Balance rice yield and eating quality by changing the traditional nitrogen management for sustainable production in China

Abstract

Total yield of rice in China has been greatly improved in recent decades. However, this yield improvement is excessively dependent on the input of nitrogen (N) fertilizer. In recent years, since the demand for rice quantity has basically been met, consumers pay more attention to rice quality, especially the eating quality. Increasing N application improves the yield of rice, but it changes the protein and amylose content in rice, generally reducing the eating quality. It is necessary to establish a more reasonable N management to balance yield and eating quality for rice sustainable development in China. In this study, we assessed the effectiveness of various N managements on rice yield and eating quality by meta-analysis. Under traditional N management, increasing the amount of total N and late-stage N applications weaken the yield increase and decrease the eating quality with the significant increase in protein and amylose content in rice. By reducing total N and late-stage N application input, eating quality and N use efficiency could be significantly improved. Further, conditional inference tree analysis indicated that adjusting the amount of late-stage N application was a major measure to improve traditional N fertilization, since it could increase agronomic N use efficiency in rice production and balance yield maintenance and eating quality improvement. Our supplementary experiment results further confirmed that adjusting N management could improve the rice yield and eating quality with less N input. Thus, we propose the following adjusting N management strategies for rice sustainable production in China: (1) Decreasing the traditional high N rate is absolutely necessary, although it will slightly decrease rice yield, but significantly improve rice eating quality and N use efficiency; (2) Reducing the amount of late-stage N application appropriately could improve the rice eating quality; (3) Improving agronomic N use efficiency is the key to balance rice yield and eating quality. Our results provide an important reference for the future N management in rice production for the purpose of achieving high yield and better eating quality.