br />The average annual production of air-dry vegetation is
<br />about 1,500 pounds per acre.
<br />If the range is overgrazed, the proportion of preferred
<br />forage plants decreases and the proportion of less
<br />preferred forage plants increases. Therefore, livestock
<br />grazing should be managed so that the desired balance
<br />of preferred species is maintained in the plant
<br />community.
<br />Management practices suitable for use on this unit are
<br />proper range use, deferred grazing, rotation grazing, and
<br />brush management. Grazing should be delayed until the
<br />soil in the unit is firm and the more desirable forage
<br />plants have achieved sufficient growth to withstand
<br />grazing pressure.
<br />If the range vegetation is seriously deteriorated,
<br />seeding is needed. For successful seeding, prepare a
<br />seedbed and drill in the seed. The plants selected for
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