Optimizing nitrogen fertilizer application with green manure for enhancing nitrogen use efficiency and reducing nitrous oxide (N2O) emission from rice field

Nitrogenous fertilizers may be a key contributor to the emission of nitrous oxide (N 2 O) from crop field, a greenhouse gases (GHGs) that accelerate climate change, like global warming. However, under field condition impacts of substituting chemical nitrogen (N) fertilizer with green manure on N 2 O emissions from Indian paddy fields have not been adequately assessed. A two years field experiments were carried out in rice field with randomized block design (RBD) to evaluate of influences of the sole and integrated application of N fertilizers and green manure on crop yield, enhances nitrogen use efficiency (NUE), and effects on N 2 O emissions. Seven treatments are: F0 (Control, no fertilizer), F1 (N at recommended dose-RD @ 120 kg N ha − 1 ), F2 (30% reduce N at RD @ 84 kg N ha − 1 ), F3 (Diammonium phosphate @ 120 kg N ha − 1 ), F4 (Ammonium sulphate @ 120 kg N ha − 1 ), F5 ( Sesbania aculeate @ 5t ha − 1 + 60 kg N ha − 1 ) and F6 ( Crotalaria juncea @ 5t ha − 1 + 60 kg N ha − 1 ). The result shows that F5 reduced the cumulative N 2 O emission by 40.07% and enhanced the NUE and yield, by 24.59% and 22.22%, respectively, as compared with F1. Significant negative correlation between NUE parameters and N 2 O emissions were found throughout the rice growing season. The findings suggest that incorporating Sesbania aculeata with 50% reduction in fertilizer rate (60 kg N ha –1 ) compared to the recommended rate (@120 kg N ha –1 ) regarded as effective and efficient fertilizer management practice to mitigate climate change by minimizing GHGs emission like N 2 O emissions, while simultaneously ensure crop productivity.