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16
<br />SOIL SURVEY
<br />county. Slopes are less than 3 pm•ccut. Some areas are
<br />broad in the larger and more gently sloping drainagc-
<br />ways, such as the Badger, San Arroyo, and JAuldy
<br />Creeks, and in places on the South Platte Rircr..111 are
<br />subject, in varying degrees, to flooding from adjacent
<br />slopes and main stream channels. Included in ma]tiling
<br />are small auras of Satanta loam, \unn loam, and Sandy
<br />alluvial land and some very small areas of \Vet alluvial
<br />land.
<br />The surface layer is commonly dark-colored loam
<br />or clay loam about 6 to 10 inches thick. It is normally
<br />noncalcareous. In places sandier materials have been
<br />deposited unevenly ou the. surface b}• floodwaters. The
<br />underlying material is stratified loam, silt loam, and
<br />clay loam and contains varying amounts of fine svtd,
<br />sand, and fine gravel. It is 20 to more than 60 inches
<br />thick, is brown to dark broom, and in places has weal:
<br />structure. It is normally calcareous. Saud or sand and
<br />gravel, stratified with thin leases of silt and loam, are
<br />m some places below a depth of 36 inches.
<br />The soils of this land type absorb tenter at a moderate
<br />rate, and their available• water capacit}• is high. They
<br />are normally well drained. Sutural fertility is high.
<br />The surface layer is easy to work, bat the • hazat•d of
<br />water erosion is eery severe in all cultivated areas be-
<br />cause gullies form easily if fields are not protected from
<br />flooding. Broad areas, more than 200 feet tcide, arc
<br />suitable for dryland cultivatimt and are Icss subject to
<br />gully erosion.
<br />1Lost of this land type is in native grass or in pasture
<br />that has been improved by the use of cheek clams nod
<br />tyatet• sIx•eading. Vatiye grasses include tccstrrn tchcat-
<br />gt.iss, bloc grama and snitchgrass. -\ few areas of suit-
<br />able size are used to produce winter wheat, bnrlry. and
<br />''forage sorghums. Capability unit YIc-1, nmtirrigated;
<br />Overflotc range site; G•ee plmttin~ suittbility _ronp .r.
<br />Loamy alluvial land, gravelly substratum Itvl occurs
<br />ns small areas in major drainageteays. It is n principal
<br />source of gravel. Vcarh• all areas are subject to floodin_*
<br />fran streams. and the floods often arc damnsing.
<br />The soils are ehallotc and stratified. The strata aro
<br />of modcratelc coarse textured to modcratelc fine tex-
<br />tured material that is underlain by ricer sand and
<br />grave]. In some places the soils are sligh[l}• inflttenrerl
<br />by soluble salts.
<br />•The soils of this land type nbsot•b natcr at a rapid
<br />to slow rate. The available tyater capacity is loo-. but
<br />many areas have a high tenter table that is benofirial
<br />to plant growth.
<br />Much of this laud typo is caltit-a[ed and irrigated.
<br />The principal crops are truck crops adapted to the
<br />area, mninh• celer}•. melons, sweet corn. tomatoes. 1Mhtce.
<br />cat•mts, onions, and cabbage. The best grotring conditions
<br />can be maintained if the normal water tablr is crnt-
<br />trolled so that it remains at a depth of 10 to 20 inches
<br />below the surface during the growit>~ srason. (lthor ir-
<br />rigated crops include pasture mixtures that require some
<br />irrigatiot but are partly sustained be the water table
<br />in the gravel layers.
<br />Some of this land type is in native grass, mainly
<br />westert wheatgrass, saltgrass, blue grama. and switch-
<br />grass. The wetter areas produce sedges. rushes, and cat-
<br />tails. This trngetntion is largely sustained b}• the natural
<br />rater table and by Hooding. Little irrigation is needed.
<br />Capability uuit I\".c-1, irrigated; not placed in a range
<br />site; tree planting suitability group :i,
<br />Loamy alluvial land, moderately wet Itwl is in many
<br />drainngeways throughout the county. It is predominantly
<br />in the broader drainageways that have a high eater
<br />table and that formed}' had poor drainage. The areas
<br />are broad iu the larger and more gently sloping drain-
<br />agetcays, espeeiaay m the Soutlt Platte Ricer bottom.
<br />All are subject to damage, in varying degrees, by flood-
<br />ing from adjacent slopes and main stream channels.
<br />Ltcluded in mapping are small areas of Vann loran,
<br />Satanta loam, \Vet alluvial land, and Loant}• alluvial
<br />land, gravelly substratum.
<br />The soils art moderateh' deep. ranging from 20 to 36
<br />inches in depth, over unconsolidated sand and „ravel.
<br />They are dark-colored loam to clay loam in texture
<br />and generally are stratified. The}' are normally noncal-
<br />careous, but they are moderately influenced be soluble
<br />salts in places. Thin lenses of sand, silt. or fine gravel
<br />may be m any of the lacers.
<br />The soils of this land type absorb water at a moderate
<br />to slog- rate, and the available water capacit}' is high.
<br />Artificial drainage is generall}• needed to gron' crops.
<br />Natural fertility is high, but wider the intensive man-
<br />agement used on these soils, artificial supplements are
<br />needed.
<br />Dlost of this land type is irrigated. In these areas.
<br />crops such as sugar heels, corn, small grains, and ycge-
<br />tables can be grown. Alfalfa and irrigated pasture are
<br />tcell adapted. \Vestcrn whcatgrass, saitgrass. blur. _rama.
<br />and switchgrass arc grown in scone areas. Capability unit
<br />IIItc-1, irrigated; not placed in a range site: tree plant-
<br />ing suitability group 5.
<br />Nunn Series
<br />The Vann series consists of well-drained. ncarh' level
<br />soils od terraces. These soils formed in loaulc alluvial
<br />material.
<br />Inn trpresentatit-e itrofile. thr surface. lacer is grac-
<br />ish-bt•otcn loam about G inches thick It is noncalcarcous.
<br />The subsoil is dark grayish-brown and ~racish-brown
<br />clay about 1. inches thick. It is nmtcalrarcous. The
<br />underlyinm material, belotc a depth of 2:3 inches, is
<br />light yellowish-brown and gra}•ish-brown loam and silt
<br />loam. It is highly calcareous and stratified.
<br />Vann soils ab=orb watet• at a nroderatc rate, and the
<br />available water capacity is high. Permeability is slow
<br />in Vttma soils that here a clay loam surface laver, and
<br />it is moderately sloe' in those that bare a loam surface
<br />layer. The entire soil is suitable for plant roots.
<br />Representaticc profile of Nunn loam, 1 [0 3 percent.
<br />slopes, in an area of gra=s, 1.x00 feet east and 2.:i~0 feet.
<br />north of the sauthtcest corner of section 3G, T. i S., R.
<br />65 W.:
<br />dl-0 to G inches, gra rich-brown (lOYR u/?) loam, revs dart
<br />grapieh hrao~n (lOYR 3/?1 wben moist and crushed;
<br />Weal:, fine, granular st ntchn'e: friable; uoncalcareous;
<br />neutral: dear, smooth boundarg.
<br />nl-l. to 0 inches. dark gracish bronn (lOYR 4/?) light da}'
<br />loam, ccr}' dark grn rich brown (IOTR 3/?1 When
<br />umist: neat:. cu:rl:vv. prismatic structure Darling to
<br />Weak, mrdinut. suhn ngnlar hlada' strac[nre: slightly
<br />Ira rd. friablr: thin patclp' rlay flms nn all faces of
<br />p~•d.; uuncalca reanx; neutral; clear, smooth Oouudarp.
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