LOCATION CAPTOM NMEstablished Series
TAXONOMIC CLASS: Loamy, mixed, active, frigid Arenic Haplustalfs
TYPICAL PEDON: Captom very flaggy loamy sand -- on a slightly convex backslope sloping 56 percent to the east at 8,960 feet elevation - forest. (Colors are for dry soil unless otherwise noted. When described, the soil was moist from 0 to 8 inches and dry from 8 to 58 inches.) The surface is covered with 2 inches of oak leaves, pine needles, and other forest litter.
A-- 0 to 8 inches; brown (7.5YR 4/2) very flaggy loamy sand, dark brown (7.5YR 3/2) moist; moderate medium granular structure; soft, very friable, slightly sticky and nonplastic; few medium and common fine and very fine roots; few very fine irregular pores; 5 percent pebbles, 15 percent channers and 20 percent flagstones; neutral (pH 6.6); clear smooth boundary. (5 to 9 inches thick)
E-- 8 to 13 inches; pinkish gray (7.5YR 6/2) very channery loamy sand, brown (7.5YR 4/2) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; few coarse and common very fine and medium roots; few fine and very fine irregular pores; 10 percent pebbles, 25 percent channers, and 5 percent flagstones; neutral (pH 6.6); clear wavy boundary. (5 to 17 inches thick)
E/Bt-- 13 to 32 inches; light brown (7.5YR 6/4) channery loamy sand; brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common very fine and fine roots; few fine and very fine irregular pores; common bleached sand grains (skeletans) on faces of peds; clay bridging on rock fragments and on sand grains in few thin lamellae less than 1 cm thick(Bt part); 5 percent pebbles, 20 percent channers, and 5 percent flagstones; neutral (pH 6.8); clear wavy boundary. (4 to 21 inches thick)
2Bt1-- 32 to 43 inches; reddish brown (5YR 5/4) sandy clay loam; yellowish red (5YR 4/6) moist; moderate coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine and few very fine and coarse roots; few fine and very fine tubular pores; common thin clay films on faces of peds and lining pores; 5 percent pebbles; neutral (pH 6.8); clear smooth boundary. (11 to 24 inches thick)
2Bt2-- 43 to 58 inches; reddish yellow (7.5YR 6/6) sandy loam, strong brown (7.5YR 5/6) moist; weak coarse subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; few very fine and medium roots; few very fine tubular pores; few thin lamellae less than 1 cm thick, common thin clay films bridging sand grains; neutral (pH 6.8); clear smooth boundary. (5 to 21 inches thick)
2Cr-- 58 inches; soft sandstone bedrock
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation about 6 miles southwest of Toadlena; 2,350 feet west and 500 feet north of the southeast corner of section 2, T.22N., R.20W.; Latitude 36 degrees 10 minutes 2 seconds North, and Longitude 108 degrees 56 minutes 35 seconds West.
RANGE IN CHARACTERISTICS:
Soil moisture - Typically, the soil moisture control section (SMCS) is moist in all parts from January to May and intermittently moist in some part from June to December. The SMCS is moist in all parts greater than 40 percent of the time (cumulative), when the soil temperature at 20 inches is 41 degrees F or higher. Typic ustic moisture regime
Soil temperature - 42 to 44 degrees F.
