LOCATION NOKHU                   CO

Established Series
Rev. AJC/JEB/KLS
11/2022

NOKHU SERIES

The Nokhu series consists of deep, well drained soils formed in thick, calcareous, medium to moderately fine textured materials derived from sedimentary, metamorphic, and igneous rocks. These soils are on gently to steeply sloping alluvial fans, mountainsides, and valley filling side slopes. Slopes are 2 to 50 percent. The mean annual precipitation is about 640 mm, and the mean annual air temperature is about 2 degrees C.

TAXONOMIC CLASS: Fine, smectitic Typic Glossocryalfs

TYPICAL PEDON: Nokhu loam - forest. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 5 cm; undecomposed organic material principally needles, bark, twigs, and leaves.

Oe--5 to 8 cm; partially decomposed organic material like that of the horizon above.

A--8 to 11 cm; dark gray (10YR 4/1) loam, black (10YR 2/1) moist; strong medium crumb structure; soft, very friable, slightly sticky, slightly plastic; neutral (pH 6.6); abrupt smooth boundary. (0 to 8 cm thick)

E--11 to 24 cm; light brownish gray (10YR 6/2) loam, grayish brown (10YR 5/2) moist; weak thin platy structure that parts to moderate fine and very fine granules; soft, very friable, slightly sticky, slightly plastic; neutral (ph 6.6); clear smooth boundary. (10 to 30 cm thick)

E/B--24 to 44 cm; mixed light brownish gray (10YR 6/2) and brown (10YR 5/3) loam, grayish brown (10YR 5/2) and brown (10YR 4/3) moist; weak fine subangular blocky structure that parts to moderate fine granules; slightly hard, very friable, slightly sticky, slightly plastic; the more clayey peds are very hard; thin wax-like patches on some faces of peds and wax-like coatings and fillings in root channels in the more clayey peds; this horizon consists of seams and nodules of clayey material like that of the underlying horizon embedded in a light color matrix like that of the overlying horizon; neutral (pH 6.6); gradual wavy boundary. (10 to 50 cm thick)

Bt--44 to 90 cm; brown (10YR 5/3) heavy clay loam, brown (10YR 4/3) moist; strong medium angular and subangular blocky structure; slightly hard, very friable, very sticky, very plastic; peds are extremely hard, very firm; continuous wax-like coatings on faces of peds in root channels and in pores; wax-like rims around the entrance to some pores; 5 percent gravel; neutral (pH 6.6); gradual wavy boundary. (20 to 110 cm thick)

BC--90 to 100 cm; brown (10YR 5/3) light clay loam, brown (10YR 4/3) moist; moderate medium and coarse subangular blocky structure; slightly hard, very friable, slightly sticky; slightly plastic; peds are extremely hard, firm; thin wax-like patches on some faces of peds and in some root channels and pores; 5 percent gravel; slightly alkaline (pH 7.8); clear wavy boundary. (5 to 25 cm thick)

C--100 to 136 cm; pale brown (10YR 6/3) light clay loam, yellowish brown (10YR 5/4) moist; massive; very hard, firm, slightly sticky, slightly plastic; 5 percent gravel; visible secondary calcium carbonate occurring as concretions and in thin seams and streaks; calcareous; moderately alkaline (pH 8.2)

TYPE LOCATION: Jackson County, Colorado; about 305 meters west and 30 meters south of NE corner Sec. 23, T. 7 N., R. 78 W.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 degrees C
Mean summer soil temperature--11 degrees C
Depth to uniformly calcareous material--43 to 140 cm
Base saturation--60 to 100 percent in all subhorizons of the argillic horizon
Depth to continuous horizons of visible secondary calcium carbonate accumulation--40 to 140 cm
Depth to the top of the argillic horizon--less than 60 cm
Depth to base of the argillic horizon--40 to 140 cm
Rock fragment content--0 to 35 percent in a major part of the solum and C horizon and are mainly 2 to 250 mm in diameter

A horizon, if present
Hue--5Y through 7.5YR
Value--4 or 5 dry, 2 or 3 moist
Chroma--1 through 3
Reaction--pH 6.1 to 7.8

E horizon
Hue--5Y through 7.5YR
Value--5 through 8 dry, 4 through 7 moist
Chroma--1 through 4
Reaction--pH 6.1 to 7.8

Bt horizon
Hue--5Y through 7.5YR
Value--5 through dry, 4 through 6 moist
Chroma--1 through 6
Texture--heavy clay loam or clay
Clay content--35 to 60 percent clay
Silt content--5 to 45 percent
Sand content--15 to 55 percent with more than 15 percent fine or coarser sand
Reaction--pH 6.1 to 7.8

C horizon
Hue--5Y through 7.5YR
Texture--loam, clay loam or sandy clay loam
Clay content--18 to 35 percent
Calcium carbonate equivalent--4 to 14 percent
Reaction--pH 7.9 to 9.0

COMPETING SERIES: These are the Asperson, Azarman, Bead, Chubbs, Contide, Cowdrey, Dell, Foxton, Gateway, Hatch, Lail, McVickers, Mikesell, Muggins, Wetterhorn, and Wickenson series. Asperson, Gateway, and Hatch soils have a paralithic contact at depths of less than 100 cm. Azarman and Cowdrey soils lack consistent horizons of visible secondary calcium carbonate accumulation above a depth of 100 cm and are noncalcareous throughout. Bead, Lail, and Muggins soils have hue of 5YR or redder. Chubbs, Foxton, McVickers, Wetterhorn, and Wickenson soils have a lithic contact at depths of less than 100 cm. Contide soils have sola thicker than 140 cm and have very think E and A/B horizons with the top of the argillic horizon occurring at depths greater than 60 cm. Dell soils lack consistent visible accumulation of secondary calcium carbonate above a depth of 100 cm. Mikesell soils have sola 100 to 165 cm thick that extend to bedrock and are noncalcareous throughout.

GEOGRAPHIC SETTING:
Landform--gently to steeply sloping alluvial fans, mountainsides, and valley filling side slopes
Elevation--2600 to 2900 meters
Slope--2 to 50 percent
Parent material--thick, calcareous, medium to moderately fine textured materials derived from sedimentary, metamorphic, and igneous rocks
Mean annual precipitation--640 mm with peak periods of precipitation in the spring and summer
Mean annual air temperature--2 degrees C
Frost-free period--20 to 30 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed

DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; slow permeability

USE AND VEGETATION: These soils are used as native pastureland, for recreation, and for timber production. Native vegetation is lodgepole pine, aspen, spruce, fir, and an understory of grasses and shrubs.

DISTRIBUTION AND EXTENT: Nokhu soils are moderately extensive in the mountainous areas of northcentral Colorado; MLRA 48A.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana

SERIES ESTABLISHED: Jackson County, Colorado, 1973

REMARKS: Converted to metric, updated formatting, and O horizons were updated to start at zero. Competing series section was not updated. 11/2022

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National Cooperative Soil Survey
U.S.A.