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ZQ SOIL SURVEY
<br />grayish-brown, and yellowish-brown fine sand that ex-
<br />tends to a depth of 60 inches or more. The soil is neutral
<br />in the surface layer and mildly alkaline below that depth,
<br />Permeability in these soils is rapid, and the available
<br />water capacity is low. Effective rooting depth is 60
<br />inches or more.
<br />]]lost of the acreage of these soils is in native range.
<br />A small acreage is used for irrigated crops.
<br />Representative profile of Cotopaxi loamy fine sand, 3
<br />to 9 percent slopes, under native grass, 1,560 feet west
<br />and 800 feet south of the northeast corner of sec. 24,
<br />T. 50 N., R. 9 E., Chaffee County:
<br />Al-0 to 3 inches, brown (lOYR 5/3) loamy fine sand; dark
<br />grayish brown (lOYR 4/2) moist• single grained;
<br />loose when dry and moist; many fine and medium
<br />roots; few, scattered, small pebbles; neutral; clear,
<br />smooth boundary.
<br />Cl-3 to 24 inches, brown (lOYR 5/3) fine sand; dark brown
<br />(lOYR 4/3) moist; single grained; loose when dry
<br />and moist; common fine and medium roots; mildly
<br />alkaline; clear, smooth boundary.
<br />C^_-24 to 36 inches, grayish-brown (lOYR 5/2) fine sand;
<br />dark grayish brown (lOYR 9/2) moist; single
<br />grained; loose ashen dry and moist; feu• fine roots;
<br />mildly alkaline; clear, smooth boundary.
<br />C3-36 to 48 inches, pale-brown (lOYR 6/3) fine sand; brown
<br />(lOYR 5/3) moist; single grained; loose when dry
<br />and moist; few cobbles and pebbles; mildly alka-
<br />line; clear, smooth boundary.
<br />C4-48 to 60 inches, light yellowish-brown (lOYR 6/4) fine
<br />sand; yellowish brown (lOYR 5/4) moist; single
<br />grained; loose when dry and moist; mildly alkaline.
<br />The A horizon is dark grayish brown or grayish brown.
<br />Reaction is 6.6 to 7.8. The C horizon ranges from yellowish
<br />brown to dark brown or dark grayish brown. It ranges from
<br />fine sand to coarse sand. Reaction is 7.4 to 7.8. The soil is
<br />less than 15 percent gravel and cobbles.
<br />('olopaxi loamy sand, 3 to 9 percent slopes (CID).-
<br />This soil is on valley slopes and low terraces in the
<br />southeastern part of Chaffee County, east of the Ar-
<br />kansas River. Included with it in mapping are small
<br />areas of Ouray sandy loam.
<br />Surface runoff is slow. The hazard of soil blowing is
<br />high, and that of water erosion is moderate. Most areas
<br />of this soil are in native range that is used for grazing.
<br />A small acreage is irrigated and is used for growing
<br />alfalfa. (Capability unit VIe-1, irrigated, VIe-8, non-
<br />irrigated; Sandy Bench range site)
<br />Dominson Series
<br />The Dominson series consists of somewhat exces-
<br />sively drained soils on terraces and terrace edges. These
<br />soils are very sha]]ou• over cobbles, gravel, and sand.
<br />They formed in gravelly, moderately coarse textured
<br />out~vash. Slopes range from 1 to 45 percent. Elevation
<br />ranges from 7,200 to 8,800 feet. The plant cover is
<br />mainly short and mid grasses, but there is an overstory
<br />of pinyon pine and juniper on some of the steeper
<br />slopes. The average annual precipitation is 11 to 16
<br />inches. The average annual soil temperature is 46° F.,
<br />and the average soil temperature in summer is 64°.
<br />The frost-free season is 75 to 100 days.
<br />In a representative profile the surface layer is dark-
<br />broavn gravelly sandy loam about 6 inches thick. The
<br />next layer is dark-broavn very gravelly sandy loam
<br />about 5 inches thick. Below this is mixed gravel and
<br />cobbles that extend to a depth of 60 inches or more.
