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 (N 2 O) emissions. These soil N 2 O 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 N 2 O 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 N 2 O‐N ha −1 ) and PCU (5.48 kg N 2 O‐N ha −1 ). Soil N 2 O losses represented between 2.8 and 3.0% of annual fertilizer N applied, respectively. Strip‐till/deep banded N placement emitted 28% less N 2 O (0.2 kg N 2 O‐N) per Mg grain produced ( P = 0.0284) compared to that of no‐till/surface broadcasted N. Impacts of alternative management practices on soil N 2 O 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.