The economic benefits, energy use efficiency, and carbon footprint of fragrant super rice and nonfragrant super rice under different planting methods and nitrogen levels

BackgroundThe objective of this study was to investigate the input and output of energy, carbon input and sequestration, and economic benefits of fragrant and nonfragrant rice under different crop management practices, with the aim of providing theoretical guidance for sustainable rice production. Two high-yield and popular rice varieties, Yuxiangyouzhan and Jiyou615, were grown under three nitrogen fertilizer levels (0, 150, and 220 kg ha-1) and three planting methods (manual transplanting, mechanical transplanting, and mechanical direct seeding) during 2018 and 2019.ResultsThe results showed that the economic, energy, and carbon benefits of the different rice varieties varied in response to the different fertilizations and planting methods. The average energy outputs of Yuxiangyouzhan and Jiyou615 were 214 423.26 and 218 474.90 MJ ha-1, respectively. The mean harvest index and mean energy use efficiency of Jiyou615 were slightly greater, at 4.21% and 3.93%, respectively, than those of Yuxiangyouzhan, while the mean carbon input-sequestration ratio of Yuxiangyouzhan was slightly greater, at 1.79%, than that of Jiyou615. Yuxiangyouzhan had a significantly greater mean benefit-cost ratio (5.76%) than Jiyou615. In addition, Yuxiangyouzhan had a significantly greater mean nominal economic return on energy input (12.21%), nominal economic return on energy output (13.20%), nominal economic return on carbon input (12.65%), and nominal economic return on carbon sequestration (11.31%) than Jiyou615.ConclusionThe results suggest that suitable high-yield and high-quality varieties with better consumer demand and the synergistic effect of variety and crop management in sustainable rice production are highly meaningful. (c) 2025 Society of Chemical Industry.