Nitrous Oxide Emissions from Claypan Soils Due to Nitrogen Fertilizer Source and Tillage/Fertilizer Placement Practices

Abstract

Poorly drained soils can potentially have large amounts of applied fertilizer N lost through denitrification which can be a major contributor to soil nitrous oxide (N2O) emissions. These soil N2O emissions due to agricultural practices are significant because they contribute to global warming and ozone depletion. The objectives of this research were to quantify the effects of tillage/fertilizer placement (i.e., no‐till/surface broadcast and strip‐till/deep banded) and N fertilizer source [i.e., non‐coated urea (NCU), polymer‐coated urea (PCU), nontreated control] on soil N2O emissions from corn (Zea mays L.) production over the 2009 and 2010 growing seasons in a poorly drained claypan soil in Northeast Missouri. Averaged over 2009 and 2010, no significant differences were observed in cumulative soil N2O emissions, between treatment plots with NCU (5.21 kg N2O‐N ha−1) and PCU (5.48 kg N2O‐N ha−1). Soil N2O losses represented between 2.8 and 3.0% of annual fertilizer N applied, respectively. Strip‐till/deep banded N placement emitted 28% less N2O (0.2 kg N2O‐N) per Mg grain produced (P = 0.0284) compared to that of no‐till/surface broadcasted N. Impacts of alternative management practices on soil N2O losses may also need to consider changes in agricultural production to allow producers to decide which practices are best suited to balance their production and environmental goals.