Cover crops: You were wondering about them? More and more, farmers are planting vetch, subterranean clover, crimson clover, bur medic, bell beans and plain old oats and cereal rye between orchard or vineyard rows to improve soil quality and water penetration, and to provide a biological source of nitrogen. The UC Davis-based UC Sustainable Agriculture Research and Education Program's new Progress Report 1993-95 is chock full of information on cover crops. Details are available on at least seven cover crop-related projects. "Cover crops are major ingredients in many biologically integrated farming systems," says SAREP analyst Robert Bugg. "They're often the first biological technique farmers use. Once growers see the benefit of cover crops, other related practices make more sense to adopt."