LOCATION ROCKWET CO
Established Series
Proposed LAN
10/2015
ROCKWET SERIES
The Rockwet series consists of very deep, moderately well drained soils that formed in clayey alluvium from irrigation water over silty alluvium derived from sedimentary deposits. Rockwet soils are on terraces and paleoterraces. Slopes range from 0 to 3 percent. Mean annual precipitation is about 305 millimeters (12 inches) and the mean annual temperature is about 11 degrees C (52 degrees F).
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Oxyaquic Calciustolls
TYPICAL PEDON: Rockwet silty clay loam, on a north facing, 1 percent slope in a cultivated field at an elevation of 1,294 meters (4,245 feet). (Colors are for dry soil unless otherwise noted.) When described on July 20, 2011 the soil was slightly moist from 0 to 30 centimeters, moist from 30 to 76 centimeters, and wet from 76 to 200 centimeters.
Ap1--0 to 18 cm (0 to 7 inches); dark grayish brown (10YR 4/2) silty clay loam, dark brown (10YR 3/3), moist; moderate fine granular structure; slightly hard, friable, moderately sticky and moderately plastic; strongly effervescent, 6 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt smooth boundary.
Ap2--18 to 30 centimeters (7 to 12 inches); dark grayish brown (10YR 4/2) silty clay loam, very dark grayish brown (10YR 3/2), moist; strong medium subangular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; strongly effervescent, 6 percent calcium carbonate equivalent; slightly alkaline (pH 7.8); abrupt smooth boundary. (combined thickness of the Ap horizons is 25 to 49 centimeters)
Bk--30 to 76 cm (12 to 30 inches); yellowish brown (10YR 5/4) silty clay loam, dark yellowish brown (10YR 4/4), moist; moderate fine subangular blocky structure; moderately hard, friable, slightly sticky and slightly plastic; 5 percent medium distinct threadlike carbonate masses in matrix; strongly effervescent, 10 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); gradual smooth boundary. (25 to 43 centimeters thick)
Bkg--76 to 102 cm (30 to 40 inches); pale brown (10YR 6/3) silty clay loam, brown (10YR 4/3), moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 10 percent medium distinct threadlike dark gray (10YR 4/1), moist, masses of reduced iron in matrix; 1 percent fine distinct spherical carbonate masses in matrix; violently effervescent, 18 percent calcium carbonate equivalent; moderately alkaline (pH 8.4); gradual smooth boundary. (0 to 36 centimeters thick)
Bg--102 to 200 cm (40 to 80 inches); yellowish brown (10YR 5/4) silt loam, brown (10YR 5/3), moist; weak coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; 15 percent medium, distinct, threadlike masses of reduced iron in matrix; strongly effervescent, 12 percent calcium carbonate equivalent; moderately alkaline (pH 8.0).
TYPE LOCATION: Otero County, Colorado; about 5.6 kilometers (3.5 miles) southeast of Manzanola, Colorado; about 183 meters (600 feet) west and 366 meters (1,200 feet) north of the southeast corner of sec. 5, T. 23 S., R. 57 W.; Manzanola, Colorado USGS quadrangle; UTM zone 13 604652 E 4214641 N; latitude 38 degrees, 4 minutes, 24.6 seconds N. and longitude 103 degrees, 48 minutes, 24.7 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil moisture control section is moist in some part March through May, intermittently moist June through September. Profile is continuously moist below 100 centimeters during the growing season.
Moisture regime: aridic moisture regime bordering on ustic.
Mean annual soil temperature: 10 to 13 degrees C. (50 to 55 degrees F.)
Depth to calcic horizon: 76 to 95 centimeters (30 to 37 inches)
Depth to redox depletions: 76 to 100 centimeters (30 to 40 inches)
Depth to endosaturation: 76 to 122 centimeters (30 to 48 inches) from April to September
Thickness of the mollic epipedon: 25 to 51 cm (10 to 20 inches)
Organic matter content: irregular decrease throughout the profile
Particle-size control section (weighted averages):
Clay content: 20 to 35 percent
Sand content: 5 to 20 percent
Rock fragment content: 0 to 5 percent gravel
Ap horizons have increases of clay and organic matter content due to prolonged irrigation, cultivation, and fertilization. Phosphorous content is not high enough for an anthropic epipedon.
