LOCATION DOSPALOS CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, calcareous, thermic Vertic Endoaquolls
TYPICAL PEDON: Dospalos clay loam - on a slope of 1 percent in a cultivated cotton field at 95 feet elevation. (Colors are for dry soil unless otherwise stated. When described on November 18, 1976, the soil was moist throughout).
Apk--0 to 9 inches; dark gray (10YR 4/1) clay loam, very dark gray (10YR 3/1) moist; common fine prominent light gray (10YR 7/1) masses of iron depletions, dry and moist; strong fine and medium granular structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine tubular and interstitial pores; strongly effervescent, carbonates disseminated and segregated as few fine irregular soft masses; moderately alkaline (pH 8.0); abrupt smooth boundary. (7 to 13 inches thick)
Ak--9 to 24 inches; dark gray (N 4/0) clay loam, black (N 2/0) moist; common fine prominent white (10YR 8/1) and light brownish gray (2.5Y 6/2) masses of iron depletion; common fine prominent white (10YR 8/1) and grayish brown (2.5Y 5/2) mottles moist; strong medium and coarse angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine and fine roots; few very fine tubular pores; many pressure faces on faces of peds; strongly effervescent, carbonates disseminated and segregated as many medium irregular soft masses; moderately alkaline (pH 8.0); clear wavy boundary. (14 to 18 inches thick)
ABk--24 to 27 inches; gray (5Y 5/1) and gray (5Y 6/1) clay, very dark gray (5Y 3/1) and dark gray (5Y 4/1) moist; common medium distinct white (5Y 8/1) masses of iron depletions, common medium prominent pale yellow (5Y 8/2) mottles moist; strong medium angular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; few very fine tubular pores; many pressure faces on faces of peds; violently effervescent, carbonates disseminated and segregated as many medium irregular soft masses; moderately alkaline (ph 8.0); clear wavy boundary. (3 to 13 inches thick)
Bwg--27 to 37 inches; pale olive (5Y 6/3) clay, olive (5Y 4/3) moist; common fine prominent light olive brown (2.5Y 5/6) masses of iron accumulations, common medium prominent light olive brown (2.5Y 5/6) masses of iron accumulations moist; moderate medium subangular blocky structure; very hard, very firm, very sticky and very plastic; few very fine roots; common very fine tubular pores; common pressure faces on faces of peds; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.0); diffuse smooth boundary. (8 to 12 inches thick)
C1--37 to 54 inches; light yellowish brown (2.5Y 6/4) clay loam, dark grayish brown (2.5Y 4/2) moist; common medium prominent brownish yellow (10YR 6/8) masses of iron accumulations; common medium prominent yellowish brown (10YR 5/8) masses of iron accumulations moist; weak medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common very fine and few fine tubular pores; common pressure faces on faces of peds; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.0); diffuse wavy boundary. (8 to 18 inches thick)
C2--54 to 62 inches; light yellowish brown (2.5Y 6/4) sandy clay loam, grayish brown (2.5Y 5/2) moist; common medium prominent brownish yellow (10YR 6/8) and very dark gray (10YR 3/1) masses of iron accumulations, common large prominent yellowish brown (10YR 5/8) masses of iron accumulations moist; massive; slightly hard, friable, slightly sticky and moderately plastic; common very fine and few fine tubular pores; few pressure faces; moderately alkaline (pH 8.0).
TYPE LOCATION: Merced County, California; approximately 5 miles east northeast of the city of Los Banos, 0.15 mile (800 feet) north of Baker and Delta Roads intersection, 200 feet east of Delta Road; 0.25 mile north of the southwest corner of sec. 3, or 200 feet east and 1,400 feet north of the southwest corner of section 3, T. 10 S., R. 11 E., MDB&M; Latitude 37 degrees, 06 minutes, 15 seconds north and Longitude 120 degrees, 45 minutes, 37 seconds west; USGS Los Banos Topographic Quadrangle, NAD 27.
RANGE IN CHARACTERISTICS: These soils are saturated with stagnant water for at least a few days. The thickness of the mollic epipedon ranges from 24 to 33 inches, primarily because of land leveling. The 10 to 40 inch particle-size control section averages 35 to 50 percent clay but can range from 35 to 60 percent clay. Organic matter content is 1 and 3 percent in the upper 24 inches and decreases regularly with depth. The soil has less than 15 percent calcium carbonate equivalent content throughout and typically decreases with depth. Surface cracks range from 0.75 to 1 inch and decrease to 0.5 to 0.75 inch at 20 inches of depth. There are no sphenoids or intersecting slickensides. Salinity is typically less than 2 decisiemens per meter but is 4 to 16 decisiemens per meter throughout in some pedons. It is slightly to strongly effervescent with disseminated carbonates from a depth of 10 inches to over 40 inches.
