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<br />EXHIBIT I/J
<br />(COnt'd)
<br />SOIL DESCRIPTIOPIS
<br />1-Altvan loam, 0 to 1 percent elopes. This is a deep,
<br />well drained soil on terraces at elevations of 4,500 to x,900
<br />feet. It formed in old alluvium deposited by the major
<br />rivers. Included in mapping are small areas of soils that
<br />show evidence of poor drainage. Also included are small,
<br />long and narrow areas of sand and gravel deposits.
<br />Typically the surface layer of the Altvan soil is grayish
<br />brown loam about 10 inches thick. The subsoil is brown
<br />and light yellowish brown clay loam and sandy clay loam
<br />about I5 inches thick The substratum is calcareous loamy
<br />sand about 6 inches thick over gravelly sand.
<br />Permeability and available water capacity are
<br />moderate. The effective rooting depth is 'LO to 40 inches.
<br />Surface runoff is slow, and the erosion hazard is low.
<br />This soil is used almost entirely for irrigated crops. It
<br />is suited to all crops commonly grown in the area, includ-
<br />ing corn, sugar beets, beano, alfalfa, small grain, potatoes,
<br />and onions. An example of a suitable cropping System is 3
<br />to 4 years of alfalfa followed by corn, corn for silage,
<br />sugar beets, small grain, or beans. The high clay content
<br />and the rapidly permeable substratum slightly restrict
<br />some crops.
<br />All methods of irrigation are suitable, but furrow ir-
<br />rigation is the moat common (fig. 4). Proper irrigation
<br />water management is essential. Barnyard manure and
<br />commercial fertilizer are needed for top yields.
<br />Windbreaks and environmental plantings of trees and
<br />shrubs commonly grown in the area are generally well
<br />suited to this soil. Cultivation to control competing
<br />vegetation should be continued for as many years as
<br />possible following planting. Trees that are best suited and
<br />have good survival are Rocky Mountain juniper, eastern
<br />redcedar, ponderosa pine, Siberian elm. Russian-olive, and
<br />hackberry. The shrubs best suited are skunkbush sumac,
<br />lilac, Siberian peashrub, and American plum.
<br />This soil can produce habitat elements that are highly
<br />suitable Cor openland wildlife, including pheasant, cotton-
<br />tail, and mourning dove. Such crops as wheat, corn, and
<br />alfalfa provide suitable habitat for openland wildlife,
<br />especially pheasant. Tree and shrub plantings and
<br />undisturbed nesting cover would enhance openland wil-
<br />dlife populations.
<br />This Altvan soil has fair to good potential for urban
<br />and recreational development. The chief limiting soil fea-
<br />tures for urban development are the shrink-swell poten-
<br />tial of the subsoil as it wets and dries and the rapid
<br />permeability of the sand and gravel substratum. Septic
<br />tank absorption fields function properly, but in places the
<br />substratum does not contain enough fines to properly
<br />filter the leachate. Sewage lagoons require sealing.
<br />Lawns, shrubs, and trees grow well. Capability subclass
<br />Its irrigated.
<br />3-Aquolle and Aquente, gravelly substratum. This
<br />nearly level map unit is on bottom lands and flood plains
<br />of all the major streams in the survey area Aquolls,
<br />which have a dark colored surface layer, make up about
<br />60 percent of the unit. Aquents, which have a lighter
<br />colored surface layer, make up about 35 percent. About 5
<br />percent is Aquep[s and Bankard sandy loam.
<br />These are deep, poorly drained soils that formed in
<br />recent alluvium. No one pedon is typical. Commonly thr•
<br />soils have a mottled, mildly alkaline to moderately al-
<br />kaline loamy or clayey surface layer xnd underlying
<br />material and are underlain by sand or sand and gravel
<br />within 48 inches. In places [hey have a gleyed layer in the
<br />underlying material.
<br />Most of the acreage is subject to flooding. The water
<br />table is at or near the surface early in spring and recedes
<br />to as deep as 48 inches late in fall in some years.
<br />These soils are used for rangeland and wildlife habitat.
<br />Some small areas have been reclaimed by major drainage
<br />and leveling and are used for irrigated crops.
<br />The potential native vegetation is dominated by alkali
<br />sacaton, switchgrass, and western whea[grass. Saltgrass,
<br />sedge, rush, and alkali bluegrass are also prominent.
<br />Potential production ranges from 3,000 pounds per acre in
<br />favorable years to 2,000 pounds in unfavorable years. As
<br />range condition deteriorates, the switchgrasa, alkali
<br />sacaton, and western wheatgrasa decrease and saltgrass.
<br />sedge, and rush increase.
<br />Management of vegetation should be based on taking
<br />half and leaving half of the total annual production. Seed-
<br />ing is difficult and costly because numerous tdlage prac-
<br />tices are required to eliminate the sal[grass snd.
<br />Switchgtase, western wheatgrass, alkali sacaton, tall
<br />wheatgrasa, and tall fescue are suitable for sealing. They
<br />can be seeded into a clean, Ctrm seedbed. Seedbed
<br />preparation usually requires more than 1 yeaz to
<br />eliminate the saltgrass sod. A grass drill should be used.
<br />Seeding early in spring has proven most successful.
<br />Wetland wildlife, especially waterfowl, utilize this unit.
<br />The wetland plants provide nesting and protective cover,
<br />as well as some food. The nearby irrigated cropland,
<br />where wildlife obtain much of their food and trod protec-
<br />tive cover, makes this unit valuable to both wetland and
<br />openland wildlife.
<br />Openland wildlife, especially pheasant, use this unit for
<br />cover and nesting. Deer find excellent cover in some
<br />areas.
<br />These soils have good potential as a source of sand and
<br />gravel. Capability subclass VIw; Salt Meadow range site.
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