Plant crops, including cereal rye, oats, and winter wheat to temporarily protect the ground from wind and water erosion during times when cropland isn't adequately protected.  Cover crops add organic material to the soil, improve infiltration, aeration, and soil tilth. Also, cover crops improve water use efficiency and water quality; improve wildlife habitat; and break reproduction cycles of plant pests. 

NRCS Conservation Practice Standard for Cover and Green Manure Crop

NRCS Conservation Practice Standard for Conservation Crop Rotation