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<br />Larkson Series
<br />The Larkson series consists of well-drained
<br />soils that formed in materials that weathered in
<br />place or that were transported from soft sediment-
<br />ary deposits nearby. These gently sloping to
<br />sloping soils are on upland hills and ridges in the
<br />southern part of the Area. Slopes are 3 to 9 per-
<br />cent. The vegetation is mainly ponderosa pine and
<br />a few Douglas-fir trees, with an un de rstory of
<br />Gambel oak and grass. Elevations are 7,000 to 8,000
<br />feeC. Annual precipitation is 17 to 19 inches.
<br />Mean annual soil temperature is 44° to 4fi° F., and
<br />the frost-free season is 115 to 120 days.
<br />In a representative profile the surface layer,
<br />about 4 inches thick, is dark grayish-brown fine
<br />sandy loam. It overlies a subsurface layer of pale-
<br />brown loam about 14 inches thick. The subsoil to a
<br />depth of 54 inches or more is brown and grayish-
<br />brown clay and clay loam.
<br />Larkson soils have slow permeability. Available
<br />water capacity is high. Plants can penetrate to a
<br />depth of 40 inches or more.
<br />All areas of Larkson soils are in native vegeta-
<br />tion and are used for grazing livestock, for wild-
<br />life habitat, and for recreation.
<br />Representative profile of a Larkson fine sandy
<br />loam, 200 feet north and 1,900 feet east of the
<br />southwest corner of sec. 14, T. 9 S., R. 67 VY.:
<br />01--1 inch to 0, partially decomposed organic
<br />material consisting mainly of pine needles,
<br />twigs, leaves, and bark.
<br />Al--0 to 4 inches, dark grayish-brown (lOYR 4/2)
<br />fine sandy loam, very dark brown (lOYR 2/2)
<br />when moist; moderate, medium, granular struc-
<br />ture; slightly hard, friable; slightly acid
<br />(pH 6.2); clear, smooth boundary.
<br />A21--4 to 9 inches, pale-brown (lOYR 6/3) loam, dark
<br />brown (lOYR 3/3) when moist; very weak, coarse
<br />prismatic structure; slightly hard, friable;
<br />slightly acid (pH 6.2); clear, smooth bound-
<br />ary.
<br />A22--9 to 13 inches, pale-brown (lOYR fi/3) loam,
<br />brown (lOYR S/3) when moist; massive; hard,
<br />friable; slightly acid (pH 6.4); clear, smooth
<br />boundary.
<br />AF,B--13 to 18 inches, pale-brown (lOYR 6/3) loam,
<br />brown (lOYR S/3) when moist; moderate, medium,
<br />subangular blocky structure; hard, .friable;
<br />nodules and seams of clayey material like that
<br />of the underlying horizon in a lighter colored
<br />matrix like that of the overlying horizon;
<br />slightly acid (pH fi.4); gradual, wavy boundary.
<br />B2t--18 to 30 inches, brown (7.SYR 5/4) clay, brown
<br />or dark brown (7.SYR 4/4) when moist; moder-
<br />ate, medium, prismatic structure parting to
<br />moderate, fine, angular blocky; extremely hard,
<br />very firm; thin continuous clay films on hori-
<br />zontal and vertical faces of peds; few slicken-
<br />sides; neutral (pH 7.0); gradual, wavy bound-
<br />ary.
<br />83--30 to S3 inches, grayish-brown (lOYR S/2) clay
<br />loam, dark grayish brown (lOYR 4/2) when
<br />r~
<br />~~
<br />moist; moderate, medium, prismatic structure
<br />parting to moderate, medium, subangular blocky;
<br />hard, firm, thin nearly continuous clay films
<br />on horizontal and vertical faces of peds; few
<br />slickensides; neutral (pH 7. 2).
<br />The dark-colored Al horizon ranges from 0 to 4
<br />inches in thickness and from loam to loamy sand in
<br />texture. The light-colored A2 horizon ranges from
<br />4 to 20 inches in thickness and from loam to loamy
<br />sand in texture. The 82t horizon ranges from 10 to
<br />36 inches or more in thickness. in places lime or
<br />shale is at a depth of more than 40 inches.
<br />Larkson fine sandy loam, 3 to 9 percent slopes
<br />(LaD).--This gently sloping to sloping soil is in
<br />wooded areas in the southern part of the Area. Most
<br />mapped areas are small.
<br />Included with this soil in mapping are small
<br />areas of Brus sett loam, 3 to 9 percent slopes, and
<br />Kettle loamy sand, S to 25 percent slopes. .A few
<br />rocks outcrop.
<br />Runoff is medium. The erosion hazard is slight.
<br />In most places the bottoms of drainageways are
<br />exposed rock.
<br />Areas of this soil are mainly used for livestock
<br />grazing, woodland products, wildlife habitat, and
<br />recreation. (Capability unit VIe-B)
<br />Alluvial Land
<br />Loamy alluvial land (Lo) is in swales or on flood
<br />plains in the northern part of the Area. Slopes are
<br />1 to 5 percent. These areas are long and narrow,
<br />and most of them are less than 40 acres in size.
<br />This highly stratified land type is dark colored
<br />to a depth of 30 inches or more. To a depth of 20
<br />inches this land is sandy loam to clay loam in tex-
<br />ture. Below that it is loamy sand to clay loam. A
<br />few gullies 4 to 20 feet deep are in areas once
<br />cultivated.
<br />Included with this land in mapping are small
<br />areas of Sampson loam, Bresser sandy loam, 1 to 3
<br />percent slopes, and Sandy alluvial land.
<br />This land is well drained. Permeability is mod-
<br />erate, and available water capacity is moderate to
<br />high. Runoff is medium. The erosion hazard is mod-
<br />erate to high. This land is flooded, usually
<br />every year, or at least once every 3 to S years.
<br />Effective rooting depth is more than 60 inches. This
<br />land has no beneficial seasonal high water table.
<br />All of the acreage is in native grass and is used
<br />for grazing livestock. (Capability unit VIw-1;
<br />Overflow range site)
<br />Loamy Alluvial Land, Dark Surface
<br />Loamy alluvial land, dark surface (Lu) is in
<br />swales or on flood plains in the northern part of the
<br />Area. Slopes are 0 to 4 percent. These areas are
<br />long and narrow, and most of them are less than 60
<br />acres in size.
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