Challenges, strategies and research priorities in legume-based nitrogen management for organic small grain producers in the Northeastern US

Abstract

AbstractHigh yields and crop quality in organic small grain production can only be achieved through successful management of nitrogen. Experienced farmers and advisors in the Northeastern U.S. were asked to discuss the most pressing challenges in organic nitrogen management for organic small grain systems, with a particular focus on legume green manures (LGMs). Eighteen semi-structured interviews with 12 farmers and eight advisors were conducted between December 2017 and March 2018. The farmers employed a range of materials and practices for fulfilling the nitrogen fertility needs of their crops, including LGMs, animal manures and organic fertilizers. Farmers and advisors identified cost, overdependence on external nitrogen sources, nitrogen source access, diversifying rotations, weed management and predicting nitrogen mineralization of organic residues as major challenges in nitrogen management. Results indicated that cost-effectiveness in nitrogen management is essential, but that farmers consider additional factors, such as weed pressure and long-term soil health effects, when choosing nitrogen sources or practices. Legume-based nitrogen fertility is promising for small grain systems in this region, but structural challenges, such as the lack of animal agriculture proximal to grain operations, and limited cash crop markets, impede the development of diverse rotations that feature long-term legume sods. Recommendations include additional field-based research, including on-farm, participatory LGM studies as one avenue. Programming and educational outreach should focus on bolstering farmers' understanding of nitrogen mineralization of incorporated LGM residues, as well as their ability to anticipate and respond to sources of variability in LGM systems.