Co-incorporation of green manure and rice straw with reduced synthetic fertilizer benefits rice yield while decreasing gaseous N losses in double-cropped rice fields

Co-incorporation of green manure and rice straw in paddy fields is an effective practice to increase rice yield and N uptake, while the mechanisms of the application of green manure and rice straw on NH 3 and N 2 O emissions are still unclear. A 2-year field experiment was carried out to analyze the impacts of the co-incorporation practice on NH 3 and N 2 O emissions, soil parameters, and rice yield. This study assessed how the application amount of synthetic fertilizer combined with green manure and/or rice straw affects NH 3 and N 2 O emissions, soil organic carbon (SOC) and available nutrients (N, P, K), and rice yield. Our results showed that the co-incorporation of green manure and rice straw significantly reduced gaseous N emissions while maintaining rice yield. As compared to the conventional fertilization practice, the application of green manure and/or rice straw decreases the NH 3 and N 2 O emissions by 7.5%-30.1% and 9.2%-45.5%, respectively. Annual gaseous N losses ranged from 68 kg N ha −1 to 245 kg N ha −1 , with NH 3 emissions dominating gaseous N losses. Co-incorporation of green manure and rice straw decreased the gaseous N losses by 11.0%-33.1% as compared with conventional fertilization practice. Moreover, the partial least squares path modelling revealed that the NH 3 and N 2 O emissions were mainly driven by changes in N input. Our study shows that co-incorporation of green manure and rice straw could reduce gaseous N losses and maintain the rice yield.