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<br />DELTA-MONTROSE AREA, COLORADO
<br />Cleo-lr, to 32 inches, grncellp clap innw; cerp ryale brewn
<br />(lOYR 8/3) when dry, cerp pole brmcn (lOYR i/3)
<br />when moist; wassire; hard whcu dry, friable +vhen
<br />woist; strong nccumuletioo oP secondary calcium
<br />cnrbonnte in finely divided forms; 90 pettent grncel;
<br />cnlcareovs; pH 8.2; gradual, smooth boundnrp.
<br />C2ca-3? to GO inches, cerp grncellc cloy loom; cerc pole
<br />brown (lOSR 7/4) when drp, light pellnwish brown
<br />(lOTR G/9) when moist; wa9gi ce; har[l when drp,
<br />friable when moist; moderate to strong nnvmnla-
<br />tion oP secondary calciuw carbonntc nrcurrinR as
<br />concretions and ns routings nn the underside of
<br />rocks; CO percent gee eel: Rrnrlrs dmemcnrd to
<br />gravel and sand at a depth below 60 inches; cnl-
<br />c•nreous; pH 8?.
<br />Undisturbed Dfesa soils normally have a thin surface
<br />layer of loam, but in this Aren the surface layer is made
<br />up of clay loam brought up from the subsoil. Typical
<br />Dfesa soils are nmlcalcareous in the surface ]nyer and
<br />in the upper part of the subsoil, but. locally they are
<br />n-eakly calcareous throughout because they have been
<br />irrigated with calcareous water The gravel content
<br />of the subsoil ranges from 0 to as much as ?0 percent.
<br />In the substratum it ranges from 30 to 70 percent.
<br />In many places Dfesa soils are adjacent. to Dlack soils,
<br />which lack the very gravelly and cobbly lower subsoil
<br />and substratum typical of I11esa soils. Dfesa soils re-
<br />semble Hinman smis but. have a coarser teetered sub-
<br />soil. Tbey closelc resemble Orchard soils, but. their par-
<br />ent material, unlike that. of Orchard soils, contained little
<br />or no material derived from basalt or from ferromagnesinn
<br />minerals.
<br />In their natural state, Dfesa soils support a good cover
<br />of galleta, Indian ricegrass, needle-and-t.hrenrl, blue
<br />grams, and cactus. If irrigated, they are higldy produc-
<br />tave and are suited to most crops commonly grown in
<br />the Area.
<br />Mesa clay loam, 0 to 2 percent slopes (MIAI.-This soil
<br />is on top of high mesas. It has a profile similar to the
<br />one described as typical of the Dfesa series. The total
<br />acreage in this Area is large, and most of it is in the
<br />western half.
<br />If irrigated, this soil can be used successfully for
<br />tilled crops. Because the subsoil is gravelly, there is no
<br />need to provide underdrainage before irrigation starts.
<br />The water-holding capacity is fair, at ]east to n depth
<br />of 40 to GO inches, because enough clay loran is mieed
<br />with the gravel. These soils are not highh' susceptible
<br />to erosion. (Capability unit VIe-1 nonirrigated; IIe-1
<br />irrigated)
<br />Mesa clay loam, 2 to 5 percent slopes (MIBL-This soil
<br />is on high terraces. It has a profile similar to the one
<br />described as typical of the Dfesa series. Most of the
<br />acreage is west of the Uncompahgre River.
<br />If irrigated and well managed, this soil can be used
<br />successfully for tilled crops, but it. is not so easy to irri-
<br />ggnte as ,\[esa clay loam, 0 to 2 percent slopes. Unrler-
<br />drainnge is free because of the gravelly substratum, and
<br />unless bedrock is near the surface, drainage and salinity
<br />problems ore not ]il:ely to develop. Phis soil is not
<br />highly susceptible to erosion. (Capability unit VIe-1
<br />nonirrigated; IIIe-1 irrigated)
<br />Mesa clay loam, 5 to 10 percent slopes (MICL-This
<br />soil is on old mesas mul terraces. It has a profile simi-
<br />lar to [he one described as typical of the Dfesa series, but
<br />the surface Inver and subsoil are thinner and there is a
<br />~a5~ 3
<br />23
<br />higher percentage of gravel in the subsoil. This soil is
<br />nest of the Uncompahgre River.
