LOCATION KESTERSON CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Glossic Natraqualfs
TYPICAL PEDON: Kesterson sandy loam - on a slope of 2 percent under filaree, saltgrass, alkali sacaton, and other annual grasses and salt tolerant herbs at 80 feet elevation. (Colors are for dry soil unless otherwise stated. When described on November 16, 1976, the soil was moist throughout).
A--0 to 1.5 inches; dark grayish brown (10YR 4/2) sandy loam, very dark gray (10YR 3/1) moist; strong very fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine roots; few very fine tubular pores; slightly acid (pH 6.5); abrupt smooth boundary. (0.5 to 3 inches thick)
E--1.5 to 3 inches; gray (10YR 6/1) and dark gray (10YR 4/1) loam, gray (N 5/0) and very dark gray (N 3/0) moist; strong fine angular blocky structure; slightly hard, friable, nonsticky and slightly plastic; common very fine roots; few very fine tubular pores; many thin clay films on peds; neutral (pH 7.0); abrupt irregular boundary. (1 to 6 inches thick)
Btn1--3 to 6 inches; gray (5Y 5/1) clay loam, very dark gray (5Y 3/1) moist; many medium distinct very dark gray (5Y 3/1) mottles, many medium faint black (5Y 2/1) mottles moist; strong medium columnar structure; hard, very firm, slightly sticky and plastic; common very fine and few fine roots; few very fine tubular pores; many moderately thick clay films on peds and in pores; clean sand grains coat columns; slightly effervescent with disseminated lime; ESP is 32; strongly alkaline (pH 8.5); clear smooth boundary. (2 to 5 inches thick)
Btn2--6 to 12 inches; olive gray (5Y 5/2) and dark gray (5Y 4/1) clay loam, olive gray (5Y 4/2) and very dark gray (5Y 3/1) moist; few fine prominent brownish yellow (10YR 6/6) mottles, common fine prominent yellowish brown (10YR 5/8) mottles moist; strong fine and medium prismatic structure; very hard, very firm, slightly sticky and plastic; few very fine roots; few very fine tubular pores; many thick and moderately thick clay films on peds and in pores; clean sand grains coat prisms; slightly effervescent with disseminated lime; ESP is 36; strongly alkaline (pH 8.5); clear smooth boundary. (4 to 10 inches thick)
Btkn--12 to 26 inches; light brownish gray (2.5Y 6/2)and grayish brown (2.5Y 5/2) clay loam, grayish brown (2.5Y 5/2) and very dark gray (5Y 3/1) moist; few fine prominent brownish yellow (10YR 6/8) and white (10YR 8/1) mottles, few fine prominent yellowish brown (10YR 5/8) and light gray (10YR 7/2) mottles moist; strong fine and medium prismatic structure; hard, very firm, slightly sticky and plastic; few very fine roots; common very fine tubular pores; many moderately thick clay films on peds and line pores; slightly effervescent with disseminated lime; calcium carbonate equivalent is 8 percent; strongly alkaline (pH 8.5); clear irregular boundary. (7 to 14 inches thick)
Bkn1--26 to 46 inches; light brownish gray (2.5Y 6/2) and light gray (2.5Y 7/2) clay loam, dark grayish brown (2.5Y 4/2) and light brownish gray (2.5Y 6/2) moist; common fine prominent brownish yellow (10YR 6/8) mottles, common medium prominent yellowish brown (10YR 5/8) and light gray (10YR 7/2) mottles moist; moderate fine subangular blocky and angular blocky structure; hard, firm, slightly sticky and plastic; few very fine roots; common moderately thick clay films on peds and in pores; strongly effervescent with disseminated lime and segregated as common medium irregular soft masses; ESP is 35; calcium carbonate equivalent is 16 percent; strongly alkaline (pH 8.5); clear irregular boundary. (15 to 25 inches thick)
Bkn2--46 to 60 inches; pale olive (5Y 6/3) loam, grayish brown (2.5Y 5/2) and light brownish gray (2.5Y 6/2) moist; common medium prominent yellowish brown (10YR 5/8) and light gray (10YR 7/2) mottles moist; weak fine subangular blocky structure; hard, firm, slightly sticky and plastic; few very fine roots; few very fine tubular pores; many thin clay films on peds; violently effervescent with dissemianted lime and segrgated as common medium irregular soft masses; 2 percent durinodes; ESP is 32; calcium carbonate equivalent is 8 percent; strongly alkaline (pH 8.5).
TYPE LOCATION: Merced County, California; 13 miles north of the city of Los Banos. 1,850 east of Lander Avenue (N. Mercy Springs, J-14) 1.35 miles west of the San Joaquin River; 2,000 feet east and 1,700 feet west of the NW corner.
