LOCATION NUMA                    CO

Established Series
Rev. AJC/RVS/LAN
01/2014

NUMA SERIES

The Numa series consists of very deep, well drained soils that formed in clayey alluvium from sediment-rich irrigation water over loamy alluvium derived from mixed sources. Numa soils are on terraces and paleoterraces. Slopes range from 0 to 6 percent. The mean annual precipitation is about 305 millimeters (12 inches). The mean annual temperature is about 11 degrees C. (52 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Calciustolls

TYPICAL PEDON: Numa clay loam, on a northeast facing, 1 percent slope in a cultivated field at an elevation of 1,333 meters (4,375 feet). (Colors are for dry soil unless otherwise noted.) When described on December 9, 2010 the soil was moist from 0 to 200 centimeters.

Ap1--0 to 25 centimeters (0 to 10 inches); dark grayish brown (10YR 4/2) clay loam, very dark grayish brown (10YR 3/2) moist; strong fine angular blocky structure; moderately hard, firm, moderately sticky and moderately plastic; many fine roots throughout; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary.

Ap2--25 to 48 centimeters (10 to 19 inches); yellowish brown (10YR 5/4) clay loam, brown (10YR 4/3) moist; strong fine subangular blocky structure; very hard, firm, moderately sticky and moderately plastic; many fine roots throughout; slightly effervescent; slightly alkaline (pH 7.6); abrupt smooth boundary. (Combined thickness of the Ap horizons is 25 to 49 centimeters thick)

Bk1--48 to 87 centimeters (19 to 34 inches); pale brown (10YR 6/3) silt loam, yellowish brown (10YR 5/4) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; moderately hard, friable, slightly sticky and slightly plastic; common fine roots throughout; 10 percent medium, distinct, irregular carbonate masses in matrix; violently effervescent, 16 percent calcium carbonate equivalent; moderately alkaline (pH 8.0); clear smooth boundary.

Bk2--87 to 117 centimeters (34 to 46 inches); pale brown (10YR 6/3) loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 4 percent medium, distinct, spherical carbonate masses in matrix; violenty effervescent, 14 percent calcium carbonate equivalent; moderately alkaline (pH 8.2); gradual smooth boundary. (Combined thickness of the Bk1 and Bk2 horizons is 66 to 81 centimeters thick)

Bk3--117 to 200 centimeters (46 to 79 inches); yellowish brown (10YR 5/4) sandy loam, dark yellowish brown (10YR 4/4) moist; weak coarse subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; 1 percent fine, distinct, spherical carbonate masses in matrix; violently effervescent, 12 percent calcium carbonate equivalent; moderately alkaline (pH 8.2).

TYPE LOCATION: Otero County, Colorado; about 1.5 miles southwest of Fowler, Colorado; 152 meters (500 feet) west and 442 meters (1,450 feet) south of the northeast corner of Sec. 30, T. 22 S., R. 59 W. Sixth Principle Meridian; Hardesty Reservoir, Colorado, USGS topographic quadrangle; UTM zone 13 583908 E, 4218329 N; latitude 38 degrees, 6 minutes, 32 seconds N. and longitude 104 degrees, 2 minutes, 34.4 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Soil moisture: Moist in some part March through May and intermittently moist June through October. Driest December through February.
Moisture regime: aridic bordering on ustic
Mean annual soil temperature: 11 to 13 degrees C (52 to 55 degrees F.)
Depth to the calcic horizon: 25 to 100 centimeters (10 to 40 inches)

Particle size control section (weighted average)
Clay content: 20 to 30 percent
Silt content: 15 to 50 percent
Sand content: 25 to 65 percent
Rock fragments: 0 to 5 percent

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 horizons:
Hue: 10YR to 7.5YR
Value: 4 or 5 dry, 2 or 3 moist in the upper 25 centimeters, 3 or 4 moist below 25 centimeters
Chroma: 1 to 3
Texture: silty clay loam or clay loam
Clay content: 27 to 35 percent
Calcium carbonate equivalent: 1 to 5 percent
Reaction: slightly to moderately alkaline

Bw horizons (where present):
Hue: 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 4
Texture: loam, silt loam
Clay content: 18 to 27 percent
Sand content: 25 to 55 percent
Rock fragments: (if needed)
Calcium carbonate equivalent: 5 to 10 percent
Reaction: slightly or moderately alkaline

Bk1 and Bk2 horizons:
Hue: 10YR or 7.5YR
Value: 6 through 8 dry, 4 through 6 moist
Chroma: 3 or 4
Texture: loam,silt loam, fine sandy loam, or sandy loam
Clay content: 12 to 27 percent
Rock fragment content: 0 to 5 percent
Calcium carbonate equivalent: 5 to 35 percent with at least one horizon with 15 percent or more
Exchangeable sodium: 0 to 4 percent
Electrical conductivity: 0.1 to 2 dS/m
Gypsum: 0 to 1 percent
Sodium Adsorption Ratio: 0.1 to 6
Reaction: slightly alkaline to strongly alkaline

