LOCATION BISGANI CAEstablished Series
TAXONOMIC CLASS: Sandy, mixed, thermic Typic Endoaquolls
TYPICAL PEDON: Bisgani loamy sand - on a slope of 1 percent in an alfalfa field at 100 feet elevation. (Color is for dry soil unless otherwise stated. When described on April 8, 1976, the soil was moist throughout).
Ap--0 to 14 inches; grayish brown (10YR 5/2) loamy sand, very dark grayish brown (2.5Y 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; slightly alkaline (pH 7.5); clear smooth boundary.
Ag--14 to 20 inches; grayish brown (10YR 5/2) loamy sand, very dark grayish brown (2.5Y 3/2) moist; few fine distinct yellowish brown (10YR 5/8) moist redoximorphic features; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; many very fine interstitial pores; slightly alkaline (pH 7.6); abrupt smooth boundary. (The combined thickness of the A horizon is 10 to 22 inches)
Cg1--20 to 43 inches; light gray (2.5Y 7/2) coarse sand, light olive brown (2.5Y 5/4) moist; few fine distinct olive yellow (2.5Y 6/6) mottles, many fine distinct yellowish brown (10YR 5/8) moist redoximorphic features; single grain; loose, nonsticky and nonplastic; few fine and medium roots; many very fine interstitial pores; slightly alkaline (pH 7.6); clear smooth boundary. (15 to 30 inches thick)
Cg2--43 to 60 inches; light gray (N 7/0) coarse sand, light brownish gray (2.5Y 6/2) moist; common fine distinct olive yellow (2.5Y 6/6) moist redoximorphic features; single grain; loose, nonsticky and nonplastic; no roots; many very fine interstitial pores; slightly effervescent, carbonates disseminated; moderately alkaline (pH 8.0).
TYPE LOCATION: Merced County, California; about 10 miles north of the city of Dos Palos, 300 feet south of Pick Anderson Bypass, and 200 feet east of South Drain Number 3, 0.15 mile south of the northeast corner and 4,500 feet north and 50 feet west of the southeast corner, sec. 29, T. 9 S., R. 12 E., MDB&M; Latitude 37 degrees, 7 minutes, 29 seconds north and Longitude 120 degrees, 40 minutes, 16 seconds west; USGS Delta Ranch 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 is 10 to 22 inches because of land leveling. The clay content of the 10 to 40 inch particle-size control section is 1 to 10 percent but averages less than 5 percent. Organic matter is 1 to 3 percent in the upper 10 to 22 inches. Reaction is slightly acid or moderately alkaline.
The A horizon has color of 10YR 4/1, 4/2, 5/1, 5/2, 8/1; 2.5Y 4/2 or 5/2. Moist color is 10YR 2/1, 3/1, 3/2, 3/3; or 2.5Y 3/2. Texture is sandy loam, loamy sand or loamy coarse sand. The Ap horizon in some pedons has an overwash of clay loam. Some pedons are slightly effervescent.
The C horizon has color of 10YR 6/1, 6/2, 6/3, 7/1, 7/2, 7/3, 8/1. 2.5Y 6/2, 7/1, 7/2; or N 7/0. Moist color is 10YR 3/2, 4/2, 4/3, 5/3, 5/4; 2.5Y 4/2, 5/2, 5/4 or 6/2; 5Y 4/1, 4/2. Texture is sandy loam, loamy sand, loamy coarse sand, coarse sand or sand. Some pedons have 2 to 5 percent fine gravel.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Bisgani soils are on bars, flood plains, low alluvial fans, basin floors and valley basins. Soils formed in mixed alluvium derived dominantly from granitic rocks. Most of these soils have been leveled, but the natural landscape was bar and channel topography. Slope is 0 to 2 percent. Elevation is 20 to 155 feet. Climate is semiarid with hot dry summers and cool moist winters. Mean annual precipitation is 8 to 12 inches; mean annual temperature is 60 to 64 degrees F. The frost-free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Elnido, Bolfar, Dospalos, Escano and Palazzo soils. Elnido soils have a coarse-loamy particle-size control section and are on flood plain channels. Bolfar, Escano and Palazzo soils have a fine-loamy particle-size control section. Bolfar and Palazzo soils are on flood plains. Escano soils are on valley basins. Dospalos soils have a fine particle-size control section and are on flood plains.
DRAINAGE AND PERMEABILITY: Poorly drained; negligible runoff; rapid permeability. In some phases permeability is moderately rapid or moderately slow in the surface layers, but is always rapid below. In most areas of Bisgani soils the natural hydrology has been altered so that the soils are now considered to be drained. The presence of dams and reservoirs in the Sierra Nevada, pumping from the water table, use of tile and interceptor drains, filling of local sloughs and leveling of bar and channel topography help explain the altered hydrology. Prior to the altered hydrology, flooding was occasional or frequent of long duration from January through March, consequently, the native soils were very poorly drained having ponded channels with stagnant water for extended periods during the winter and spring months. Currently, depth to the water table is generally greater than 3.5 feet. In some areas the water table is at 0.5 to greater than 6.0 feet. Most areas are protected from major flooding by levees and reservoirs. Some areas are subject to rare, brief periods of flooding from December through June in years of abnormally high precipitation. In areas unprotected by levees, flooding is occasional or frequent.
USE AND VEGETATION: Most of these soils are cultivated and irrigated. They are principally used for field crops and vegetable production with small acreage of orchard and pasture. The remainder is annual range vegetation.
DISTRIBUTION AND EXTENT: These soils occur near the San Joaquin River in the central part of the San Joaquin Valley of California. They are not 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 Columbia series in the Los Banos Area, series 1939 report. These soils are being differentiated by having a sandy texture control section and a mollic epipedon. The pH was determined by colorimetric method using Thymol Blue and Hellige-Truog Triplex indicators. Texture was determined by modified Bouyoucos method.
Major Diagnostic Horizons and Features:
1. Mollic Epipedon --The zone from 0 to 14 inches (Ap) - Organic matter is assumed to be 1 to 3 percent. The thickness is 10 to 22 inches.
2. Aquic moisture regime - Formed under aquic conditions but now drained and protected. Still will have entire profile saturated for a short period of time by water table and stagnant surface water.
3. Sandy family -The clay content of the particle-size control section (10 to 40 inches) is 1 to 10 percent (Hydrometer method). Texture is sand or loamy sand.
4. Former competing series, Diehlstadt, is now classified Typic Epiaquolls.
5. In the Fresno County, California, Western Part, Soil Survey most A horizons were originally loamy sand. Leveling of the bars and plowing of the channels in the original landscape has altered surface texture to form sandy loam.