Optimizing Cover Crop Integration: Early Establishment Methods and Technological Approaches for Enhanced Biomass and Nitrogen Management in the Mid-Atlantic
| dc.contributor.author | Lipford, Mary Michael | en |
| dc.contributor.committeechair | Reiter, Mark S. | en |
| dc.contributor.committeemember | Mott, Joshua Darell | en |
| dc.contributor.committeemember | Abaye, Azenegashe O. | en |
| dc.contributor.committeemember | Evans, Kristen Hughes | en |
| dc.contributor.department | Crop and Soil Environmental Sciences | en |
| dc.date.accessioned | 2025-01-10T09:00:42Z | en |
| dc.date.available | 2025-01-10T09:00:42Z | en |
| dc.date.issued | 2025-01-09 | en |
| dc.description.abstract | 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. | en |
| dc.description.abstractgeneral | This research examined ways to aid Mid-Atlantic farmers in establishing earlier cover crops (CCs) and improving CC nitrogen (N) uptake. The first part of the study compared broadcasting CCs at corn harvest with waiting four weeks to either broadcast or drill them after harvest. Four species of CCs were tested, including cereal rye, hairy vetch, rapeseed, and a mixture of these. Results over two years showed that broadcasting CCs at corn harvest resulted in significantly more biomass growth in the fall, with levels ranging from 721 to 846 kg per hectare (643 to 755 lb per acre), compared to just 134 to 200 kg per hectare (120 to 178 lb per acre) with later planting. Additionally, soil nitrate levels were lower when CCs were planted at harvest—5.2 mg/kg, compared to 11.4 to 11.8 mg/kg when planted later. Certain combinations, especially those including hairy vetch, led to higher N accumulation and improved corn yields. The second part of the study evaluated a new combine-mounted seeder that allows farmers to plant CCs during cash crop harvest, reducing the number of times they need to work the fields. Results after one year showed that the combine-seeded method produced similar or greater biomass and N accumulation than conventional post-harvest drilling. Following corn, fall biomass increased tenfold and spring biomass nearly doubled compared to delayed drilling. Even with drought conditions in soybeans, the combine-seeded method yielded results comparable to drilling CCs two weeks later. The second year of the study is still in progress. Overall, both studies suggest that starting cover crops earlier, whether by broadcasting or using the combine seeder, can significantly boost biomass growth while reducing nitrate leaching in farming systems throughout the Mid-Atlantic region. Future research is needed to test the effectiveness of the combine-mounted cover crop seeder in different soil types and climates. | en |
| dc.description.degree | Master of Science | en |
| dc.format.medium | ETD | en |
| dc.identifier.other | vt_gsexam:42252 | en |
| dc.identifier.uri | https://hdl.handle.net/10919/124081 | en |
| dc.language.iso | en | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject | cover crops | en |
| dc.subject | soil nitrogen capture | en |
| dc.subject | biomass production | en |
| dc.subject | nitrogen accumulation | en |
| dc.subject | broadcast seeding | en |
| dc.subject | combine-mounted cover crop seeder | en |
| dc.title | Optimizing Cover Crop Integration: Early Establishment Methods and Technological Approaches for Enhanced Biomass and Nitrogen Management in the Mid-Atlantic | en |
| dc.type | Thesis | en |
| thesis.degree.discipline | Crop and Soil Environmental Sciences | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | masters | en |
| thesis.degree.name | Master of Science | en |
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