Bk3 horizon:
Hue: 10YR or 7.5YR
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 3 through 6
Texture: sandy loam, fine sandy loam, loam, or silt loam
Clay content: 10 to 27 percent
Rock fragment content: 0 to 15 percent
Calcium carbonate equivalent: 5 to 20 percent
Gypsum content: 0 to 1 percent
Electrical conductivity: 0.5 to 2 dS/m
Exchangeable sodium: 2 to 6 percent
Sodium Adsorption Ratio: 1 to 4
Reaction: slightly alkaline or moderately alkaline

C horizons (where present):
Hue: 7.5YR or 10YR
Value: 5 through 7 dry, 4 through 6 moist
Chroma: 3 through 6
Texture: fine sandy loam, sandy loam, loam, sandy clay loam
Clay content: 10 to 27 percent
Rock fragments: 0 to 5 percent
Calcium carbonate equivalent: 5 to 20 percent
Electrical conductivity: 1 to 2 dS/m
Exchangeable sodium: 2 to 6 percent
Reaction: slightly alkaline or moderately alkaline

COMPETING SERIES: These are the Dioxice, Escabosa, Jonale, Section, and Suglo series.
Dioxice soils: do not have increased clay and organic matter in the Ap horizons from sediment-rich irrigation water and have gravel fragments consisting of petrocalcic material.
Escabosa soils: have a lithic contact at depths of 51 to 100 cm (20 to 40 inches.
Hovenweep soils: have a paralithic contact at depths of 51 to 100 cm (20 to 40 inches).
Jonale soils: do not have increased clay and organic matter in the Ap horizons from sediment-rich irrigation water. It is typically driest in May and June.
Section soils: do not have increased clay and organic matter in the Ap horizons from sediment-rich irrigation water and have a soil moisture control section that is dry in May and June.
Suglo soils: average 15 to 35 percent rock fragments in the control section.

GEOGRAPHIC SETTING:
Parent material: clayey alluvium from irrigation water over loamy alluvium derived from mixed sources.
Landform: Terraces and paleoterraces
Slopes: 0 to 6 percent or more
Elevation:
Mean annual temperature: 10 to 12 degrees C (50 to 54 degrees F.)
Mean annual precipitation: 254 to 356 millimeters (10 to 14 inches)
Precipitation pattern:
Peak period: May through August
Driest period: December through February
Frost free season: 130 to 170 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cascajo, Kornman, Manveland Rocky Ford soils. They all formed on terraces and paleoterraces.
Kornman soils: have a coarse-loamy control section and occur on terraces
Manvel soils: lack a mollic epipedon and have a fine-silty control section. They occur on the upper third of paleoterraces.
Rocky Ford soils: have a fine-silty control section and occur on terraces and paleoterraces.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage: well drained
Saturated Hydraulic Conductivity: moderately high to high
Flooding: Non-flooded to very rare, brief flooding during Spring snowmelt

USE AND VEGETATION: Used as irrigated cropland.
Principal irrigated crops are alfalfa, small grain, corn, sorghum, truck crops, and melons. Native vegetation is mainly blue grama, galleta, and western wheatgrass. (ESD:)

DISTRIBUTION AND EXTENT: The Arkansas Valley, Colorado, LRR G, MLRA 67B and 69. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado

SERIES ESTABLISHED: Prowers County, Colorado, 1963.

REMARKS: Diagnostic horizon and features recognized in this pedon are:
Series control section: 0 to 200 centimeters
Particle size control section: 25 to 100 centimeters (10 to 40 inches)
Mollic epipedon: 0 to 25 centimeters (0 to 10 inches). (Ap1 horizon)
Calcic horizon: 48 to 87 centimeters (19 to 34 inches). (Bk1 horizon)

The assignment of the cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.

LAN 3/2013 The previous classification of Ustic Haplocalcids became obsolete after a field project indicated that these soils had mollic epipedons. Based on this project the type location was moved from Prowers County, Colorado to Otero County, Colorado and changes the Taxonomic class to Fine-loamy, mixed, superactive, mesic Aridic Calciustolls.

Last updated on 10/2013.

Modified format by LRM in 7/2006 to include metric conversion and change permeability to saturated hydraulic conductivity.
Updated horizon suffix changing Ca to k. JCR

Taxonomic Version: Eleventh Edition, 2010

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National Cooperative Soil Survey
U.S.A.