LOCATION WOO CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Calcic Haploxerolls
TYPICAL PEDON: Woo clay loam - on a slope of 1 percent near the edge of cultivated field at an elevation of 200 feet. (Colors are for dry soil unless otherwise stated. When described on May 11, 1979, the soil was moist below 5 inches).
Ap1--0 to 5 inches; brown (10YR 5/3) clay loam, dark brown (10YR 3/3) moist; weak medium subangular blocky and strong coarse platy structure; hard, friable, sticky and plastic; few very fine roots; no pores; organic matter is 1.1 percent; slightly effervescent with disseminated lime; moderately alkaline (pH 8.0); abrupt smooth boundary.
Ap2--5 to 10 inches; brown (10YR 5/3) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few very fine roots; few very fine tubular pores; organic matter is 1.2 percent; slightly effervescent with disseminated lime; moderately alkaline (pH 8.0); clear smooth boundary.
A--10 to 15 inches; brown (10YR 5/3) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few very fine roots; few very fine tubular pores; organic matter is 1.1 percent; slightly effervescent with disseminated lime; moderately alkaline (ph 8.0); clear smooth boundary. (combined thickness of the A horizon is 10 to 19 inches)
AC--15 to 22 inches; yellowish brown (10YR 5/4) clay loam (brown (10YR 5/3) on ped faces), dark brown (10YR 3/3) (very dark grayish brown (10YR 3/2) on ped faces) moist; strong medium prismatic and subangular blocky structure; hard, friable, sticky and plastic; few very fine roots, few very fine and fine tubular pores; many moderately thick pressure faces; slightly effervescent with disseminated lime and segregated as few fine seams; organic matter is 0.7 percent; moderately alkaline (pH 8.0); clear smooth boundary. (3 to 7 inches thick)
C1--22 to 30 inches; yellowish brown (10YR 5/4) clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, sticky and plastic; no roots; few very fine, fine, and medium tubular pores; slightly effervescent with disseminated lime; organic matter is 0.4 percent; moderately alkaline (pH 8.0); clear wavy boundary. (6 to 10 inches thick)
C2--30 to 37 inches; yellowish brown (10YR 5/4) clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, very friable, sticky and plastic; few very fine and medium tubular pores; strongly effervescent with disseminated lime; moderately alkaline (pH 8.0); clear wavy boundary. (6 to 24 inches thick)
C3--37 to 65 inches; yellowish brown (10YR 5/4) clay loam, dark yellowish brown (10YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, sticky and plastic; few very fine and medium tubular pores; violently effervescent with disseminated lime and segregated as common fine threads and few fine soft masses; moderately alkaline (ph 8.0).
TYPE LOCATION: Merced County, California; 5.7 miles south of the city of Los Banos; 840 feet west of Center Avenue; along north edge of farm road (Sturgeon Farms); at midpoint of north border of SE 1/4 of SE 1/4 of sec. 15, 1,300 feet north and 840 feet west of the SE corner of sec. 15, T. 11 S., R. 10 E.
RANGE IN CHARACTERISTICS: The soil between the depths of 5 to 16 inches is moist throughout from about December 15 to sometime in May and dry throughout from June to November. The soil temperature is warmer than 47 degrees F from January 30 to December 1. The mean annual soil temperature is 59 degrees to 64 degrees F. The particle-size control section of 10 to 40 inches averages 18 to 35 percent clay dry. Depth of lime ranges from 0 to 19 inches.
The A horizon dry color is 10YR 4/2, 4/3, 5/2, 5/4; or 2.5Y 5/2. Moist colors are 10YR 3/2, 3/3; or 2.5Y 3/2. It is loam, clay loam, or sandy clay loam and ranges from 18 to 40 percent clay content. Some pedons have a clay overburden with 40 to 45 percent clay content. Thickness ranges from 11 to 19 inches. Disseminated lime is none or slightly effervescent. Some pedons have up to 10 percent gravel. Organic matter ranges from 1 to 2 percent. It is neutral to moderately alkaline.
The C horizon dry color is 10YR 5/4, 6/3, 6/4, 6/6, 6/8, 7/3, 7/4, 7/6, 8/6; 2.5Y 5/4, 6/4, 6/6, 7/4, 7/6, 8/6; or 5Y 7/4. Moist colors are 10YR 3/2, 3/3, 3/4, 3/6, 4/3, 4/4, 4/6, 5/3, 5/4, 5/6, 5/8, 6/4, 6/6, 7/4; 2.5Y 4/4, 5/6, 6/4, 7/4; or 5Y 6/3. Some pedons have mottles of 10YR 4/3, 5/3, 6/8; 7.5YR 3/2, 3/4, 4/2, 4/6, 5/6; 5Y 5/1, 5/3, 6/1, 6/3, 5GY 4/1, 5/1, 6/1; N 2/0 or N 3/0, moist. Typically it is clay loam, loam, sandy clay loam, sandy loam, silt loam or silty clay loam with 18 to 35 percent clay content. In some pedons the lower part of the C horizon is clay loam or clay with 35 to 45 percent clay content, or stratified very gravelly loamy sand to gravelly sandy loam with 5 to 15 percent clay content and 15 to 30 percent gravel. It is slightly or strongly effervescent with disseminated lime. It is mildly or moderately alkaline.
COMPETING SERIES: These are the Apollo, Fontana, Nacimiento, and Sorrento series in the same family. Apollo soils have Bt horizons resting on a paralithic contact at depths of 40 to 60 inches. Fontana and Nacimiento soils have paralithic contact between 20 and 40 inches. Sorrento soils are noneffervescent to a depth of 20 inches and have 12 to 20 inches of precipitation.
GEOGRAPHIC SETTING: Woo soils are on alluvial fans adjacent to the valley terraces. These soils are formed in mixed alluvium dominantly from sedimentary rock sources. They are on nearly level topography. Elevations are 70 to 340 feet. The climate is semiarid with hot dry summers and cool moist winters. The mean annual precipitation is about 9 to 12 inches. Mean January temperature is about 45 degrees F; mean July temperature is about 77 degrees F; mean annual temperature is about 62 degrees F. Frost-free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Paver, San Emigdio, Stanislaus, and Vernalis soils. Paver soils have an ochric epipedon and are noneffervescent in the A horizon. San Emigdio soils are coarse-loamy. Stanislaus soils are fine. Vernalis soils have an ochric epipedon.
DRAINAGE AND PERMEABILITY: Well drained, but some areas are now wet because of irrigation with a water table at a depth of 48 to 60 inches from April through October; slow to medium runoff; moderately slow permeability.
USE AND VEGETATION: These soils are leveled and used for irrigated truck crops, field crops, and orchards.
DISTRIBUTION AND EXTENT: These soils occur in alluvial fans of the Central San Joaquin Valley adjacent to the Coast Range foothills. They are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County, California 1984.
REMARKS: These soils were formerly included with and mapped as Mocho and Sorrento soils in the Los Banos Area Report, series 1939. pH determined by colorimetric method using Thymol Blue and Hellige-Troug Triplex indicators. Texture determined by modified Bouyoucos method. Presence of lime determined by field HC1 double syringe kit. Organic matter determined by Walkley-Black digestion method.
The activity class was added to the classification in March of 2003. Competing series were not checked at that time. - ET