Sulphur-coated urea reduces greenhouse gas intensity and enhances soil quality in rice cultivation

The Indo-Gangetic Plain (IGP) faces significant challenges related to greenhouse gas (GHG) emissions and declining soil health due to intensive rice-based cultivation systems. This study evaluated the efficacy of enhanced efficiency fertilizers (EEF), including slow-release fertilizer (Sulphur-coated urea, SCU), and nitrification inhibitors (Neem-coated urea, NCU; Karanj-coated urea, KCU) in reducing GHG intensity and improving soil biological activity in rice systems in the IGP. Field experiments conducted over two years assessed yield parameters, GHG emissions, and indicators of soil microbial biomass, nutrient content, and enzymatic activity. NCU reduced CH4 emissions by 11 % and N2O emissions by 16.5 % relative to prilled urea (PU), while SCU and KCU also demonstrated notable emission reductions. Sulphur coated urea demonstrated the lowest greenhouse gas intensity (GHGi) (0.128 kg CO2-eq kg−1 grain yield), followed by NCU and KCU. All EEFs significantly improved rice grain yield compared to PU, with SCU and KCU recording the highest mean yields (∼5600 and ∼5560 kg ha−1, respectively) versus 5010 kg ha−1 under PU. Additionally, EEFs improved microbial biomass carbon and nitrogen, dehydrogenase activity, and reduced nitrate reductase and urease activity compared to conventional prilled urea (PU), with KCU and SCU showing the greatest improvements and highest net returns. Among the EEFs, SCU consistently achieved the highest yield, lowest GHGi, and overall improvements in soil health, making it a promising alternative for sustainable rice production. Projections indicate that while application of NCU in the IGP region during rice cultivation could reduce the GHGi by 12.2 % while adopting SCU may achieve a 25.8 % reduction, supporting India's commitment to the Paris Climate Agreement and promoting sustainable agricultural practices in the IGP.