LOCATION EXEL CA

Established Series
Rev. WBS/TDC/JJJ
01/2023

EXEL SERIES

The Exel series is a member of the fine-loamy, mixed, mesic family of Xerollic Durargids. Typically, Exel soils have light brownish gray and brown loam slightly acid A horizons; reddish brown gravelly clay loam B2t horizons over an indurated duripan at a depth of 35 inches. Stratified cemented pebbles and cobbles occur at depth of 43 inches.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Argidurids

TYPIFYING PEDON: Exel loam - rangeland (Colors are for dry soil unless otherwise stated.)

A1--0 to 5 inches; light brownish gray (10YR 6/2) loam, dark brown (10YR 3/3) moist; moderate medium and coarse granular structure; soft, very friable, slightly sticky, slightly plastic; many very fine roots; many very fine interstitial ant few very fine tubular pores; slightly acid (pH 6.5); clear smooth boundary. (4 to 6 inches thick)

A2--5 to 11 inches; brown (10YR 5/3) heavy loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; slightly hard, friable, sticky, slightly plastic; common very fine roots; common very fine interstitial and tubular pores; few thin clay films as bridges between mineral grains; slightly acid (pH 6.5); clear wavy boundary. (4 to 7 inches thick)

Bt1--11 to 17 inches; brown (7.5YR 5/2) cobbly clay loam, dark brown (7.5YR 3/2) moist; moderate medium and coarse angular blocky structure; hard, friable, sticky, plastic; few very fine roots; common very fine interstitial and tubular pores; many moderately thick clay films on peds and common thin clay films in pores and as bridges; slightly acid (pH 6.5); clear wavy boundary. (4 to 7 inches thick)

Bt2--17 to 25 inches; reddish brown (5YR 4/4) very cobbly clay loam, dark reddish brown (5YR 3/4) moist; dark reddish gray (5YR 4/2) coating on peds, dark reddish brown (5YR 3/3) moist; strong medium angular blocky structure; very hard, firm, sticky, very fine tubular pores; many thick clay films on peds, common thick clay films in pores and as bridges; 15 percent pebbles and 40 percent cobbles; slightly acid (pH 6.5); gradual irregular boundary. (6 to 10 inches thick)

Bt3--25 to 30 inches; reddish brown (5YR 4/3) gravelly clay loam, dark reddish brown (5YR 3/3) moist; moderate medium subangular blocky structure; very hard, friable, sticky, plastic; few very fine roots; few very fine interstitial and few very fine tubular pores; many moderately thick clay films on peds, few moderately thick clay films in pores; slightly acid (pH 6.5); gradual irregular boundary. (3 to 5 inches thick)

BCqm--30 to 35 inches; reddish brown (5YR 5/4) very gravelly clay loam, reddish brown (5YR 4/4) moist; weak medium angular blocky structure; hard, very firm, sticky, plastic; few very fine interstitial pores; reddish yellow (7.5YR 6/6) bands of silica cementation 1 cm thick; common moderately thick clay films on peds; 50 percent by volume pebbles and cobbles; pebbles and cobbles have thin coating of silica on faces; neutral (pH 6.8); abrupt wavy boundary. (3 to 5 inches thick)

Bqm1--35 to 43 inches; pink (7.5YR 7/4) indurated platy duripan with common fine distinct black (N 2/ ) manganese mottles; very hard; extremely firm; very thin (less than 1 mm continuous opal cappings; pebbles and cobbles completely covered with silica coating; 10 percent pebbles and 80 percent cobbles by volume; clear wavy boundary. (4 to 12 inches thick)

Bqm2--43 to 47 inches; yellow (10YR 7/6) massive duripan of silica filling interstices and bridging mineral grains; very hard, extremely firm; 80 to 90 percent pebbles and cobbles by volume; coarse fragments have silica coatings on faces.

TYPE LOCATION: Modoc County, California- 1,050 feet south and 1,600 feet west of the east 1/4 corner of section 18, T.43N., R.14E.

RANGE IN CHARACTERISTICS: Depth to duripan is 24 to 40 inches. Depth to stratified cemented gravelly and cobbly alluvium is 28 to 50 inches. The mean annual soil temperature is about 47 degrees to 53 degrees F. and the soil temperature usually is warmer than 41 degrees F.
f.om February 20 to January 1. The soil temperature at depth of 20 inches is warmer than 47 degrees F. from about April 15 to December 1. The soil between depths of 4 to 12 inches is usually dry all of the time from June until October or early November and is moist in some or all parts when the soil is warmer than 47 degrees F. only from April 20 to July, and from October 20 to December 1. It is usually dry and is not moist more than 90 consecutive days when the soil temperature is warmer than 47 degrees F. The soil is slightly acid or neutral throughout the profile. Pebbles, cobblestone, or stones are present on the lower edges of the mounds where this soil is found, forming a "stone ring." Sand/clay ratio of the upper 15 inches is 1 to 4 and the organic matter averages more than 0.5 percent in the upper 15 inches.

