LOCATION RYDE               CA 

RYDE SERIES

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Cumulic Endoaquolls

TYPICAL PEDON: Ryde clay loam-on a 1 percent slope that is cultivated at 5 feet below sea level (Colors are for dry soil unless otherwise stated. When described on May 12, l977, the soil was moist throughout).

Ap--0 to 8 inches; grayish brown (10YR 5/2) clay loam, very dark grayish brown (10YR 3/2) moist; strong coarse granular structure; hard, friable, sticky and plastic; strongly acid (pH 5.5); clear smooth boundary. (8 to 12 inches thick)

A--8 to 24 inches; dark gray (10YR 4/1) clay loam, very dark gray (10YR 3/1) moist; few fine prominent reddish yellow (7.5YR 6/6, 6/8), brown (7.5YR 4/4) and strong brown (7.5YR 4/6) mottles moist; moderate coarse subangular blocky structure; extremely hard, firm, sticky and plastic; many fine roots; common fine tubular pores; strongly acid (pH 5.5); abrupt wavy boundary. (16 to 20 inches thick)

2Ab--24 to 32 inches; very dark gray (10YR 3/1) mucky clay loam, black (10YR 2/1) moist; common fine distinct dark brown (7.5YR 3/4) and strong brown (7.5YR 4/6) mottles moist; massive; slightly hard, firm, sticky and nonplastic; many fine roots; common very fine tubular pores; very strongly acid (pH 5.0); clear wavy boundary. (5 to 8 inches thick)

2Cg--32 to 63 inches; very dark gray (N 3/0) and dark grayish brown (2.5Y 4/2) stratified silty clay loam and sapric material, black (N 2/0) and very dark grayish brown (2.5Y 3/2) moist; few fine prominent dark brown (7.5YR 3/4), brown (7.5YR 4/4) and strong brown (7.5YR 4/6) mottles moist; massive; hard, firm, sticky and plastic; very strongly acid (pH 4.5).

TYPE LOCATION: San Joaquin County, California; about 4300 feet north and 5500 feet east of Tracy Road bridge on Middle River, Drexler Tract; 37 degrees 53' 41" north Lat., 121 degrees 26' 21" west Long (in an unsectionized area) Holt quadrangle.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 60 to 65 degrees F. The soil between the depths of 8 to 17 inches is not dry at any time unless the soil has been artificially drained. The profiles have some stratification throughout with variation in the amount of organic matter in the various layers or horizons. Distinct or prominent mottles are present from a depth of 10 to 20 inches down to a depth of 40 inches. The weighted average of the organic matter content ranges from 10 to 30 percent within the 10 to 40 inch control section. Layers with 27 to 35 percent clay and less than 10 percent organic matter are present in the 10 to 40 inch control section.

The A horizon is 10YR 5/1, 5/2, or 4/1; 5Y 4/1 or 5/2. Moist colors are 10YR 3/1 or 3/2; 5Y 2/1 or 3/2. It is clay loam, silty clay loam mucky clay loam or mucky silty clay loam. Reaction is strongly acid to neutral.

The 2Ab horizon, where present, is 10YR 3/1; 2.5Y 4/2; N 3/0. Moist colors are 10YR 2/1; N 2/0; 2.5Y 3/2. It is a mucky clay loam, mucky silty clay loam, mucky loam, or sapric material. Reaction is very strongly acid to moderately acid. The 2Ab horizon is lacking in some pedons.

The 2Cg horizon has dry colors of 10YR 7/1, 5/1, 4/1, 3/1; 2.5Y 7/2, 5/2, 4/2, 3/2; N 4/0, N 3/0, N 2/0. Moist variegated colors are 10YR 4/2, 4/1, 3/2, 3/1, 2/1; 2.5Y 4/2, 3/2, 2/2; N 2/0; 5Y 4/2, 4/1, 3/1, 2/1. The texture is stratified silty clay loam, loam or clay loam. Most pedons have lenses of mucky clay loam, mucky silty clay loam, sapric material or ash (burned peat) layers that range from 1/2 inch to 5 inches thick. Reaction is very strongly acid to moderately acid. Some pedons have textures of stratified fine sandy loam, sandy loam, loamy fine sand, loamy sand, sand, or sapric material below 40 inches. Reaction of mineral horizons with low organic matter content is slightly acid to mildly alkaline.

COMPETING SERIES: These are the Kanebreak, Scribner and Sikeston series. Kanebreak soils have mean annual soil temperature of more than 63 degrees. Scribner soils are on slightly higher positions and have a weighted average of organic matter content of 1 to 10 percent in the 10 to 40 inch zone. Sikeston soils have soil temperatures below 47 degrees part of the year.

GEOGRAPHIC SETTING: The Ryde soils are on nearly level river deltas and flood plains. These soils formed in alluvium from mixed sources that contain hydrophytic plant remains. Elevations are 15 feet below sea level to 5 feet above sea level. Levees and pumps are required to control both surface and subsurface water. The climate is subhumid, mesothermal with hot dry summers and cool moist winters. Mean annual precipitation is 14 to 20 inches. Mean annual January temperature is about 47 degrees F.; the mean July temperature is 76 degrees F; and the mean annual temperature is about 60 to 61 degrees F. The frost-free season is 260 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Scribner soils, and the Kingile, Rindge, Shima, Valdez and Venice soils. Kingile, Rindge, Shima and Venice are on lower positions and are all organic soils. Valdez soils are on slightly higher positions, are fine-silty and have an ochric epipedon.

DRAINAGE AND PERMEABILITY: Very poorly drained; very slow runoff; moderately slow permeability. Some pedons with organic or sandy substratums have rapid permeability below 40 inches. The drainage of these soils has been altered by the use of levees and pumps. Water tables occur between 36 and 48 inches throughout the year. Flooding is rare due to protection by levees.

USE AND VEGETATION: Used mainly for irrigated cropland to produce crops such as wheat, alfalfa, irrigated pasture, sugar beets, tomatoes, field corn and safflower. Uncultivated areas have annual grasses and forbs, sedges and other hydrophytic plants.

DISTRIBUTION AND EXTENT: In the Sacramento-San Joaquin River Delta area of California. The soil is extensive in MLRA-16,17.

MLRA OFFICE RESPONSIBLE: Davis, California

SERIES ESTABLISHED: San Joaquin County, (Lodi Area) California, l932.

REMARKS: The type location has been moved from Solano County to San Joaquin County. This revision includes the characteristics of the Retryde series which is dropped.

Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - the zone from the surface to a depth of 24 inches (Ap,A).

Cumulic subgroup - mollic epipedon is 24 to 32 inches thick and has an irregular decrease of organic matter with increasing depth.

The base satruation of pedons with very strongly acid reactions needs to be checked. The Mucky loam and Mucky silt loam surface texture need to be checked to see if they are in the Histic subgroup.

Series reclassified 5/95. Competing series not updated at that time.