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SOIL SURVEY
<br />one Series
<br />he Rosane series consists of poorly drained soils in
<br />swales on uplands and in drainage channels on
<br />;om lands. These soils are moderately deep over
<br />1, gravel, and cobbles. They formed in moderately
<br />:se textured, mixed alluvium. Slopes range from 1
<br />i percent. Elevation ranges from 8,200 to 10,500
<br />The plant cover is rushes, sedges, willows, and
<br />er-tolerant grasses. The average annual precipita-
<br />is 12 to 25 inches. The average annual soil tem-
<br />Aure is 38` F., and the average soil temperature in
<br />imer is 46`. The frost-free season is 15 to 80 days.
<br />a a representative profile a thin organic mat over-
<br />the surface layer. The underlying surface layer is
<br />F dark-brown loam and black sandy loam, 17 inches
<br />k, that has dark-brown mottles. The subsoil is very
<br />k grayish-brown sandy loam, about 13 inches thick,
<br />t has many yellowish-brown mottles. The substra-
<br />i is gravel, sand, and cobbles that extends to a depth
<br />;0 inebes. The profile is neutral throughout.
<br />'ermeability in these -soils is moderately rapid, and
<br />available water capacity is low. Effective rooting
<br />tb is 60 inches or more. A seasonal water table
<br />to the surface. Rosane soils are subject to (re-
<br />nt overflow.
<br />lost of the acreage of these soils is flood-irrigated
<br />ssland and is used for grazing.
<br />;epresentative profile of Rosane loam, 1 to 5 per-
<br />t slopes, in a pasture, near the center of sec. 32,
<br />9 S.. R. 80 W . , Lake County :
<br />01-6 inches to 0, organic mat; composed of roots and
<br />undecomposed organic materials.
<br />Ailg-0 veto 6 inches, dark grayish-brown (10YR 4/2) loam;
<br />ry dark brown ( OYR 2//2) moist; common, fie,
<br />distinct, dark-brown (7.5YR 4/4) mottles; moderate,
<br />fine, granular structure; slightly hard, friable,
<br />slightly sticky; many fine roots; neutral; clear,
<br />smooth boundary.
<br />A12g-6 to 17 inches, dark-gray (5Y 4/1) sandy loam; black
<br />(5Y 2/2) moist; many, medium, distinct, dark-brown
<br />(7.5YR 4/4) mottles; weak, fine, subangular blocky
<br />structure; slightly hard, friable, nonsticky; many
<br />fine and medium roots; neutral; gradual, smooth
<br />boundary.
<br />B2g-17 to 30 inches, grayish-brown (10YR 5/2) heavy
<br />sandy loam; very dark grayish brown 00YR 3/2)
<br />moist; many, coarse, distinct, yellowish-brown
<br />(10YR 5/6) mottles; massive; slightly hard, friable,
<br />slightly sticky; common medium roots; neutral;
<br />smooth boundary.
<br />Mg--30 to 60 inches, mixed gravel, cobbles, and sand;
<br />many, large, prominent, high-chrome mottles.
<br />The A horizon ranges from very dark grayish brown to
<br />black in color and from sandy loam to loam in texture.
<br />Mottles range from few to many and from distinct to
<br />prominent. A contrasting 37C horizon of gravel and cobbles
<br />is at a depth of 20 to 40 inches.
<br />Mane loam, l to 5 percent, slopes (RtC).-This soil
<br />in upland swales and in drainage channels of the
<br />?d plains in all parts of Lake County. The areas
<br />ierally are long and narrow because they follow
<br />river and stream channels. Included with this soil
<br />mapping are small areas of Newfork gravelly sandy
<br />m and Marsh.
<br />'early all the acreage of this soil is flood irrigated
<br />l is in pasture that is grazed by cattle. (Capability
<br />t F'w-1, irrigated)
<br />Rough Broken Land
<br />Rough broken land is mapped in two units in the
<br />Chaffee-Lake Area-Rough broken land and Rough
<br />broken land, cold.
<br />Rough broken land (Ru) is a gently sloping to steep
<br />land type that consists of sediments of the Dry Union
<br />Formation. It is in the southern and central part of
<br />the survey area in Chaffee County. Rough broken land
<br />is made up of highly stratified, gray, brown, and pink-
<br />ish-yellow silt; clay that has lenses of sand; and gravel
<br />and cobbles. The strata of these materials range from
<br />a few inches to many feet in thickness. The layers of
<br />deposition are not uniform and differ within short
<br />distances.
<br />Most of this land is calcareous and has pockets of
<br />high lime accumulation. A thin cap of gravel and
<br />cobbles covers most of the surface. This land has been
<br />dissected by erosion and appears as long, fingerlike
<br />protrusions onto the valley floor. Near the bottom of
<br />the valley floor, there are isolated areas that are a
<br />result of more recent erosion. Much of the land is no
<br />longer a high sediment producer because of the gravel
<br />and cobbles on the surface.
<br />Surface runoff is rapid, and the hazard of erosion is
<br />high. The plant cover is pinyon pine and juniper and
<br />an understory of blue grama, Indian ricegrass, moun-
<br />tain mutely, and other grasses. Included with this land
<br />type in mapping are small areas of Gravelly alluvial
<br />land, Badland, Nawksell sandy loam, Shrine clay loam,
<br />and Costilla gravelly sandy loam. (Capability unit
<br />VIle-1, nonirrigated; woodland suitability group 3)
<br />Rough Broken Land., Cold
<br />Rough broken land, cold (Rv) is a gently sloping to
<br />steep land type that consists of sediments of the Dry
<br />Union Formation. It is in the southern part of Lake
<br />County. Rough broken land, cold, is made gray, of Ter-
<br />tiary sediments that are highly stratified, and pinkish-yellow silt; clay that has lenses of sand;
<br />and gravel and cobbles. The strata of these materials
<br />range from a few inches to many feet in thickness.
<br />They are not uniform and differ within short distances.
<br />Most of this land type is calcareous and has pockets
<br />of high lime accumulation. A cap of gravel and cobbles
<br />covers most of the areas. This land has been dissected
<br />by erosion and appears as long fingerlike protrusions
<br />onto the valley floor. Much of the land is no longer a
<br />high sediment-producing area because of the super-
<br />ficial cap of gravel and cobbles.
<br />Surface runoff is rapid, and the hazard of erosion
<br />is high. The plant cover is native grasses. Included
<br />with this land type in mapping are areas of Pierian
<br />gravelly sandy loam and Badland.
<br />This mapping unit is similar to Rough broken land,
<br />but it is at higher elevations, is in colder climate,
<br />and receives more precipitation annually. All of
<br />Rough broken land, cold, is in native grasses that
<br />are grazed by cattle and sheep. (Capability unit
<br />VIle-1, nonirrigated)
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