Effects of Nitrogen Management Optimization Practices on Rice Productivity and Nitrogen Loss: A Meta-Analysis

Abstract

Optimizing nitrogen fertilizer management effectively reduces active nitrogen losses in farmland. By clarifying the impact of different nitrogen fertilizer optimization practices on crop productivity and nitrogen loss, rational nitrogen fertilizer management strategies can be adopted to achieve stable crop yields and reduction in nitrogen application rates. Our study collected 476 peer-reviewed papers and used meta-analysis to analyze the impact of different optimization management practices (combined application of organic-inorganic N fertilizers, deep N fertilizer application, and enhanced-efficiency nitrogen fertilizers) on yield, nitrogen use efficiency, and nitrogen loss (N2O emissions, NH3 volatilization, N runoff, and N leaching). Optimized nitrogen management significantly increased yield by 4.80% -10.06%, nitrogen use efficiency was increased by 17.27%-21.42%, N2O was reduced by 10.22%-36.89%, NH3 was reduced by 7.06%-40.39%, N runoff was reduced by 9.04%-19.55%, and N Leaching was reduced by 7.07%-9.97% compared to the standard farmer management practices. The combined application of organic and inorganic fertilizers increased yield by 10.06%, but the N2O and NH3 emissions increased significantly with the increase in nitrogen application rate. Compared with the standard farmers' management practices, slow-release fertilizer application not only increased the yield and nitrogen use efficiency by 4.08% and 17.67%, respectively, but also resulted in reduced emissions, thus being suitable for application in the middle and lower reaches of the Yangtze River. The optimal management of nitrogen fertilizer application can reduce the N2O and NH3 nitrogen emissions without reducing the yield. Furthermore, the implementation of slow-release fertilizers can effectively mitigate nitrogen losses while maintaining optimal crop yields, which is an effective strategy to ensure food security and improve the sustainable agricultural development.

Keywords: Rice, Nitrogen fertilizer management optimization, yield, Active nitrogen emissions, Meta-analysis