LOCATION CORUM CA
Tentative Series
Rev. PWB-MAV
04/2015
CORUM SERIES
The Corum series consists of moderately deep, well drained soils on fan terraces along the margins of Rodgers Dry Lake. These soils formed in granitic fan alluvium that has overwashed material weathered from granitic rock. Slopes range from 0 to 5 percent. The average annual precipitation is 4 to 5 inches, and the mean annual temperature is 60 to 64 degrees F.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Typic Natrargids
TYPICAL PEDON: Corum sandy loam, on an east-facing slope of 1.5 percent, under allscale saltbush, schismus, and filaree at an elevation of 2,280 feet. (When described on July 19, 1988, the soil was dry throughout; Colors are for dry soil unless otherwise stated). There are 35 percent coarse fragments (2 to 15 mm in diameter) on the surface.
A1--0 to 2 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many; many very fine interstitial pores; 12 percent pebbles (2 to 15 mm in diameter); very slightly effervescent disseminated lime; slightly alkaline (pH 7.8); abrupt smooth boundary.
A2--2 to 7 inches; pale brown (10YR 6/3) sandy loam, dark brown (10YR 4/3) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine roots; common very fine interstitial and few very fine tubular pores; 5 percent pebbles (2 to 8 mm in diameter); slightly alkaline (pH 7.8); clear smooth boundary.
A3--7 to 12 inches; pale brown (10YR 6/3) sandy loam, dark brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and few fine and medium roots; common very fine interstitial and few very fine tubular pores; 5 percent pebbles (2 to 8 mm in diameter); moderately alkaline (pH 8.4); abrupt smooth boundary. (Combined thickness of the A horizons is 4 to 15 inches)
2Btn--12 to 15 inches; light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; weak coarse columnar structure; hard, firm, sticky and plastic; few very fine, fine, and medium roots; common very fine and few fine tubular pores; common thin clay films in bridges between mineral grains and few thin clay films on peds; 10 percent pebbles (2 to 8 mm in diameter); very slightly effervescent disseminated lime; strongly alkaline (pH 8.8); clear smooth boundary. (3 to 7 inches thick)
2Bkn--15 to 27 inches; light yellowish brown (10YR 6/4) sandy loam, dark yellowish brown (10YR 4/4) moist; massive; hard, friable, slightly sticky and slightly plastic; few very fine, fine, and medium roots; common very fine and few fine and medium tubular pores; 8 percent pebbles (2 to 8 mm in diameter); violently effervescent disseminated lime and segregated as many fine and medium soft masses; very strongly alkaline (pH 9.2); abrupt smooth boundary. (8 to 16 inches thick)
3Btknb--27 to 34 inches; light yellowish brown (10YR 6/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; massive; hard, friable, sticky and plastic; few very fine, fine, and medium roots; common very fine and few fine tubular pores; few thin and moderately thick clay films in bridges between mineral grains and in pores; 8 percent pebbles (2 to 8 mm in diameter); violently effervescent disseminated lime and segregated as common fine soft masses; strongly alkaline (pH 8.6); clear wavy boundary. (3 to 10 inches thick)
3Cr--34 to 51 inches; soft, strongly weathered granitic rock; clear wavy boundary. (1 to 20 inches thick)
3R--51 inches; hard granitic rock.
TYPE LOCATION: Kern County, California; about 2 miles north of Edwards AFB headquarters; 1375 feet west and 200 feet south of the northeast corner of Sec. 24, T. 10 N., R. 10 W., Edwards quadrangle., SBBM.
RANGE IN CHARACTERISTICS: Weathered granitic rock is at a depth of 20 to 40 inches. The mean annual soil temperature is 63 to 72 degrees F. The soil temperature is below 47 degrees F. from about December 15 to February 20, and is usually never below 41 degrees F. The soil between the depths of 4 and 12 inches is dry throughout for 275 to 310 days from about March 1 to December 15. It is moist throughout for 10 to 50 days from about January 1 to March 1 and is moist in some or all parts for 55 to 90 consecutive days from about December 15 to March 1 when the soil is above 47.
The A horizon has dry colors of 10YR 5/3, 5/4, 6/3 or 6/4. Moist color is 10YR 3/3, 4/3 or 4/4. It has 6 to 15 percent clay and 0 to 15 percent gravel. It is noneffervescent or slightly effervescent. Reaction is mildly alkaline or moderately alkaline.
The 2Btn horizon has dry colors of 10YR 6/3 or 6/4. Moist colors are 10YR 4/3 or 4/4. It is sandy loam or sandy clay loam with 16 to 25 percent clay, but averages 18 to 25 percent. It has 5 to 15 percent gravel.
