Balance rice high-yielding, high-quality and high-economic by changing the irrigation and fertilization management for sustainable production in China

Coordination of yield, quality and economic benefits increase remains an attractive problem in agricultural production. This study investigated how irrigation regimes could synergistically interact with different fertilization to increase irrigation water use efficiency (IWUE), yield, quality and output/input ratio in rice. A field experiment was conducted during 2020-2021 with three fertilization management (straw returning, organic fertilizer, conventional fertilizer) and two irrigation regimes (controlled irrigation (CI) and flood irrigation (FI)). This study reveals that CI reduced rice plant height (5.24% - 11.99%), tiller number (9.52% - 26.31%), SPAD (7.98% - 15.83%), yield (9.12% - 9.23%), and protein (4.85% - 5.02%) compared to FI. Conversely, CI improved chalky grain rate (5.83% - 8.52%), chalkiness (11.35% - 14.68%), IWUE (51.01% - 59.91%). CS (controlled irrigation + straw returning) and CM (controlled irrigation + organic fertilizer) significantly boosted rice quality and yield compared to CF (controlled irrigation + conventional fertilizer): setting rate increased by 20.23% (CS) and 18.20% (CM), yield rose by 19.43% (CS) and 19.83% (CM), and positive impacts were observed in polished rice rate, head milled rice rate, and protein content. However, both CS and CM led to reduced amylose content (0.35% and 1.06%) and taste value (0.82% and 3.25%). The study observed consistent interannual changes in straw returning, while variations were noted in organic fertilizer application. This difference was primarily attributed to the significant influence of temperature (with a 5.34 celcius difference during the two years at the milky ripening stage). The analysis of economic benefits showed that the output/input ratio of CS was the highest, ranging from 2.69% to 2.88%. By employing the TOPSIS method, an integrated multi-index decision analysis approach, CS was identified as the optimal mode for rice in southern China. The study provides an optimal irrigation and fertilization model for the synergistic realization of water saving, high yield, high quality, economic benefits, and further achieves the goal of sustainable agricultural development.