LOCATION CORNFLAT                NV

Established Series
REV: LJL/CAH/ET
04/2015

CORNFLAT SERIES

The Cornflat series consists of shallow, well drained soils that formed in marsh deposited alluvium derived from limestone. The Cornflat soils are on alluvial flats. Slopes range from 0 to 4 percent. The mean annual precipitation is about 125 millimeters and the mean annual air temperature is about 17 degrees C.

TAXONOMIC CLASS: Loamy, carbonatic, thermic Lithic Calciargids

TYPICAL PEDON: Cornflat gravelly very fine sandy loam, on a northwest facing (300 degrees), 1 percent slope at an elevation of 905 meters. When described on 6/25/2007 the soil was dry throughout. Colors are for dry soils unless otherwise noted. The soil surface is covered by 5 percent fine gravel, 10 percent medium and coarse gravel, 10 percent medium and coarse-sized indurated petrocalcic fragments.

A1--0 to 4 centimeters (0 to 2 inches); pale brown (10YR 6/3) gravelly very fine sandy loam, brown (10YR 4/3) moist; strong very thick platy structure; moderately hard, very friable, slightly sticky and nonplastic; few very fine roots; few fine tubular and common very fine vesicular pores; 10 percent fine and 7 percent medium, prominent, white (10YR 8/1), irregular,calcium carbonate nodules in the matrix, indurated, sharp boundaries; 3 percent medium and coarse gravel;; violently effervescent(33 percent calcium carbonate equivalence of the fine earth fraction); moderately alkaline (pH 8.4); abrupt smooth boundary.

A2--4 to 12 centimeters (2 to 5 inches); pale brown (10YR 6/3) gravelly fine sandy loam, dark yellowish brown (10YR 4/4) moist; moderate very thick platy parting to coarse subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine and few fine roots; few fine tubular and common very fine tubular pores; 8 percent fine and 15 percent medium, prominent, white (10YR 8/1), irregular,calcium carbonate nodules in the matrix, indurated, sharp boundaries; 2 percent fine gravel; violently effervescent (35 percent calcium carbonate equivalence of the fine earth fraction); moderately alkaline (pH 8.4); abrupt wavy boundary. (The combined thickness of the A horizons is 10 to 20 centimeters.)

Bt--12 to 19 centimeters (5 to 7 inches); pale brown (10YR 6/3) loam, dark yellowish brown (10YR 4/4) moist; moderate coarse subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; few fine tubular and common very fine tubular pores; 10 percent faint light brown (7.5YR 6/3), dry, clay films on ped faces and pores; 2 percent fine, prominent, white (10YR 8/1), irregular, calcium carbonate nodules in the matrix, indurated, sharp boundaries and 3 percent medium and coarse prominent, white (10YR 8/1), irregular, calcium carbonate nodules in the matrix, indurated, sharp boundaries; violently effervescent (38 percent calcium carbonate equivalence of the fine earth fraction); moderately alkaline (pH 8.2); abrupt wavy boundary. (5 to 15 centimeters thick)

Btk--19 to 40 centimeters (7 to 16 inches); very pale brown (10YR 7/3) very gravelly loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; few very fine tubular pores; 10 percent faint light brown (7.5YR 6/3), dry, clay films on ped faces and pores; 10 percent fine, prominent, white (10YR 8/1), irregular, calcium carbonate nodules in the matrix, indurated, sharp boundaries and 30 percent medium and coarse prominent, white (10YR 8/1), irregular, calcium carbonate nodules in the matrix, indurated, sharp boundaries; violently effervescent (51 percent calcium carbonate equivalence of the fine earth fraction); strongly alkaline (pH 8.6); very abrupt wavy boundary. (15 to 35 centimeters thick)

2Rkq--40 to 79 centimeters (16 to 31 inches); light gray (10YR 7/1), indurated travertine bedrock, light gray (10YR 7/2) moist; moderate very thick platy structure; very rigid; brittle; 1 percent prominent, brownish yellow (10YR 6/6), dry, silica on all faces of rock fragments; 5 percent fine, 5 percent medium and 5 percent coarse distinct, irregular, indurated, white (10YR 8/1), dry, calcium carbonate nodules with sharp boundaries around rock; violently effervescent; abrupt wavy boundary. (25 to 50 centimeters thick)

3Bkq--79 to 152 centimeters (31 to 60 inches); pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate coarse subangular blocky structure; moderately hard, very friable, slightly sticky and slightly plastic; few fine tubular and common very fine tubular pores; 1 percent prominent, brownish yellow (10YR 6/6), dry, silica on all faces of peds; 1 percent prominent, very dark grayish brown (10YR 3/2), dry, manganese coatings on faces of peds; 10 percent coarse prominent, irregular, noncemented, white (10YR 8/1), dry, calcium carbonate masses with clear boundaries in matrix; 1 percent fine gravel; violently effervescent (35 percent calcium carbonate equivalence of the fine earth fraction); strongly alkaline (pH 8.6).