<br />Itecause of the slope, this soil is difficult to manegge,
<br />and it generally is used as native range. It is moderately
<br />susceptible to erosion. (Capability unit VIe-I nomrrl-
<br />gated; I\'e-~' irrigated)
<br />Mesa gravelly clay loam, 0 to 2 percent slopes IMoAI.-
<br />This soil is on old ]sigh terraces. It has a profile similar
<br />to the one described as typical of the Mesa series but
<br />the surface In}cr is Li to 30 percent gravel and co~ble-
<br />stones. 1'he nlniu acreage is west of the Uncompahgre
<br />River.
<br />Some of this soil is tilled, but gravel and cobble-
<br />stones make tillage difficult and are5tard on farm ma-
<br />chinery. Conte of the larger stones should be removed.
<br />'Phis soil is not highly suscepptible to erosion. (Capa-
<br />bilitc unit V1e.-1 nonirrigated; IIIs-2 irrigated)
<br />Mesa gravelly clay loam, 2 to 5 percent slopes IMoel.-
<br />This soil is partk on old high terraces and alluvial fans
<br />and partl}- alnn;,r small drainageways that have cut into
<br />the terraces. The profile is similar to the one described
<br />as typirnl of the \Irsa series, but. the surface layer is
<br />15 to 30 percent gravel and cobblestones. Dfost of the
<br />acreage is west of the, Uncompabgre River.
<br />This soil supports a good cover of gaffers, needle-and-
<br />thread, blue ~rmnn, and cactus. If Irrigated, it con be
<br />used snccessfulk for tilled crops, but stones and g~r•avel
<br />make tillage difficult and are hard wt f;u•m machinery.
<br />Some of the larger stones should be removed. This soil
<br />is not highh• susceptible to erosion. (Capability unit
<br />\'Ie-1 nonirrigated; IIIe-1 irrigated)
<br />Mesa gravelly clay loam, 5 to 10 percent slopes
<br />(MoCI.-Phis soil is on high terraces and along the small
<br />streams that have cut into the terraces. It has a pro-
<br />file similar to the one desmribed as typical of rho Dfesa
<br />ser•ics, but the surface layer is 1:. to 40 percent gravel
<br />and cobblestones. host of the acreage is }test of the
<br />Uncompahgre Liver.
<br />This geIlCCIlIIy is used as native range. It is used as
<br />cropland only where it occurs in fields with soils that
<br />are tilled. This soil is difficult to irrigate beranse of the
<br />slope and is difficult to till because of the grovel and
<br />cobblestones. It is not highly susceptible to erosion.
<br />(Capability unit VIe-1 nonirrigated; 1\'c-2 irrigated)
<br />Mesa gravelly clay loam, shale substratum, 0 to 2
<br />percent slopes (MsAI.-This soil is nt the outer edge of old
<br />terraces where alluvial sediments are thin and overlie
<br />sedimentary rock. It has a profile similar to the one
<br />described as typical of the Dfesa series, but. the surface
<br />layer is 15 t~ 40 percent gravel and wbblestmteS, and
<br />the depth to shale beds is between :3n and GO II1Che5.
<br />Dlost of the acreage is west of the lincompabgre River.
<br />'Phis soil can be used sttccessfttlly for tilled crops, but
<br />the gravel and cobblestones make. t.illa~*e difficult and
<br />are hard rat farm machinery. In addition, the shale sub-
<br />strakum restricts sttbsoi] drainage and is likel}• to cause
<br />emblems of drainage and salinity. 'I'bis soil is not
<br />highk SnsCClltIIIIC to erosion. (Capability unit VIe-1
<br />mm~irrigated; IVs-O irrigated)
<br />Mesa gravelly clay loam, shale substratum, 5 to 10 per-
<br />cent. slopes IMsCI~-This soil is partly at. the outer edge of
<br />Ligh ICI'1':1CCS ++'11e1'C a11t1y1a1 deposits ore thin :nut overlie
<br />sedimentary rock and partly along small streams that
<br />drain die terraces. The profile is similar to the one de-
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