Soil depth - 40 to 60 inches to soft bedrock
Depth to albic horizon - 5 to 9 inches
Depth to lithologic discontinuity and loamy subsoil horizon - 20 to 40 inches
Reaction - slightly acid to neutral
Particle-size control section - clay content: 18 to 27 percent by weighted average
Rock fragments - 0 to 15 percent in control section
A horizon
Hue: 7.5YR or 10YR
Value: 3 through 5 dry, 2 or 3 moist
Organic carbon content: 1 to 2 percent
Rock fragments: Total range is 35 to 60 percent
5 to 10 percent pebbles
10 to 15 percent channers
20 to 30 percent flagstones (5 to 10% >10")
0 to 5 percent cobbles
E horizon
Hue: 7.5YR or 10YR
Value: 5 through 7 dry, 4 or 5 moist
Chroma: 2 or 3
Organic carbon content: less than 0.5 percent
Texture: very channery loamy sand, very channery loamy fine sand
Rock fragments: Total range is 35 to 60 percent
5 to 10 percent pebbles
20 to 35 percent channers (5 to 10% >3")
10 to 15 percent flagstones (0 to 5% >10")
E/Bt horizon
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 through 4
Organic carbon content: less than 0.5 percent
Texture: channery loamy sand or channery loamy fine sand
Rock fragments: Total range is 15 to 35 percent
5 to 10 percent pebbles
10 to 20 percent channers (0 to 5 % >3")
0 to 5 percent flagstones
2Bt1 horizon
Hue: 5YR or 7.5YR
Value: 5 or 6 dry
Chroma: 4 through 6
Organic carbon content: less than 0.5 percent
Texture: sandy clay loam or sandy loam
Clay content: 18 to 27 percent
Rock fragments: Total range is 0 to 15 percent
0 to 5 percent pebbles
0 to 5 percent channers
0 to 5 percent flagstones
Other features: 0 to 15 percent soft sandstone fragments
present in some pedons
2Bt2 horizon
Hue: 5YR or 7.5YR
Value: 5 through 7 dry, 4 or 5 moist
Chroma: 4 through 6
Organic carbon content: less than 0.5 percent
Texture: sandy loam or fine sandy loam
Clay content: 15 to 20 percent
Other features: 10 to 25 percent soft sandstone fragments
present in some pedons
COMPETING SERIES: There are no competitors.
GEOGRAPHIC SETTING: Captom soils are on backslopes of high plateaus, mesas, and structural benches. They formed in colluvium and residuum derived from Tertiary sandstone. Slopes range from 35 to 60 percent. Elevation ranges from 8,500 to 9,200 feet. The mean annual precipitation is 20 to 22 inches with more than 50 percent falling as snow from winter storms. The mean annual temperature is 40 to 42 degrees F. The average frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Akhoni, Berland, Bikeyah, Klizhin and Retaw soils. Akhoni soils are shallow to sandstone and occur on adjacent broad summits. Berland soils are very shallow to sandstone and occur on non-wooded knolls and benches. Bikeyah soils lack argillic horizons, are non-wooded and occur on toeslopes. Klizhin soils lack argillic horizons and occur on footslopes below Captom soils. Retaw soils are very poorly drained and have standing water on the surface.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; rapid permeability in the epipedon and moderate in the subsoil.
USE AND VEGETATION: Captom soils are used for timber production and limited livestock grazing. Present vegetation is ponderosa pine with an understory of Gambel oak, Kentucky bluegrass, bottlebrush squirreltail, earth sedge and Oregon grape.
DISTRIBUTION AND EXTENT: Captom soils are of small extent on the Defiance Upwarp-Chuska Mountains portion of the Colorado Plateau Province in northwest New Mexico and northeast Arizona. LRR-D; MLRA 39.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona
SERIES ESTABLISHED: Shiprock Area, Parts of San Juan County, New Mexico and Apache County, Arizona; 1993.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to a depth of about 32 inches. (A, E, and E/Bt horizons)
Albic horizon - The zone from 8 to 13 inches. (E
horizon)
Arenic subgroup - The presence of 32 inches of soil material coarser than loamy very fine sand overlying the argillic horizon. (A, E, and E/Bt horizons)
Argillic horizon - The zone from 32 to 58 inches. (2Bt1 and 2Bt2 horizons)
Paralithic contact - The presence of soft sandstone bedrock at 58 inches.
Keys to Soil Taxonomy - Soils classified according to the Eighth Edition, 1998.
ADDITIONAL DATA: Organic carbon values are estimated.
-Annual Pattern of Soil-Water States- -----------------------------------------------------------
Depth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
(in)
0-8 f f f m m d d d d m m f
8-13 f f m m m d d m m m m m
13-32 m m m w m m d d d d m m
32-43 d d d w m m d d d d d d
43-58 d d d m m m m d d d d d ------------------------------------------------------------
f: frozen more than half of the month
w: wet more than half of the month
m: moist more than half of the month
d: dry more than half of the month
Information gathered from: Estimates and field notes