Anticipated soil quality and other benefits have generated interest in adoption of no-till practices on organic farms. Vegetative mulch provided by killed cover crops is relied on heavily for weed suppression in no-till organic systems. This project included one study where 12 different cover crop treatments were screened for potential use in no-till organic systems at locations in IA, MN, ND, and WI, with up to 10 different treatments evaluated at any one location. Different methods of terminating cover crops were compared with a no-till method (rolling-crimping) common to all locations. A separate field study compared performance of up to five different market crops when seeded directly into rolled-crimped cover crop mulch at three locations. Fall-seeded small-grain crops produced over 14,000 kg/ha (12,500 lb/ac) in WI and hairy vetch over 8000 kg/ha (7140 lb/ac) in ND of rolled-crimped vegetative mulch and have the greatest near-term potential as cover crops in no-till organic farming systems. Grain production was successful when soybean was seeded directly into cover crop mulch, but problems were encountered when corn and other grain crops were grown. Refinement of the rolling-crimping method for killing cover crops, screening of additional cover crop species, and modification of current no-till organic farming strategies are needed so that crops in addition to soybean can be grown using no-till organic practices in the north central region.
The primary objective of this project was to develop management recommendations for killing cover crops mechanically without tillage, and using the vegetative mulch that was produced for weed suppression in no-till organic grain production systems in the north central region. Specific objectives were to: (1) identify cover crop species and species mixtures that produced large amounts of above-ground dry matter (DM); (2) determine if cover crops could be killed effectively by rolling-crimping under environmental conditions in the north central region; (3) grow field crops successfully following rolling-crimping of cover crops; and (4) stimulate adoption of organic no-till methods on at least one organic farm in IA, MN, ND, and WI.