Abstract:

Upland-paddy rotations play a vital role in the middle Yangtze River region of China. It is crucial to rationally evaluate the environmental and economic benefits of different crop rotation patterns for sustainable crop production. This study investigated three upland-paddy rotations: maize-rice (MR), rapeseed-rice (RR), and wheat-rice (WR), to assess crop yields, energy efficiency, and carbon efficiency under two treatments: straw return (S+) and straw clearance (S-). The results revealed that the MR rotation had a significant increase in yield, with 22.25% and 14.81% higher yields compared to RR and WR, respectively. Incorporating straw return led to a significant improvement in crop yield for MR, RR, and WR, with increases of 7.12%, 6.54%, and 6.43%, respectively. Furthermore, the MR pattern exhibited significantly higher radiation energy utilization efficiency (RUE) and output / input ratio (O/I) compared to RR and WR, with significantly lower energy consumption intensity (EI). Straw return improved RUE for MR and WR, increased EI for RR and WR, and decreased O/I across all patterns. Additionally, carbon production efficiency and carbon ecological efficiency were significantly higher for MR compared to RR and WR. Straw return significantly improved efficiencies in all patterns. Moreover, the carbon footprint (CF) of MR was significantly lower than that of RR and WR, and straw return also reduced CF significantly in all patterns. Overall, the study results demonstrate that the MR rotation has higher crop yield, energy efficiency, carbon efficiency, and lower CF. Additionally, straw return can increase crop yield, improve energy efficiency and carbon efficiency, and reduce CF in all patterns. In conclusion, the maize-rice rotation with straw return can be considered a sustainable and beneficial technique for rice production in the middle Yangtze River region. 

Key words: upland-paddy rotation, straw return, energy efficiency, carbon efficiency, carbon footprint