104—Willows silty clay, 0 to 1 percent slopes, frequently flooded

Map Unit Setting

General location: Lowest elevation areas of the Colusa Basin and Butte sink
MLRA: 17
Mapunit geomorphic setting: Basin floor
Elevation: 35 to 110 feet (12 to 35 meters)
Mean annual precipitation: 14 to 16 inches (355 to 405 millimeters)
Mean annual air temperature: 61 to 63 degrees F. (16 to 17 degrees C.)
Frost-free period: 225 to 250 days
Willows silty clay, frequently flooded—90 percent
Minor components: 10 percent

Major Component Description

Willows silty clay, frequently flooded

Component geomorphic setting: Basin floor
Parent material: Alluvium
Typical vegetation: Irrigated cropland

Willows soils flooded for rice production with the Coast Range in the background.
Figure 8 - Willows soils flooded for rice production with the Coast Range in the background.

Component Properties and Qualities

Slope: 0 to 1 percent
Runoff: Very low
Surface features: None noted.
Percent area covered by surface coarse fragments: None noted.
Depth to restrictive feature: None noted
Slowest permeability class: Very slow
Salinity: Saline within 40 inches
Sodicity: Sodic within 40 inches
Available water capacity: About 8.9 inches (High)

Component Hydrologic Properties

Present flooding: Frequent
Present ponding: None
Current water table: Present
Natural drainage class: Poorly drained
Altered hydrology: Flood control structures on the Sacramento River have changed flooding frequency and duration and lowered water tables. Rice drainage ditches have lowered water tables. Accumulation of salts at the surface may have been removed through reclamation efforts or ponding for rice production. Willows soil in this map unit is frequently flooded for long duration.

Interpretive Groups

Land capability irrigated: 4w-2
Land capability nonirrigated: 4w-2

Typical Profile

Ap1—0 to 5 inches; silty clay
Ap2—5 to 13 inches; silty clay
Bw—13 to 20 inches; silty clay
Bssy1—20 to 39 inches; silty clay
Bssy2—39 to 51 inches; silty clay
Bssy3—51 to 59 inches; silty clay
Bssy4—59 to 72 inches; clay
Bssy5—72 to 80 inches; silty clay
Bkssy—80 to 87 inches; clay

Estimated Minor Components

Capay clay loam, frequently flooded and similar soils

Composition: 0 to 5 percent
Slope: 0 to 1 percent
Component geomorphic setting: Basin floor

Unnamed

Composition: 0 to 2 percent
Slope: 0 to 1 percent
Component geomorphic setting: Channel

Willows silty clay, occasionally flooded and similar soils

Composition: 0 to 2 percent
Slope: 0 to 1 percent
Component geomorphic setting: Basin floor

Scribner silt loam, frequently flooded and similar soils

Composition: 0 to 1 percent
Slope: 0 to 1 percent
Component geomorphic setting: Flood plain

Additional Component Properties

See "Chemical Properties of Soils" table and the "Physical Properties of Soils" table for component horizon data.

For additional component horizon data, see the "Soil Properties" section of this publication.

A typical soil description with range in characteristics is included, in alphabetical order in the "Classification of the Soils" section.

Use and Management

Major uses: Irrigated crops
For information about management, see the "Use and Management" section of this publication.