Ventura Soils Many different soil types are found throughout Ventura County. Although farm management practices influence most aspects of soil fertility, some soil properties, such as texture and mineralogy, originate from the area’s climate and geologic history.

Ventura OceanscapeUnderstanding the soil parameters that can and cannot be changed by management will help growers set yield goals and determine which crops are best suited for the land.
Ventura County sits on a network of tectonic faults, all related to the San Andreas, running north to south through California from Mexico to San Francisco. The resulting mountains and basins in Ventura County provide diverse parent materials that provide the basis for the area’s soils.

Ventura’s upland soils formed from shale, sandstone, or igneous rocks. Each type of parent material provides unique chemical and physical characteristics that can either enhance or inhibit the soil’s ability to support crops. The upland soils usually range from 1 to 4 feet deep and have clay loam textures with varying levels of silt.

Soils in Ventura County’s foot slopes and basins formed from alluvium, geologic parent material transported by water. Over thousands of years, the Santa Clara and Ventura Rivers and their tributaries have transported rock and sediment from the surrounding mountains into the area’s basins. Fast running water deposits coarse geologic material in the riverbeds, while progressively smaller mineral particles settle further from the main stream, carried by shallow, gently moving waters. Over time, the rivers change paths, altering the sediment deposition patter. The resulting floodplains and basins hold a range of different soil types based on the size and mineralogy of the alluvium.

Many ranches in Ventura County have high soil pH and calcareous soil properties. The calcareous soil is inherited from geologic parent material high in calcium carbonate (CaCO3). The carbonates raise soil pH and decrease nutrient availability.

San Andreas Fault Line

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San Andreas Map courtesy of geology.com.
Map Copyright: David Lynch.

Ventura Soil Map

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To learn about the soil types on your ranch, visit SoilWeb
or NRCS Web Soil Survey.