Impact of nitrification inhibitor with organic manure and urea on nitrogen dynamics and N2O emission in acid sulphate soil

Abstract

The accurate prediction of N transformation is an importantrequisite for optimizing N use efficiency in cropping systems. Anincubation study was conducted to verify the impacts of nitrificationinhibitor (NI) with organic manure (OM) and urea on N dynamicsand N2O emission in acid sulphate soil. The conducted experimentwas two-level factorial with 4 N sources (N1 = 100% of N from urea,N2 = 75% of N from urea + 25% N from rice straw, N3 = 75% of N fromurea + 25% of N from cow dung and N4 = 75% of N from urea + 25%of N from poultry dung) and two levels of NI (with and without DCD).The NI (Dicyandiamide — DCD) with OM + urea enhanced mineralN contents and it was the highest (255.07 μg∙g–1) for urea with DCDapplications. The highest net N-mineralization (213.07 μg∙g–1) wasrecorded for the application of urea with DCD and net nitrification(16.26 μg∙g–1) was recorded for the application of urea alone, but thehighest cumulative N2O emission (5.46 μg∙g–1) was in urea + poultrydung (PD). In addition, DCD most effectively inhibited net nitrification(28.78%) and N2O emission (32.40%) from cow dung (CD) and ureain the tested soils. The combination of DCD with CD and urea wasmore effective in reducing N2O emissions (43.69%). These resultssuggest that the DCD with CD and urea may be the most potentialcombination to reduce nitrification and N2O emission as well as Nloss from acid sulphate soil.