Authors: Sarah Light – UC Cooperative Extension Agronomy Advisor, Sutter, Yuba, Colusa Counties; Margaret Lloyd – UC Cooperative Extension Small Farms Advisor, Yolo, Solano, Sacramento Counties; Helaine Berris – Graduate Student, UC Davis, Department of Land, Air, and Water Resources; Donald Stewart – Staff Research Associate, Department of Agricultural and Resource Economics, UC Davis; Brittney Goodrich – UC Cooperative Extension Specialist, Department of Agricultural and Resource Economics, UC Davis
This cost study models the planting and management of a winter cover crop in a summer crop rotation planted in the lower Sacramento Valley of California. The rotation may include processing tomatoes, corn, sunflower, safflower, sorghum, and/or dry beans, as well as other summer annual crops. This study models a field following harvest of processing tomatoes in the fall and a planned rotation into a spring planted field crop.
The most commonly grown cover crop species are selected from three plant families: Leguminosae (such as bell beans, peas, clover, and vetch), Brassicaceae (such as mustard, turnip, and radish), and Poaceae (such as barley, oats, wheat, rye, and triticale). A mix of vetch, peas, and rye were used for this cost study.
Cover crops are plant species selected and grown for their protective and beneficial contributions to soil quality and function. They are not intended or managed as a cash crop and provide an alternative to fallowing. No consideration of an economic return is included in this cost study. A wide diversity of cover crop species and mixes are available for a variety of soil and crop health benefits. This cost study models the planting and management of a cover crop during the winter fallow period in an annual rotation on a per acre basis.
Compared to a fallow field, cover crops improve soil health. In the short term, the potential benefits of a cover crop are to minimize top soil loss from erosion, suppress weed growth, improve water penetration and infiltration, slow surface water runoff, add diversity to crop rotations, increase soil nitrogen, and provide food for pollinators, beneficial insects and soil fauna. After several years of repeated cover cropping increased soil organic matter, increased water holding capacity, and improved soil structure can be expected.
In annual crop rotations in the lower Sacramento Valley, cover crops are commonly planted from October to December, grown during winter with soil moisture provided by rainfall and sometimes irrigation, and terminated and incorporated into the soil from late February through April.
For an explanation of calculations used in the study, refer to the section titled Assumptions. For more information contact the Department of Agricultural and Resource Economics, at 530-752-4651, destewart@ucdavis.edu. The local UC Cooperative Extension office contacts are Sarah Light, selight@ucanr.edu and Margaret Lloyd, mglloyd@ucanr.edu.