Dual inhibitors for mitigating greenhouse gas emissions and ammonia volatilization in rice for enhancing environmental sustainability

Abstract

The use of inhibitors retain nitrogen as ammonium in soil, giving plants ample time for its uptake. This can reduce nitrous oxide (N₂O) emissions, but extended retention may increase ammonia (NH₃) volatilization. This study assessed the efficacy of coated urea fertilizers in reducing greenhouse gas (GHG) emissions and NH₃ volatilization in rice fields. A field experiment with Pusa 44 rice in the kharif seasons of 2019 and 2020 compared unfertilized control (No N), prilled urea (PU), nitrification inhibitors (NIs): neem oil-coated urea (NCU), karanj oil-coated urea, and dual inhibitor (DI: Limus + NCU). The coated urea fertilizers were analysed with scanning electron microscopy, fourier transform infrared spectrometry, and energy-dispersive spectroscopy. Compared to PU, DI reduced N₂O emissions by 23.7%, methane by 11.9%, and NH₃ by 29.8%. DI also reduced NH₃ emissions by 36–39% compared to other NIs. Overall, DI can lower the global warming potential of rice cultivation in trans Indo-Gangetic plains region by 17.1% for both direct and indirect emissions, suggesting its significant potential to reduce India's contribution to total agricultural GHG emissions.