The A horizon has color of 10YR 2/1, 3/1, 4/1, 5/3; N 4/0; 2.5Y 4/2; 5Y 4/1, 5/1, 6/1 or 3/2. Moist color is 10YR 2/1, 3/1, 3/2, 4/1, 5/1; 5Y 3/1, 3/2, 4/1; 2.5Y 2/2; N 2/0 or N 3/0. Texture is clay loam or clay. Reaction is slightly alkaline or moderately alkaline. It is slightly effervescent or strongly effervescent with disseminated carbonates below a depth of 10 inches.
The Bwg horizon has color of 5Y 6/1, 6/2 or 6/3. Moist color is 10YR 4/3, 5/3; 5Y 4/1, 4/2, 4/3, 5/1, 5/2, 5/3 or 2.5Y 4/2. Texture is clay loam or clay. Clay content typically is 35 to 60 percent. Sodium adsorption ratio averages less than 3 but ranges up to 12. It is slightly effervescent or strongly effervescent with disseminated carbonates.
The C horizon has color of 10YR 5/2, 5/4, 6/2, 6/3; 2.5Y 5/4, 5/6, 6/4; 5Y 5/2, 5/3, 6/1, 6/2 or 6/3. Moist color is 10YR 4/2, 4/3, 5/3; 5Y 4/1, 4/2, 4/3,5/1, 5/2 or 5/3; 2.5Y 4/2 or 5/2. Texture is sandy clay loam, clay loam or clay.
COMPETING SERIES: This is the
Portageville (MO) series. Portageville soils (MLRA 131), on flood plains, have 45 to 50 inches mean annual precipitation and has a mollic epipedon that is commonly 10 to 20 inches thick, but is less than 24 inches.
GEOGRAPHIC SETTING: Dospalos soils are in valley basins. Slope is 0 to 2 percent. These soils formed in mixed alluvium mostly from granitic rocks. Most of these soils have been land leveled, but were hummocky in their natural landscape. Elevation is 60 to 120 feet. The climate is semiarid with hot dry summers and cool moist winters. The mean annual precipitation is 9 to 12 inches. The mean annual temperature is 60 to 64 degrees F. Frost-free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bolfar, Elnido, Escano, Kesterson, and Palazzo soils. Bolfar soils, in valley basins and on flood plains, have a fine-loamy particle-size control section. Elnido soils, on channels, flood plains, basin floors and valley basins, have a coarse-loamy particle-size control section. Escano and Kesterson soils, on valley basins, have a fine-loamy particle-size control section and a calcic horizon. Palazzo soils, on valley basin floors and flood plains, have a fine-loamy particle-size control section and organic matter that decreases irregularly with depth.
DRAINAGE AND PERMEABILITY: Poorly drained; negligible to medium runoff; slow permeability. These soils were previously ponded with stagnant water for extended periods during winter and spring months and are now ponded for periods of 2 to 7 days from December to February. The water table is now 3 to 5 feet December through March. They are now artificially drained or have had their water source intercepted. Most areas are protected from major flooding by large flood control levees and reservoirs.
USE AND VEGETATION: Most of these soils are cultivated and irrigated. They are principally used for field crop and vegetable production with small acreages of pastures, the remainder are used for annual livestock grazing.
DISTRIBUTION AND EXTENT: These soils occur near the San Joaquin River in the central part of the San Joaquin Valley of California. They are moderately extensive. MLRA 17.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County, California 1984.
REMARKS: These soils were formerly included with and surveyed as the Merced series in the Los Banos Area, series 1939 report. These soils are being differentiated by characteristics that show a reducing environment (Aquic Moisture Regime), a thick epipedon and wide cracking which are not characteristic of the Merced series. pH determined by colorimetric method using Thymol Blue and Hellige-Truog Triplex indicators. Texture determined by modified Bouyoucos method. Sodium adsorption ratio determined by versenate method.
Dospalos soil is mapped as a taxadjunct in the Fresno County, California, Western Part Soil Survey. It differs from Dospalos series by having intersecting slickensides in the upper part of the B horizon and by having mean annual precipitation of 8 to 9 inches. Dospalos taxadjunct has NSSl lab data available approximately 1.5 miles south of the Merced County line, for pedon sample number S87CA019-015 (1489-1497). Further investigation of the Dospalos series is warranted to determine if this series should be in the Vertisol soil order. Evidence for this change would include the COLE values of pedon S87CA-019-015 located close to Merced County, California, Western Part Soil Survey. Other evidence includes sidewalks that have been displaced by the cracking and heaving of soil mapped as Dospalos series in the town of Dos Palos. There are many areas with large cracks several inches apart.