RANGE IN CHARACTERISTICS: These soils are saturated with stagnant water for at least a few days. The depth from the surface to the natric horizon (Btn1, Btn2, Btkn) ranges from 1.5 to 8 inches. The depth to the upper boundary of the calcic horizon ranges from 15 to 33 inches. Some pedons do not have an A horizon. The 3 to 23 inch control section averages from 28 to 32 percent clay but may range from 25 to 35 percent clay. Organic matter is less than 1 percent. Most profiles contain high percentages of mica.
The A horizon is 10YR 4/1, 4/2, 5/1, 5/2; N 5/0 or N 6/0. Moist colors are 10YR 3/1, 3/2, 4/1, 4/2, N 3/0, N 4/0 or N 5/0. It is slightly acid to moderately alkaline. It is sandy loam or loam with 10 to 20 percent clay content.
The E horizon is 10YR 4/1, 5/1, 6/1, 7/1, 7/2; 2.5Y 5/2 or 6/2. Moist colors are 10YR 3/1, 3/2, 4/1, 5/1; 2.5Y 3/1, 3/2, 4/2 N 3/0 or N 5/0. There may be faint mottling in some pedons. It is sandy loam or loam. 10 to 25 percent clay content. It is neutral to moderately alkaline and may be effervescent.
The Btn horizon is 10YR 5/2; 5Y 4/1, 5/1, 5/2, 6/3; 2.5Y 5/2, 6/2 or 7/2. Moist colors are 2.5Y 4/2, 5/2; 5Y 2/1, 3/1, 3/2, 4/2, 5/2 or 6/1. It is sandy clay loam or clay loam. Typically the calcium carbonate equivalent ranges from 2 to 8 percent. Some pedons have over 15 percent in the lower Bt horizon. EC ranges from 2 to 6 mmhos/cm. ESP ranges from 16 to 60.
The upper Bk1 horizon is 2.5Y 6/2, 7/2; or 5Y 8/1. Moist colors are 2.5Y 4/2, 6/2; 5Y 4/3, 5/2, 6/2 or 7/2. The value of the color is dependent on the lime content. It is loam, sandy clay loam or clay loam. The calcium carbonate equivalent ranges from 16 to 45 percent. ESP ranges from 15 to 50.
The lower Bk2 horizon is 10YR 8/2; 2.5Y 8/4; or 5Y 6/3. Moist colors are 2.5Y 4/2, 5/2, 6/2; 5Y 4/3, 5/2 or 7/2. It is stratified fine sandy loam, loam or clay loam. The calcium carbonate equivalent ranges from 2 to 12 percent. ESP ranges from 5 to 20. Durinodes range from 0 to 5 percent.
COMPETING SERIES: These are the Edminster series in the same family and the Rossi series in another family. Edminster soils lack a calcic horizon. Rossi soils have a fine control section and xeric moisture regime.
GEOGRAPHIC SETTING: Kesterson soils are in valley basins. Slopes are 0 to 2 percent. The soils formed in alluvium from mixed but dominantly granitic rocks. Most of these soils have a hummocky or channeled landscape. Elevations are 70 to 110 feet. The climate is semiarid with hot dry summers and cool moist winters. The mean annual precipitation is about 11 inches. The mean annual temperature is about 62 degrees F. The frost-free season is 210 to 280 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Edminster soils and the Alros, Bolfar, Dospalos, and Escano soils. Alros soils lack a natric horizon. Bolfar, Dospalos, and Escano soils have mollic epipedons and lack a natric horizon.
DRAINAGE AND PERMEABILITY: Poory drained; very slow runoff; very slow permeability. These soils were ponded and formed under very poor drainage with stagnant water but have their source of water intercepted by flood protection levees and reservoirs. They are not ponded, due to rainfall, for periods of 7 to 21 days from December to March. The water table is now 1 to 3 feet December through April. Some areas are inundated (ponded) and used for waterfowl habitat from September to April.
USE AND VEGETATION: These soils are used for range and irrigated pastures. The vegetation is filaree, saltgrass, softchess, alkali heath, and other perennial and annual grasses and forbs.
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 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 Rossi series in the Los Banos Area, series 1939 report. These soils are being differentiated by characteristics that show a reducing environment (Aquic Moisture Regime) and fine-loamy control section that is not characteristic of the Rossi series. pH determined by colorimetric using Thymol Blue and Hellige-Truog Triplex indicators. Texture determined by modified Bouyoucos method. Calcium carbonate equivalent determined by field kit. ESP determined by saturation extract.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET