2015-01-12_REVISION - M1980183 (5)

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I I . 16 SOIL SURVEY I county: Slopes are less than 3 percent. Some areas are Capability unit IVw-i irrigated; not placed in a range broad in the larger and more gently sloping drainage- site;tree planting suitability group 5. ways, such as the Badger, San Arroyo, and Muddy Loamy alluvial land,moderately wet awl is in many Creeks,and in places on the South Platte River. All are drainageways throughout the county.It is predominantly I subject, in varying degrees, to flooding from adjacent in the broader drainageways that have a high water slopes and main stream channels. Inchlded in mapping table and that formerly had poor drainage. The areas are small areas of Satanta loam, Nunn loam, and Sandy are broad in the larger and more gently sloping drain- alluvial land and some very small areas of Wet alluvial ageways, especially in the South Platte River bottom. land. All are subject to damage,in varying degrees by flood- I The surface layer is commonly dark-colored loam ing from adjacent slopes and main stream channels. or day oam about 6 to 10 inches thick. It is normally Included in mapping are small areas of Nunn loam noncalccareous. In places sandier materials have been Sating* loim, Wet alluvial land; and Loamy alluvial deposited unevenly on tho surface by floodwaters, The • land, gravelly substratum. I underlying material is stratified loam, silt loam, and The soils are moderately deep, ranging from 20 to 36 clay loam and contains varying amounts of fine sand, inches in depth, over unconsolidated sand and gravel. sand, and fine gravel. It is 20 to more than 60 inches They are dark-colored loam to clay loam in texture thick, is brown to dark brown, and in places has weak and generally are stratified. They are normally noncal-• structure. It is normally caleareous. Sand or sand and citreous, but they are moderately influenced by soluble I gravel, stratified with thin lenses of silt and loam, are salts in places. Thin lenses of sand, silt, or fine gravel in some places below a depth of 36 inches. may be in any of the layers. The soils of this land type absorb water at a moderate the soils of this land type absorb water at a moderate rate, and their available water capacity is high. They to slow rata, and the available water capacity is high. I are normally well drained. Natural fertility is high. Artificial'drainage is generally needed to grow crops. The surface layer is easy to work, but the. hazard,of Natural fertility is high, but under the intensive man- water erosion is very severe in all cultivated areas be- agement used on these soils, artificial supplements are cause gullies form easily if fields are not protected from needed. flooding. Broad areas, more than 200 feet Ride, are Most of this land type is irrigated. In these areas, I suitable for dryland cultivation and are less subject to crops such as sugar beets,corn,small grains, and vege- gully erosion. tables can be ggrroown. Alfalfa and irrigated pasture are Most of this land type is in native grass or in pasture well adapted.Western wheatgrass,saltgrass,blue grams, that has been improved by the use of check dams and and switchgrass are grown in some areas.Capability unit I water spreading. Native grasses include western.wheat- IIIw-I,irrigated;not placed in a range site; tree plant- grass,blur grams, and switchgrass. A few areas of suit- ing suitability group 5. able size are used to produce winter wheat, barley, and forage sorghums. Capability unit VIe-I. nonirrigated; Nunn Series • Overflow range site; tree planting suitability group 5. I Loamy alluvial land,gravelly.aubstratum its)'occurs• The Nunn series consists of well-drained, nearly level as small areas in major drainegeways. It is a principal' soils on terraces. These soils formed in loamy alluvial source of gravel. Nearly all area are subject to flooding material. from streams,and the floods often are damaging. In a,representative profile, the surface layer is gray- ' The soils are shallow and stratified. The strata are ish-brown loam about 6 inches thick.it isnoncalcareous. of moderately coarse textured to moderately fine ter- The subsoil is dark grayish-brown and grayish-brown tined material that is [underlain by river sand and day about 17 inches thick It is nonealcareous. The gravel. In some places the soils are slightly influenced underlying material, below a depth of 23 inches, is by soluble salts. . . light yellowish-brown and grayish-brown loam and silt I The soils of this land type absorb water at a raid loam. It is highly calcareous and stratified. to slow rate. The available water capacity is low, but Nunn soils absorb water at a moderate rate, and the many areas have a high water table that is beneficial available water capacity is high. Permeability is slow to plant growth. . in.Nunn soils that have a clay loans surface layer,and I Much of this land type is cultivated and irrigated. it is moderately slow in those-that have a loam surface The principal crops are truck crops adapted to the layer. The entire soil is suitable for plant roots. area,mainly celery,melons,sweet corn,tomatoes,lettuce, Representative profile of Nunn loam, 1 to 3 percent carrots,onions,and cabbages The best growing conditions slopes,in an;area'of grass,1,500 feet east and 2,5•t0feet can be maintained'if the normal water`tole. is con- north of the southwest corner of section 36, T. 3 S., R. I trolled so that it remains at a depth of 10 to-20 inches 65 w.: below the surface during the growing season. Other it-• rigated crops include pasture mixtures that require some sl-0 to 6 loebes,erartab brown(10Th 5/2) loam,very dark irrigation but are partly sustained by the water table grayish brown (10YR 312) when moist and crnahed; weak,line,granular structure;friable;noncakareous; I in the gravel layers. aeatral;clear,smooth boundary. Some of this land type is in native grass, mainly A1--C to 8 inches,dark graybh-brown (10TR 4/2) light clay western >aeheatgtass, saltgrass, blot grams, and switch- loam, very mark grayish brown,(10YR 3/2) when gram. The wetter areas produce sedges, rushes,and cat- moist: weak. coarse, prismatic structure tutting to tails.This vegetation is largely sustained by the natural weak,medium,subangular blocky structere:slightly I �y y •hard,friable; thin patchy day Sims on all faces of water table and by flooding. Little irrigation is needed. peas;noncal canoes;neutral;clear,smooth boundary. I I