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<br />24
<br />C~
<br />SOIL SURVEY
<br />be overcome by special care consisting of cultivating only
<br />in the tree row and by leaving a strip of vegetative cover
<br />between the rows. Supplemental irrigation is necessary at
<br />the time of planting and during dry periods. Trees best
<br />suited and having good survival are Rocky Mountain ju-
<br />niper, eastern redcedar, ponderosa pine, Siberian elm,
<br />Russian-olive and hackberry. Shrubs best suited are
<br />skunkbush sumac, lilac and Siberian peashrub.
<br />Openland wildlife such as pheasant, cottontail rabbit
<br />and mourning dove are suited to this soil. In cropland
<br />areas favorable habitat can be developed by establishing
<br />wildlife areas for nesting and escape cover. For
<br />pheasants, undisturbed nesting cover is vital and should
<br />be included in plans for habitat development. Tree and
<br />shrub plantings along fence lines, irrigation ditches, road-
<br />sides and streambanks also help encourage wildlife. Ran-
<br />geland wildlife, including antelope and jackrabbits, can be
<br />encouraged on grasslands by livestock water develop-
<br />ments.
<br />Where this soil is used for homesites and other urban
<br />developments, the primary limiting soil features are occa-
<br />sional flooding and seepage. Sealing methods are required
<br />to overcome excessive seepage condition when the soil is
<br />used for sewage lagoons or landfills. Offsetting engineer-
<br />ing designs and measures, such as embankments and
<br />elevated building pads, are needed to protect homesites
<br />and roads. Special sewage systems must be anticipated
<br />because septic tank absorption fields will not function
<br />pr-0 erly when the soil is flooded. Capability subclass
<br />IYw nonirrigated, IIIw irrigated.
<br />19 Colby loam, 6 to 20 percent slopes. This is a deep,
<br />drained sail on upland ridge crests and hills. It
<br />formed in calcareous, loamy eolian material. It is exten-
<br />sive in the rolling loess area of the south central part of
<br />the county. The average annual precipitation ranges from
<br />17 to 19 inches. Slopes are moderately sloping to
<br />moderately steep.
<br />Included are small areas of Ulysses loam and Norka
<br />loam, both having slopes of 5 to 9 percent.
<br />Typically the surface layer is grayish brown loam about
<br />4 inches thick. The underlying layer is pale brown and
<br />very pale brown, calcareous loam to 60 inches or more.
<br />Permeability is moderate. Effective rooting depth is 60
<br />inches or more. Available water capacity is high. Surface
<br />runoff is rapid, and the erosion hazard is high.
<br />This soil is used almost entirely for grazing. A few
<br />small areas within large areas of cropland soils are used
<br />for nonirrigated cropland. These small areas are com-
<br />monly severely eroded and are best seeded to grass. This
<br />soil is best suited to rangeland.
<br />Rangeland vegetation of this soil consists mainly of
<br />plants from both medium and short grass communities,
<br />including sideoats grama, squirreltail, sedge, little
<br />bluestem, western wheatgrass, needleandthread, and blue
<br />grama. This sail erodes easily when the vegetation is
<br />overgrazed. Grazing management practices needed to
<br />maintain and improve production and range condition are
<br />deferred grazing, planned grazing systems, and proper
<br />grazing use. Where slopes are less than 9 percent, contour
<br />furrowing and pitting improve water penetration and
<br />speed up recovery of areas in fair and poor range condi-
<br />tion. Fencing and livestock water development are effec-
<br />tive in obtaining more uniform distribution of grazing.
<br />Excessive trailing by livestock has caused gully erosion
<br />on this soil.
<br />Windbreaks and endu•onmental plantings are difficult
<br />to establish on this soil because of slope. Special care con-
<br />sisting of summer fallow a year prior to planting, supple-
<br />mental water during planting and early stages of growth,
<br />planting on the contour, and continued cultivation for
<br />weed control is needed to insure establishment and sur-
<br />vival of plantings. Trees best suited and having best sur-
<br />vival are Rocky Mountain juniper, eastern redcedar, pon-
<br />derosa pine, Siberian elm, Russian-olive, and hackberry.
<br />Shrubs best suited are skunkbush sumac, lilac, Siberian
<br />peashrub and American plum.
<br />Rangeland wildlife such as antelope, cottontail rabbits
<br />and coyotes are best adapted on this soil. Forage produc-
<br />tion is typically low and proper livestock grazing manage-
<br />ment is necessary if wildlife and livestock share the
<br />range. Livestock watering developments are also impor-
<br />tant because they are utilized by various wildlife species.
<br />Slope and the inherent low strength are the primary
<br />limiting soil features for homesites and other urban
<br />developments. Special planning and designs can be used
<br />to overcome the low strength and slope. Capability sub-
<br />class VIe nonirrigated.
<br />20-Dacono loam. This is a deep, well drained soil on
<br />upland tablelands. It formed in calcareous, loamy alluvium
<br />that overlies coarse sand and gravel. Average annual
<br />precipitation ranges from 17 to 19 inches. Slopes are
<br />nearly level to gently sloping.
<br />Included in this unit are small areas of Platner loam
<br />and Altvan sandy loam, both having slopes of 0 to 3 per-
<br />cent.
<br />Typically the surface layer is grayish brown loam about
<br />5 inches thick. The subsoil is grayish brown and dark
<br />grayish brown heavy clay loam about 9 inches thick over
<br />light gray silt loam about 6 inches thick. The substratum
<br />is white, calcareous silt loam about 9 inches thick over
<br />light yellowish brown coarse sand and gravel that extends
<br />to 60 inches or more.
<br />Permeability is slow. Effective rooting depth is 60
<br />inches or mare. Available water capacity is moderate.
<br />Surface runoff is slow, and the erosion hazard is slight.
<br />This soil is used mainly for nonirrigated cropland. Some
<br />areas are used for irrigated cropland and grazing. Wheat
<br />is the principal crop grown in nonirrigated areas. Corn, al-
<br />falfa hay, and small grains are the main crops grown in
<br />irrigated areas.
<br />Management concerns in irrigated areas are efficient
<br />use of irrigation water, maintenance of fertility, and con-
<br />trol of soil erosion. This soil is well suited to furrow and
<br />border irrigation methods. Lancl leveling is necessary in
<br />most areas to obtain uniform distribution of water. Irriga-
<br />tion water management is needed for efficient use of
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