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<br />10 SOIL SURVEY
<br />Runoff is slow, and the hazard of erosion is slight.
<br />In places the soil is subject to occasional, brief flooding.
<br />A seasonal high water table is at a depth of 2 to 3 feet.
<br />Aeration is poor below a depth of 2 or 3 feet because of
<br />the high water table. A ]o~v to moderate concentration
<br />of salts tends to accumulate from irrigation water or
<br />from evapol•ation of upward-moving capillary water
<br />from the seasonal high water table.
<br />This soil is better suited to irrigated Pasture than
<br />to other uses. The sul•face layer is difficult to cultivate
<br />because of the silty clay texture. The native grasses
<br />are alkali sacaton alld inland saltgrass. Capability
<br />units IIIw-1, irrigated, and VIw-1, nonirrigated; Salt
<br />Meadow range site.
<br />Arvada Series
<br />The Arvada series consists of deep, well-drained
<br />soils. These soils formed on terraces in loamy alluvium
<br />derived mostly from mixed sedimentary rock. The
<br />slope is 0 to 4 percent, and elevation is 4,500 to 5,400
<br />feet. The average annual precipitation is 12 inches.
<br />The average annual temperature is 53° F, and the
<br />frost-free season is 145 to 175 days. The native vege-
<br />tation is mainly short plains grasses.
<br />In a representative profile the surface layer is light
<br />brownish-gray sandy loam about 3 inches thick. The
<br />upper part of the subsoil is brown heavy clay loam
<br />about 2 inches thick, and the lower part is pale brown
<br />and very pale brown heavy clay loam about 12 inches
<br />thick. Below that is very pale brown light clay loam
<br />that extends to a depth of 60 inches or more.
<br />Permeability is very slow, and the available water
<br />capacity is high. The surface layer and the upper part
<br />of the subsoil are moderately alkaline, and the lower
<br />part of the subsoil and the substratum are strongly
<br />alkaline. The root zone extends to a depth of 60 inches
<br />or more. These soils are used for grazing.
<br />Representative profile of Arvada sandy loam, in an
<br />area of Arvada-Keyner association, in native grass,
<br />0.2 mile south and 0.05 mile west of the northeast
<br />corner of sec. 30, T. 19 S., R. 63 W.
<br />A2-0 to 3 inches, light brownish-gray (lOYR 6/2) sandy
<br />loam, dark grayish brown (lOYR 4/2) when moist;
<br />weak, very fine, granular structure; slightly hard, very
<br />friable; nonsticky and nonelastic; calcareous; moder-
<br />ately alkaline; abrupt, smooth boundary.
<br />B21t-3 to 5 inches, brown (lOYR 5/3) heavy clay loam,
<br />dark brown (lOYR 4/3) when moist; moderate, medium,
<br />columnar atructu re; very hard, firm; slightly sticky and
<br />plastic; thin, continuous, clay films on pads; calcareous;
<br />moderately alkaline; clear, smooth boundary.
<br />B22t-5 to 12 inches, pale-brown (IOYR 6/3) heavy clay
<br />loam, brown (lOYR 5/3) when moist; moderate, medi-
<br />um, subangular blocky structure; very hard, firm;
<br />slightly sticky and plastic; thin, continuous, clsy films
<br />on pads; calcareous; strongly alkaline; clear, smooth
<br />boundary.
<br />Baca-12 to 17 inches, very pate brown (IOYR 7/3) light
<br />clay loam, brown (lOYR 5/3) when moist; moderate,
<br />medium, subangular blocky structure; hard, friable;
<br />slightly sticky and plastic; thin, patchy, clay films on
<br />pads; calcareous; few small masses of lime; strongly
<br />alkaline; clear, smooth boundary.
<br />Clca-17 to 43 inches, very pale brown (lOYR 7/4) light
<br />clay loam, yellowish brown (lOYR 5/4) when moist;
<br />weak, medium, subangular blocky structure; hard, firm;
<br />slightly sticky and plastic; calcareous; common, medium,
<br />soft masses of lime and fine threads of crystalline
<br />gypsum; strongly alkaline; gradual, smooth boundary.
<br />C2--43 to 60 inches, very pale brown (lOYR 7/4) light clay
<br />loam, yellowish brown (lOYR 5/4) when moist; massive;
<br />hard, firm; sticky and plastic; calcareous; strongly
<br />alkaline.
<br />The A horizon is sandy loam and loamy sand 3 to 8 inches
<br />thick. The B2t horizon is clay or heavy clay loam 6 to 9
<br />inches thick. In places it is leached of lime to a depth of 11
<br />inches.
<br />AR-Arvada-Keyner association. This association is
<br />mostly in the northeastern part of the survey area. It
<br />is made up of about 55 percent Arvada sandy loam
<br />and 30 percent Keyner loamy sand. The slope is 0 to 4
<br />percent. Areas of these soils are irregular in shape
<br />and cover as much as 600 acres. The Arvada soil is
<br />nearly level or slightly concave and is on broad ter-
<br />races. The Keyner soil is on side slopes of terrace
<br />drainageways.
<br />The Arvada and Keyner soils in this association
<br />have the profile described as representative of their
<br />series. On about 25 percent of the acreage erosion has
<br />removed the subsurface layer, leaving barren slick-
<br />spots.
<br />Included with these soils in mapping are areas of
<br />Limon silty clay loam that make up about 10 percent
<br />of the acreage and areas of Razor clay, eroded, that
<br />make up about 5 percent.
<br />Runoff is slow on the Arvada soil and medium on
<br />the Keyner soil. The hazard of erosion is slight.
<br />These soils have potential for wildlife habitat if
<br />water for wildlife is provided. The native grasses are
<br />mainly alkali sacaton, blue grams, and garrets. Four-
<br />wing saltbush, greasewood, and cactus are abundant
<br />in places. Capability unit VIe-2, nonirrigated; Arvada
<br />soil in Salt Flats range site; Keyner soil in Alkaline
<br />Plains range site.
<br />Baca Series
<br />The Baca series consists of deep, well-drained soils.
<br />These soils formed in loess on uplands. The slope is 0
<br />to 3 percent, and elevation is 4,400 to 5,400 feet. The
<br />average annual precipitation is 12 inches. The average
<br />annual temperature is 53° F, and the frost-free season
<br />is 145 to 175 days. The native vegetation is mainly
<br />short plains grasses.
<br />In a representative profile the surface layer is gray-
<br />ish-blown silty clay loam about 5 inches thick. The
<br />upper part of the subsoil is brown heavy silty clay
<br />about 8 inches thick, and the lower part is pale-brown
<br />silty clay loam about 8 inches thick. The underlying
<br />material is pale-brown silt loam and light yellowish-
<br />brown loam that extends to a depth of 60 inches or
<br />more.
<br />Permeability is moderately slow, and the available
<br />water capacity is high. The surface layer and subsoil
<br />are mildly alkaline, and the underlying material is
<br />moderately alkaline. The root zone extends to a depth
<br />of more than 60 inches. These soils are used for graz-
<br />ing and irrigated crops.
<br />Representative profile of Baca silty clay loam, in
<br />native grass, 0.3 mile east and 0.1 mile north of the
<br />southwest corner of sec. 34, T. 31 S., R. 66 W.
<br />AI-0 to 5 inches, grayish-brown (lOYR 5/2) silty clay
<br />loam, very dark grayish brown (lOYR 3/2) when moist;
<br />I-2
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