Ap horizon(s):
Hue: 10YR
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3
Texture: silty clay loam, clay loam
Clay content: 27 to 35 percent
Calcium carbonate equivalent: 1 to 8 percent
EC (dS/m): 0 to 2
Sodium Adsorption Ratio: 0 to 2
Reaction: slightly alkaline to moderately alkaline
Bk horizon (s):
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 3 or 4
Texture: silty clay loam, silt loam
Clay content: 20 to 35 percent
Calcium carbonate equivalent: 5 to 25 percent
EC (dS/m): 0 to 4
Sodium Adsorption Ratio: 0 to 4
Reaction: moderately alkaline
Bkg horizon: (when present)
Hue: 7.5YR or 10YR
Value: 6 or 7 dry, 4 to 6 moist
Chroma: 1 to 3
Texture: silty clay loam, silt loam
Clay content: 20 to 35 percent
Calcium carbonate equivalent: 15 to 25 percent
EC (dS/m): 1 to 4
Sodium Adsorption Ratio: 1 to 6
Reaction: moderately alkaline to strongly alkaline
Bg horizon(s):
Hue: 7.5YR or 10YR
Value: 4 to 6 dry, 3 to 5 moist
Chroma: 1 to 4
Texture: silt loam, loam, fine sandy loam
Clay content: 15 to 27 percent
Rock fragment content: 0 to 15 percent
Calcium carbonate equivalent: 1 to 15 percent
EC (mmhos/m): 0 to 4
Gypsum content: 0 to 1 percent
Sodium Adsorption Ratio: 0 to 5
Reaction: slightly alkaline or moderately alkaline
COMPETING SERIES: There are presently no competing series.
GEOGRAPHIC SETTING:
Parent material: clayey alluvium from irrigation water over silty alluvium from sedimentary deposits
Landform: terraces, paleoterraces
Slopes: 0 to 3 percent
Elevation: 1,158 to 1,585 meters (3800 to 5200 feet)
Mean annual temperature: 10 to 12 degrees C. (50 to 54 degrees F.)
Mean annual precipitation: 256 to 356 centimeters (10 to 14 inches)
Wettest period: May through August
Driest period: December through February
Frost-free period: 130 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Kornman,
Numa,
Rocky Ford, and
Timpas series.
Kornman soils have a coarse-loamy control section, are well drained and are on terraces
Numa soils have a fine-loamy control section, are well drained and are on terraces and paleoterraces
Rocky Ford soils are well drained and are on terraces and paleoterraces
Timpas soils have a paralithic contact at depths of 100 to 152 centimeters (40 to 60 inches), are well drained and are on strath terraces
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: Moderately well drained
Saturated hydraulic conductivity: high or moderately high
Flooding: none to very rarely flooded; brief flooding during spring snowmelt.
USE AND VEGETATION: Used as irrigated cropland. Principal crops are alfalfa, corn, onions, and melons. Native vegetation is mainly blue grama, galleta, and four-wing saltbush. Loamy Plains R069XY006CO ecological site.
DISTRIBUTION AND EXTENT: Arkansas River Valley, Colorado; LRR G, MLRA 69 and 67B; The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Salina, Kansas
SERIES PROPOSED: Otero County, Colorado; Otero County soil survey area, 2013. The name is coined from a wet phase of the Rocky Ford series.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Series control section: The zone from 25 to 100 centimeters (10 to 40 inches).
Particle-size control section: The zone from 25 to 100 centimeters (10 to 40 inches). (Part of the Ap, the Bk and Bkg horizons)
Mollic epipedon: From 0 to 48 centimeters (0 to 19 inches). (Ap2 and Bw horizons)
Redoximorphic depletions: In the zone from 76 to 200 centimeters (30 to 80 inches. (Bkg and Bg horizons)
Endosaturation: The zone of saturation at 102 to 200 centimeters (40 to 79 inches). (Bg horizon)
LAN 9/2013 This soil was previously identified as a wet phase of the Rocky Ford series. This soil has a consistent water table during the growing season at depths within 76 to 122 centimeters of the surface.
Taxonomic Version: Eleventh Edition, 2010.
National Cooperative Soil Survey
U.S.A.