Optimizing Cover Crop Integration: Early Establishment Methods and Technological Approaches for Enhanced Biomass and Nitrogen Management in the Mid-Atlantic

The research explored strategies to improve cover crop (CC) establishment and nitrogen (N) uptake in response to the time constraints commonly faced by Mid-Atlantic farmers. The first study examined whether broadcasting CCs at corn harvest—using various incorporation techniques—can reduce nitrate leaching and enhance biomass production, compared to broadcasting or drilling CCs 4-weeks post-harvest. Four seeding methods were tested across a range of CC species, including cereal rye (Secale cereale L.), hairy vetch (Vicia villosa Roth), rapeseed (Brassica napus L.), and their mixture. Over two years, data revealed that CCs planted at corn harvest achieved significantly higher fall biomass (721 to 846 kg ha-1) than those seeded four weeks later (134 to 200 kg ha-1). Year 2 data showed a reduction in fall soil nitrate levels with at-harvest planting (5.2 mg kg-1), compared to post-harvest CC planting (11.4 to 11.8 mg kg-1). Additionally, certain at-harvest treatments, particularly those with hairy vetch and the mix, increased aboveground N accumulation (181 to 208 kg ha-1) and, in Year 1, improved corn yield (10,113 to 11,586 kg ha-1). The second study focused on a combine-mounted seeder's capacity to address similar N management goals in corn-soybean systems, allowing for seeding CCs directly at harvest and bypassing the need for additional field passes. Results from one year demonstrated that the combine-mounted seeder produced equal or greater biomass and N accumulation compared to delayed drilling. Following corn, the combine seeded treatments increased fall biomass tenfold (205 kg ha-1 vs. 1116 to 1314 kg ha-1) and nearly doubled spring biomass (2345 kg ha-1 vs. 5867 to 6323 kg ha-1). The effectiveness of at-harvest broadcasting was also evident even in late-season drought conditions following soybean, showing comparable results to drilling two weeks post-harvest (4528 kg ha-1 vs. 4434 kg ha-1). Both studies highlight that earlier CC establishment, whether by broadcast seeding with or without incorporation or utilizing combine-mounted seeders, offers a promising approach for enhancing biomass production and reducing fall nitrate leaching in Mid-Atlantic farming systems.