Ammonia and nitrous oxide gas loss with subsurface drainage and polymer-coated urea fertilizer in a poorly drained soil

Abstract

Gaseous nitrogen (N) loss from denitrification and ammonia (NH₃) volatilization from poorly drained soils in corn (<i>Zea mays</i> L.) production can be significant, diminish production, and lead farmers to apply a high rate of N. Nitrous oxide (N₂O), a greenhouse gas that is emitted during denitrification, has a high global warming potential that contributes to climate change. Reducing gaseous N loss from poorly drained soils through drainage and N management in corn production is essential to minimizing the environmental impact and maintaining high yields. The objective of the study was to determine how subsurface tile drainage and applications of polymer-coated urea (PCU) affect soil N₂O emissions and N fertilizer-induced NH₃ volatilization loss from a claypan soil. Drainage water management treatments consisted of conventional subsurface tile drainage, managed subsurface tile drainage, and no-drainage in combination with N fertilizer source (noncoated urea [NCU] and PCU). Subsurface drainage treatments did not significantly (<i>p</i> ≤ 0.05) affect cumulative soil N₂O emissions and NH₃ volatilization loss compared to no-drainage. Averaged over 2010 to 2013, cumulative soil N₂O emissions from PCU was 2% of applied N, and NCU was 4% of applied N. Yield-scaled soil N₂O emissions were reduced 53% with PCU compared to NCU. The percentage fertilizer loss from NH₃ volatilization was significantly (<i>p</i> ≤ 0.05) reduced from 2.8% with NCU to 0.8% with PCU. These results suggest that use of PCU may assist in reducing cumulative losses of N₂O and NH₃ from poorly drained claypan soils, but drainage systems operating under this study9s environmental conditions did not affect gaseous N losses.