LOCATION CAMAC NM COEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, mesic Typic Haplocambids
TYPICAL PEDON: Camac very cobbly fine sandy loam - on the riser of a high stream terrace sloping 43 percent to the west at 4,950 feet elevation--urban buildup area. (Colors are for dry soil unless otherwise noted. When described, the pedon was moist from 0 to 12 inches and dry below.)
A--0 to 3 inches; brown (10YR 5/3) very cobbly fine sandy loam, brown (10YR 4/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; few fine and many very fine roots; 30 percent gravel and 20 percent cobbles; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 5 inches thick)
Bw--3 to 12 inches; light yellowish brown (10YR 6/4) gravelly loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and common very fine roots; few very fine irregularly shaped pores; 10 percent gravel and 5 percent cobbles; strongly effervescent, secondary calcium carbonates segregated as few, thin coatings on undersides of gravel; moderately alkaline (pH 8.2); clear smooth boundary. (7 to 10 inches thick)
Bk--12 to 17 inches; pale brown (10YR 6/3) gravelly loam, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few fine and very fine roots; common very fine continuous tubular pores; 15 percent gravel and 5 percent cobbles; strongly effervescent, secondary calcium carbonates segregated as common, thin coatings on faces of peds and rock fragments; moderately alkaline (pH 8.4); abrupt wavy boundary. (4 to 7 inches thick)
2BCk--17 to 22 inches; grayish brown (10YR 5/2) clay loam, dark grayish brown (10YR 4/2) moist; weak coarse subangular blocky structure; hard, firm, sticky and plastic; common fine and very fine roots; common very fine continuous tubular pores; 5 percent gravel; strongly effervescent, secondary calcium carbonates segregated as few thin coatings on faces of peds and rock fragments; strongly alkaline (pH 8.6); clear wavy boundary. (3 to 9 inches thick)
2C--22 to 31 inches; gray (10YR 5/1) clay loam, dark gray (10YR 4/1) moist; platy rock structure; slightly hard, friable, sticky and plastic; common fine and very fine roots; few very fine horizontal pores; 60 percent soft siltstone fragments; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (3 to 9 inches thick)
2Cr--31 to 60 inches; gray (10YR 5/1) thinly interbedded siltstone and shale bedrock.
TYPE LOCATION: San Juan County, New Mexico; on the Navajo Indian Reservation within the town of Shiprock; 600 feet south and 150 feet west of the northeast corner of section 25, T. 30 N., R. 18 W.; Latitude 36 degrees 47 minutes 26 seconds N and Longitude 108 degrees 40 minutes 57 seconds W.
RANGE IN CHARACTERISTICS:
Soil Moisture - Typically, the soil moisture control section is intermittently moist in some part from July to October and December to March. The winter moisture precipitation peak is not as high as the summer peak. The soil is driest during May and June. Typic aridic moisture regime.
Soil Temperature - 54 to 57 degrees F.
Soil Depth - 20 to 40 inches to soft bedrock
Silicate clay content, control section weighted average - 18 to 35 percent
Depth to base of cambic horizon - 11 to 18 inches
Reaction - ranges from moderately alkaline in the surface to strongly alkaline in the subsoil and substratum
Calcium carbonate equivalence - 5 to 15 percent
A horizon-
Value: 5 or 6 dry or moist
Chroma: 3 or 4
Rock fragments: Total range is 35 to 60 percent
20 to 30 percent gravel
15 to 25 percent cobbles
0 to 5 percent stones
Salinity, mmhos/cm: 0 to 4
Bw horizon-
Value: 5 or 6 dry or moist
Chroma: 3 or 4
Texture: gravelly loam or gravelly fine sandy loam
Salinity, mmhos/cm: 0 to 4
Sodicity, SAR: 0 to 5
Rock fragments: Total range is 15 to 35 percent
10 to 20 percent gravel
5 to 10 percent cobbles
0 to 5 percent stones
Bk horizon-
Value: 5 or 6 dry
Chroma: 2 through 4
Texture: gravelly loam or gravelly sandy clay loam
Salinity, mmhos/cm: 2 to 4
Sodicity, SAR: 0 to 5
Rock fragments: Total range is 15 to 35 percent
10 to 20 percent gravel
5 to 10 percent cobbles
0 to 5 percent stones
Other features: some pedons have thin layers of silty clay loam
BC and C horizons-
Hue: 10YR or 2.5Y
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 1 through 3
Texture: loam or clay loam
Salinity, mmhos/cm: 4 to 8
Sodicity, SAR: 5 to 13
Rock fragments: 0 to 10 percent gravel, by volume
Other features: 10 to 60 percent soft, slakable siltstone fragments. Some pedons have up to 10 percent primary and secondary gypsum crystals.
COMPETING SERIES: There are no competitors.
GEOGRAPHIC SETTING: Camac soils are on risers of high stream terraces. They formed in alluvium derived from quartzite and residuum derived from Cretaceous siltstone and shale. Slopes are 15 to 60 percent. Elevation ranges from 4,600 to 5,100 feet. The mean annual precipitation is 5 to 8 inches with 35 to 60 percent falling as rain from high intensity thunderstorms between July and October. The mean annual temperature is 51 to 54 degrees F. The average frost-free period is 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackston, Fruitland, Kimbeto, Mesa, and Tocito soils. Blackston, Kimbeto and Mesa soils are very deep and occur on adjacent treads of high stream terraces. Fruitland and Tocito soils are very deep, lack diagnostic horizons and occur on fan terraces.
DRAINAGE AND PERMEABILITY: Well drained, rapid runoff; moderately slow permeability.
USE AND VEGETATION: Camac soils are used for livestock grazing and urban development. Present vegetation is galleta, Indian ricegrass, alkali sacaton, cheatgrass, shadscale, castle valley clover and small cacti.
DISTRIBUTION AND EXTENT: Camac soils are of moderate extent in the San Juan River valley, Navajo section of the Colorado Plateau in northwest New Mexico and southwest Colorado. LRR-D; MLRA 35.
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 3 inches. (A horizon)
Cambic horizon - The zone from 3 to about 12 inches. (Bw horizon)
Paralithic contact - The presence of soft sedimentary bedrock at about 31 inches. (2Cr horizon)
ADDITIONAL DATA: Salinity values were determined on three pedons including the type location, with a Wheatstone bridge. Calcium carbonate equivalence determined with a field volume calcimeter.
Classified according to Keys to Soil Taxonomy Ninth Edition, 2003.