TYPE LOCATION: Clark County, Nevada; approximately 430 meters north of the intersection of Alamo, Mormon Well, and Corn Creek roads, on Alamo Road, and 10 meters east, near Corn Creek Station, Nevada; about 225 meters north and 640 meters west of the southeast corner of Sec. 27, T. 17 S., R. 59 E.; USGS Corn Creek Springs, Nevada 7.5 minute quadrangle; 36 degrees, 26 minutes, 32.0 seconds north latitude and 115 degrees, 21 minutes, 29.1 seconds west longitude; UTM 11S 647157e 4034251n; (DATUM: NAD83).

RANGE IN CHARACTERISTICS:

Soil moisture control section: usually dry, moist in some part for short periods during winter and early spring. The soils have a Typic-Aridic moisture regime.

Soil temperature: 18 to 20 degrees C. (64 to 68 degrees F.)

Depth to argillic horizon: 10 to 20 centimeters.
Depth to calcic horizon: 18 to 25 centimeters.
Depth to lithic contact: 36 to 50 centimeters.


Control section
Rock fragments: averages 5 to 35 percent, ranges from 0 to 40 percent, dominantly indurated petrocalcic fragments.
Clay content: Averages 12 to 18 percent, ranges from 10 to 22 percent.
Calcium carbonate equivalence of the less than 20 millimeter fraction: 40 to 70 percent.

A horizon
Rock fragments: 15 to 35 percent, dominantly indurated petrocalcic fragments.
Calcium carbonate equivalence of the fine earth: 25 to 35 percent.

Bt horizon
Texture: loam or fine sandy loam.
Structure: weak or moderate.
Consistence: moderately hard or hard.
Rock fragments: 0 to 15 percent, dominantly indurated petrocalcic fragments.
Calcium carbonate equivalence of the fine earth: 35 to 45 percent.
Sodium Adsorption Ratio: 0 to 5.
Electrical conductivity: 0 to 2.

Btk horizon
Texture: loam or fine sandy loam.
Consistence: slightly hard or moderately hard.
Rock fragments: 15 to 40 percent, dominantly indurated petrocalcic fragments.
Reaction: moderately alkaline or strongly alkaline.
Calcium carbonate equivalence of the fine earth: 40 to 60 percent.
Sodium Adsorption Ratio: 0 to 5.
Electrical conductivity: 0 to 4.
Other features: 2 to 5 percent calcium carbonate clay.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: The Cornflat soils are on alluvial flats. Slopes range from 0 to 4 percent. These soils formed in marsh deposited alluvium derived from limestone. Elevation is 880 to 935 meters (2,890 to 3,070 feet). The climate is arid with hot, dry summers and warm, moist winters. The mean annual precipitation is 100 to 150 millimeters and the mean annual air temperature is 16 to 18 degrees C. The frost free season is 230 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Bluepoint and Threelakes soils. Bluepoint soils are on sand dunes and are very deep. Threelake soils are on fan remnants over lacustrine sediments and have a loamy-skeletal control section.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; very high runoff.The saturated hydraulic conductivity is moderately high above the bedrock, very low within the bedrock and moderately high below the bedrock.

USE AND VEGETATION: These soils are used for rangeland and wildlife habitat. The present vegetation is mainly shadscale saltbush, creosote bush, and burrobush.

DISTRIBUTION AND EXTENT: Mojave Desert of southern Nevada, U.S.A.; MLRA 30. These soils are not extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA

SERIES ESTABLISHED: Desert National Wildlife Refuge Area, Nevada, South Part; Clark County, Nevada, 2011. The name is coined from Corn Creek Station.

REMARKS: Diagnostic horizons and features recognized in the profile are:

Ochric epipedon - 0 to 12 centimeters (0 to 5 inches) (A1 and A2 horizons).
Argillic horizon - 12 to 40 centimeters (5 to 16 inches) (Bt and Btk horizons).
Calcic horizon - 19 to 40 centimeters (7 to 16 inches) (Btk horizon).
Lithic contact - 40 centimeters (16 inches) (2Rkq horizon).
Particle-size control section - 12 to 40 centimeters (5 to 16 inches) (Bt and Btk horizons).
Other features - The lower part of the profile was described from a nearby drainage way cut bank.

ADDITIONAL DATA: The USER PEDON ID is 07NV786014LL and was described on 6/25/2007.

Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 6/2011. ET

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National Cooperative Soil Survey
U.S.A.