The 2Bkn horizon has dry colors of 10YR 6/3 or 6/4. Moist colors are 10YR 4/3 or 4/4. It is loamy sand or sandy loam with 6 to 15 percent clay and 5 to 15 percent gravel. It has 5 to 15 percent calcium carbonate equivalent. Reaction is strongly alkaline or very strongly alkaline.
The buried 3Btknb horizon has dry colors of 10YR 6/3, 6/4; or 7.5YR 6/4. Moist colors are 10YR 4/3, 4/4; or 7.5YR 4/4. It has 20 to 30 percent clay and 5 to 15 percent gravel. Reaction is strongly alkaline or very strongly alkaline.
COMPETING SERIES: These are the
Casaga (T),
Garces,
Gothard,
Leuhman (T), Nomie (T),
Norob, and
Polvadero (T) series. None of these soils have a lithic or paralithic contact within 60 inches of the surface.
GEOGRAPHIC SETTING: Corum soils are on fan terraces. Slopes are 0 to 5 percent. The soils formed in granitic fan alluvium that has overwashed material weathered from granitic rock. Elevations are 2,270 to 2,300 feet. The climate is arid with hot, dry summers and cool, slightly moist winters. The mean annual precipitation is 4 to 5 inches. The mean annual temperature is 60 to 64 degrees F. Mean July temperature is about 83 degrees F., and mean January temperature is about 44 degrees F. The frost-free season is 200 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Eclipse,
Machone (T),
Neuralia,
Randsburg, and
Wherry soils. Eclipse soils are on adjacent beach terraces and are very deep and sandy. Machone soils are on adjacent hills, are coarse-loamy, and do not have a natric horizon. Neuralia soils are on similar landforms, but are very deep and do not have a natric horizon. Randsburg soils are on adjacent hills, are coarse-loamy, and are shallow to a paralithic contact. Wherry soils are in adjacent basins, are fine textured, and do not have a natric horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderately slow permeability. The soils are subject to rare flooding.
USE AND VEGETATION: Corum soils are used primarily for building sites, aircraft taxiways, streets, and parking areas. Vegetation in undeveloped areas is dominantly allscale saltbush, schismus, filaree, red brome, and a variety of annual forbs.
DISTRIBUTION AND EXTENT: Mojave Desert of California. The series is not extensive in MLRA 30.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES PROPOSED: Kern County, California, 1988. The name is coined.
REMARKS: These soils may have some lacustrine influence, but are dominantly from granitic fan alluvium derived from hills.
Diagnostic horizons and features recognized in this profile are:
1. Ochric epipedon -- 0 to 12 inches (A1, A2, A3)
1.1 Organic carbon assumed to be less than 0.6 percent based on laboratory analysis of similar soils in surrounding surveys.
1.2 Moist color of 10YR 4/3.
2. Natric horizon -- 12 to 15 inches (2Btn).
2.1 Weak coarse columnar structure.
2.2 Sandy clay loam texture with an increase of 10 percent clay content from the A horizon based on field estimates.
2.3 Common thin clay films bridging mineral grains and on ped faces.
2.4 It is 3 inches thick (minimum thickness for natric horizon).
2.5 SAR is assumed to be over 13 within 40 cm of its upper boundary based on the pH of 8.8 in this horizon and a pH of 9.2 in the underlying 2Bkn horizon. Reference samples were sent to the Lincoln Lab to confirm assumptions.
ADDITIONAL DATA:
1. Typic subgroup: Meets all requirements of the Typic subgroup.
2. TEMPERATURE REGIME -- Thermic. Mean annual soil temperature is 63 to 72 degrees F. Based on soil temperature data from surrounding soil surveys and preliminary field measurements.
3. MINERALOGY -- Mixed; no evidence to support any other.
4. PARTICLE SIZE CLASS -- Fine-loamy. The 12- to 15-inch particle-size control section averages 20 percent clay based on field estimates.
5. MOISTURE REGIME - Aridic. Based on soil moisture data from surrounding soil surveys.
The graph below is a representation of the moisture control section.
Months: J F M A M J J A S O N D DAYS:
|...|...|...|...|...|...|...|...|...|...|...|...|
DRY
THROUGHOUT |...|...<-------------290 days---------------->.|
MOIST IN SOME
OR ALL PART -75 days>...|...|...|...|...|...|...|...|...|.<-
EXCEEDS 41
DEGREES F. <-------------------365 days-------------------->
EXCEEDS 47
DEGREES F. |...|..<--------------303 days---------------->.|
Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 9/2006. ET
National Cooperative Soil Survey
U.S.A.