The Cooperative Extension is the a way for academia to interact directly with with normal people, especially farmers. Mandated by the fact that the University of California is a Land Grant University, the UC Davis Cooperative Extension works directly with agriculture and industry, offering educational programs in farm management, 4-H, nutrition and family and consumer sciences throughout California.
Most (if not all) of the faculty who participate in the extension are under the College of Ag. A few faculty are considered full-time for the Extension and don't teach any courses, but most are also professors who teach at least a few courses.
Funding for all of the research the University does for the little guys comes from the Extension Service of the USDA.