The A horizon is pale brown and brown to pinkish gray (10YR 6/3, 6/2, 5/3, 5/2; 7.5YR 6/2, 5/2) dry and dark yellowish brown to very dark grayish brown (10YR 4/4, 4/3, 4/2, 3/4, 3/3, 3/2; 7.5YR 4/4, 4/2, 3/4, 3/2) moist. The upper 10 inches when mixed have dry value of 6. The A horizon has weak subangular blocky or platy structure or is massive. A3 horizon is absent in some pedons.

The Bt horizon is brown, reddish brown, reddish gray, or dark reddish gray dry and brown, dark brown, reddish brown, dark reddish brown, or dark reddish gray moist in 7.5YR or 5YR hue. The upper part tends to have 7.5YR hue and the lower part tends to be 5YR hue. The Bt horizon is gravelly and cobbly light clay loam, clay loam and sandy clay loam averaging 30 to 35 percent clay in the textural control section. Pebbles and cobbles average less than 35 percent although some subhorizons are higher. A thin,commonly discontinuous, horizon of very gravelly clay often occurs just above the duripan. The Bt horizon has moderate or strong angular or subangular blocky structure.

The Csim horizon has about 80 to 90 percent by volume of cobbles and pebbles with opal coatings on the underside. Manganese stains are common in the upper part. This horizon is massive or platy with thin continuous opal laminar layers in the upper part or is massive and indurated. The lower part is massive and very firm or extremely firm when moist.

COMPETING SERIES: These are the Deerlodge, Ditchcamp, Louie, Madras, Ochoco, Packwood, Puls, Selah, and Thoms series. Deerlodge soils have mildly and moderately alkaline B2t horizons and are calcareous in the lower horizons. Ditchcamp soils have hard bedrock below the duripan at depths of 25 to 40 inches. Louie soils have a calcareous Bt horizon, lime-cemented Cm horizons, and a xeric moisture regime. Madras soils have a paralithic contact of tuffaceous sandstone at depths of 25 to 40 inches and have 10 to 30 percent pumice fragments. Ochoco and Selah soils are mildly to moderately alkaline and calcareous in their lower horizons. Packwood, Puls and Thoms soils have duripans at depths of less than 20 inches.

GEOGRAPHIC SETTING: Exel soils are nearly level to moderately sloping and occur on nearly level to gently rolling hummocky lake terraces at elevations of 4,700 to 5,200 feet. Exel soils typically occupy the mounds and Thoms the intermound areas. They formed in lake terraces alluvium derived from basic igneous and pyroclastic rocks. The climate is semiarid mesothermal with warm dry summers and cold moist winters. Mean annual precipitation is 12 to 16 inches. Snowfall is 24 to 48 inches. Average January temperature is 28 degrees F.; average July temperature is 67 degrees F.; mean annual temperature is 46 degrees to 49 degrees F. The freeze-free season is 80 to 110 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Thoms soils and the Bieber, Barnard, Delma, Lovejoy and Modoc soils. Bieber soils have clayey B2t horizons and are less than 20 inches deep to a duripan. Barnard soils have clayey B2t horizon and have mollic epipedons. Delma soils have mollic epipedons and lack duripans. Lovejoy soils have abrupt A-B textural boundaries. Modoc soils have mollic epipedons.

DRAINAGE AND PERMEABILITY: Well-drained; slow or medium runoff; slow permeability.

USE AND VEGETATION: Used for grazing. The vegetation is sagebrush, sandberg bluegrass, Idaho fescue, bluebunch wheatgrass and cheatgrass.

DISTRIBUTION AND EXTENT: Valleys of the Modoc Plateaus in northeastern California. The soils are inextensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Modoc County (Alturas Area), California, 1974.

REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.

Series reclassified on September, 1994. Competing series not reviewed at that time.

OSED scanned by SSQA. Last revised by state on 5/74.

ADDITIONAL DATA: Riverside Laboratory sample 572 Calif 25-16. Not published to date.

National Cooperative Soil Survey
U.S.A.