LOCATION MONTROSE CO

Established Series
IRD CRP/JCK
04/2019

MONTROSE SERIES

The Montrose series consists of very deep, well drained soils that formed in alluvium or slope alluvium derived from calcareous sandstone and shale. Montrose soils are on stream terraces, strath terraces and eroded fan remnants. Slopes are 0 to 12 percent. Mean annual precipitation is about 203 mm, and mean annual air temperature is about 11 degrees C.

TAXONOMIC CLASS: Fine, mixed, active, mesic Typic Haplargids

TYPICAL PEDON: Montrose silty clay loam in irrigated corn at an elevation of 1,667 meters. (Colors are for dry soil unless otherwise noted.)

Ap--0 to 10 cm; pale brown (10YR 6/3) silty clay loam, yellowish brown (10YR 5/4) moist; weak fine and medium angular blocky structure parting to moderate fine and medium granular; hard, friable, very sticky and very plastic; few fine roots; strongly effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary. (10 to 32 cm thick)

Bt--10 to 33 cm; pale brown (10YR 6/3) silty clay, brown (10YR 5/3) moist; weak coarse subangular blocky structure parting to weak fine and medium subangular blocky; hard, friable, very sticky and very plastic; few fine roots; few fine and medium tubular pores; 5 percent distinct clay films on faces of peds and on surfaces along pores; strongly effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary. (12 to 40 cm thick)

Btz--33 to 91 cm; light yellowish brown (2.5Y 6/3) silty clay, light olive brown (2.5Y 5/3) moist; weak medium and coarse subangular blocky structure; hard, friable, very sticky and very plastic; few fine roots; few fine tubular pores; 10 percent distinct clay films on all ped faces; 2 percent fine threadlike salt masses in the matrix; strongly effervescent; moderately alkaline (pH 8.0); gradual wavy boundary. (0 to 60 cm thick)

C--91 to 165 cm; light yellowish brown (2.5Y 6/3) silty clay loam, olive brown (2.5Y 4/3) moist; massive; hard, friable, moderately sticky and very plastic; strongly effervescent; moderately alkaline (pH 8.0).

TYPE LOCATION: Montrose County, CO; located about 152 meters east and 412 meters south of the northwest corner of sec. 19, T. 50 N, R. 9 W; Olathe USGS quad; lat. 38 degrees 35 minutes 13 seconds N and long. 107 degrees 55 minutes 38 seconds W. NAD 1927.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 11 to 14 degrees C
Particle-size control section (weighted average):
Clay content - 35 to 50 percent
Rock fragments - 0 to 5 percent gravel

A horizon
Hue: 10YR or 2.5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2, 3 or 4 dry or moist
Texture: silty clay loam, clay loam, clay or silty clay
Clay content: 28 to 45 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 0 to 15 percent
Gypsum: 0 to 5 percent
Electrical conductivity: 0 to 4 mmhos/cm
Sodium adsorption ratio: 0 to 4
Reaction: 7.4 to 8.6

Btz horizon
Hue: 10YR or 2.5Y
Value: 5, 6, or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4 dry or moist
Texture: silty clay, clay, silty clay loam or clay loam
Clay content: 35 to 50 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 5 to 15 percent
Gypsum: 0 to 4 percent
Electrical conductivity: 2 to 8 mmhos/cm
Sodium adsorption ratio: 2 to 8
Reaction: 7.8 to 8.6

C horizon
Hue: 10YR or 2.5Y
Value: 5, 6 or 7 dry; 4 or 5 moist
Chroma: 2, 3, or 4 dry or moist
Texture: silty clay loam, clay loam, silty clay or clay
Clay content: 20 to 50 percent
Rock fragments: 0 to 5 percent gravel
Calcium carbonate equivalent: 0 to 15 percent
Gypsum: 0 to 4 percent
Electrical conductivity: 2 to 8 mmhos/cm
Sodium adsorption ratio: 4 to 13
Reaction: 7.8 to 8.8

Some pedons have a BC above the C horizon.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Landform - stream terraces, strath terraces and eroded fan remnants
Elevation - 1,372 to 1,768 meters
Slope - 0 to 12 percent
Parent material - alluvium or slope alluvium derived from calcareous sandstone and shale
Mean annual air temperature - 10 to 12.8 degrees C
Mean annual precipitation - 152 to 229 mm
Frost-free period - 140 to 180 days
Precipitation pattern - slight increase in spring; significant increase in late summer

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Fruita, Fruitland and Mesa soils.

DRAINAGE AND PERMEABILITY: Well drained; moderately slow to slow permeability.

USE AND VEGETATION: Montrose soils are primarily used for irrigated cropland and hayland. Native vegetation is shadscale saltbush, squirreltail, bud sagebrush, winterfat, saline wildrye and Indian ricegrass.

DISTRIBUTION AND EXTENT: Montrose soils are of small extent in southwest Colorado. MLRA 34B.

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

SERIES ESTABLISHED: Montrose County, Colorado - Ridgway Area, Colorado, Parts of Delta, Gunnison, Montrose, and Ouray Counties, 2019.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 10 cm Ap horizon)
Argillic horizon - from 10 to 91 cm (Bt and Btz horizons)
Secondary soluble salt accumulation - from 33 to 91 cm (Btz horizon)
Particle-size control section - from 10 to 60 cm (Bt and part of Btz horizon)

Montrose soils have a mesic temperature regime and an aridic moisture regime.

National Cooperative Soil Survey
U.S.A.