Energy, environmental, and economic benefits of integrated paddy field farming

Rice yields have stabilized in the Chengdu Plain, and the implementation of integrated paddy field farming has shown potential for enhancing resource utilization. However, further investigation is required to clarify its impact on production sustainability. Accordingly, this study compared grain yields, energy use, greenhouse gas emissions, and economic benefits of single cropping rice (SCR), rice-duck symbiosis (RDS), and rice-fish symbiosis (RFS) over a three-year period (2018-2020). The grain yields were 16.24%-23.96% higher in SCR than in RDS and RFS, but nitrogen fertilizer use was reduced by 31.93%-32.15% in RDS and RFS, and the partial factor productivity of nitrogen was increased by 21.96-23.82%. RDS and RFS required 1.87-2.00 times more energy than SCR and were only 55.36%-57.80% as efficient as SCR. They also had higher CO2 (36.10%-42.20%) and CH4 (8.01%-28.88%) emissions but lower N2O (0.02%-21.18%) emissions than SCR. Economically, RDS and RFS produced 1.30-1.48 times higher net benefits with 1.44-1.47 times higher costs than SCR. The benefit-cost ratio of RFS was comparable to SCR and 11.38%-11.87% higher than RDS. In summary, RDS and RFS consume more energy (feed accounts for more than half) but provide higher yields and better-quality proteins, which are crucial to improving farmer motivation and ensuring protein availability.