Impact of Different Nitrogen Fertilizers and Residue Management Schemes On Ammonia Volatilization From Sugarcane Production in Louisiana.

Volatilization of ammonia (NH₃) from soil is a loss of nitrogen (N) nutrient for plant production as well as an issue of air quality. Ammonia is an active precursor of airborne particulate matters (ammonium sulfate, ammonium nitrate) and also acts as a secondary source of nitrous oxide (N₂O) emission. In this study, the impact of different N fertilizers and harvesting residue management schemes on NH₃ volatilization from sugarcane production were evaluated based on an active chamber method. The field experiment plots consisting of two sources of N fertilizer (urea and urea ammonium nitrate (UAN)) and two residue management practices namely residue retained (RR) and residue burned (RB) were established in a Commerce silt loam at St. Gabriel LSU AgCenter research station. The NH₃ volatilized following N fertilizer application was collected in an impinge containing diluted citric acid and was subsequently determined using an ion chromatography. The results showed that the average NH₃ flux was greater in urea plots than in UAN plots. The NH₃ emissions from the urea plots had greater correlation with water filled pore space (%) as compared to the UAN plots. On the hand, the residue retained soil had much higher NH₃ volatilization than the residue burned soil regardless of N fertilizer sources. Overall, the NH₃ loss was primarily found within the first 20 days following the N fertilization.