Developing best management practices for late nitrogen applications in corn

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Stakeholders along the entire agri-food value chain, including consumers, have repeatedly stated their desire for food production practices that minimize environmental impacts without sacrificing competitiveness (price or quality). Developing more rational nitrogen (N) fertilizer management strategies for corn production would allow Canadian farmers to meet both goals simultaneously. Fertilizer N losses have a profound impact on global N biogeochemical cycling and regional nutrient pollution, but they also represent a significant economic inefficiency for the farmer. We are proposing to refine an N fertilizer strategy based on 'late' N fertilizer applications, applying N fertilizer much later in the season than traditionally done. Most farmers apply N fertilizer around planting, but late N strategies apply a large proportion of this N much later in the season, about 2.5 months after planting. This strategy has the benefit of synchornizing the application of fertilizer N to when corn N uptake rates are high, which reduces the risk of high N losses. Moreover, because fertilizer N is applied mid-season, late N strategies also allow farmers to refine the N rate they apply. Waiting 2.5 months after planting allows farmers to assess weather, soil and other variables to help them better determine the N rate they should apply. A farmer applying N around planting does not have this luxury. Proof-of-concept studies validating late N management have been carried out in Canada and elsewhere as farmers are increasingly interested in the strategy. There is a need to develop best management practices that maximize the benefits of late N strategies for farmers and reduce the deleterious impacts of N fertilizer use. The partnership will establish best management practices for late N applications, quantifying grain yield, economic returns, N volatilization losses and other N-related crop and soil variables.