Crops including grasses, legumes or forbs used for seasonal cover and other conservation purposes.
SARE Publications 2007, Managing Cover Crops Profitably, 3rd Edition. Beltsville, MD: Sustainable Agriculture Network, 244 pgs. $19 for book; PDF version available.
Cropwatch (2007 archives): Cover crops offer benefits after early crop harvest
Cover Crops in SE Nebraksa-Gage County Extension Potential cover crops in SE Nebraska. Informational slides in PDF format by Paul C. Hay, on crops which could be used before soybeans, milo.
Natural Resources Conservation Service References Conservation practice standard on cover crops.
No-Till On the Plains Association Link to no-till discussion board; list of articles