<br />The soil is neutral in the uppermost 3 inches and mildly
<br />alkaline below that depth.
<br />Permeability in these soils is very rapid, and the
<br />available water capacity is low. Effective rooting depth
<br />is 60 inches or more.
<br />Most areas of the Dominson soils are in range and
<br />are used for grazing (fig. 7). A small acreage is used
<br />for irrigated hay.
<br />Representative profile of Dominson gravelly sandy
<br />loam, 1 to 9 percent slopes, in native range near the
<br />center of S~V1/~ sec. 15, T. 15 S., R. 78 ~V., Chaffee
<br />County:
<br />All-0 to 3 inches, broom (lOYR 5/3) gravelly sandy
<br />loam; dark brown (lOYR 3/3) moist; weak, thin,
<br />platy structure parting to weak, fine, granular;
<br />slightly hard, very friable, nonsticky; many fine
<br />and medium roots; 15 percent gravel and cobbles;
<br />neutral; clear, smooth boundary.
<br />A12-3 to 6 inches, broom (lOYR 5/3) gravelly sandy loam;
<br />dark brown (lOYR 3/3) moist; weak, medium, sub-
<br />angular blocky structure; slightly hard, friable,
<br />nonsticky; many fine and medium roots; 15 percent
<br />gravel and cobbles; mildly alkaline; clear, wavy
<br />boundary.
<br />AC-6 to 11 inches, dark-brown (lOYR 4/3) very gravelly
<br />sandy loam; dark brown (lOYR 3/3) moist; weak,
<br />medium, subangular blocky structure; slightly hard,
<br />triable, nonsticky; common fine and medium roots;
<br />50 percent gravel and cobbles; mildly alkaline;
<br />gradual, wavy boundary.
<br />IIC-11 to 60 inches, mixed igneous cobbles, grave], and sand;
<br />lime coatings in places on underside of large gravel.
<br />The A horizon generally ranges from 5 to 8 inches in
<br />thickness, but where there is no AC horizon, the A horizon
<br />is 7 to 15 inches thick. This horizon is very dark brown or
<br />dark brown. Gravel and cobbles cover 5 to 25 percent of the
<br />soil surface. Reaction ranges from 6.6 to 7.8. Depth to the
<br />IIC horizon ranges from 8 to 16 inches.
<br />Dominson gravelly sandy loam, 1 to 9 percent slopes
<br />(DoD).-This soil is on alluvial fans and high terraces in
<br />nearly all parts of Chaffee County. It has the profile
<br />described as representative of the series. Included with
<br />this soil in mapping are small areas of St, Elmo
<br />gravelly sandy loam, 1 to 3 percent slopes.
<br />Surface runoff is medium, and the hazard of erosion
<br />is moderate. About 80 percent of the acreage is in
<br />range that is used for grazing, The remaining 20 per-
<br />cent is in irrigated hay, mainly alfalfa. Most of the
<br />irrigation is in areas where slopes are 3 to 5 percent.
<br />(Capability unit VIe-], irrigated, VIe-3, nonirrigated;
<br />Dry Illountain Outwash range site)
<br />Dominson ravelh• sand • loam 9 to 95 ercent slopes
<br />Do .- is sol ism ong, narrow areas a ong errace
<br />edges in nearly all parts of Chaffee County. It has a
<br />profile similar to that described as representative of
<br />the series, but the depth to the underlying material is
<br />less than 11 inches, and in most places there is a larger
<br />amount of gravel and cobbles on the surface. Included
<br />with this soil in mapping are small areas of Rough
<br />broken land and St. Elmo gravelly sandy loam, 9 to
<br />95 percent slopes.
<br />Surface runoff is rapid, and the hazard of erosion
<br />is severe. Al] of this soil is in grass and is used for
<br />grazing. Some areas have an overstory of pinyon pine
<br />and juniper. (Capability unit VIIe-1, nonirrigated;
<br />woodland suitability group 3; Dry Mountain Outwash
<br />range site)
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