[Environmental impact differences in Qingtian rice-fish culture system at different management scales in the context of land transfer: An empirical study with the carbon footprint method.] / åœŸåœ°æµè½¬èƒŒæ™¯ä¸‹ä¸åŒç»è¥è§„æ¨¡é’ç”°ç¨»é±¼å ±ç”Ÿç³»ç»Ÿçš„çŽ¯å¢ƒå½±å“å·®å¼‚­­åŸºäºŽç¢³è¶³è¿¹çš„å®žè¯ç ”ç©¶.

Under rapid industrialization and urbanization, the conservation and management of agricultural heritage systems is facing many threats and challenges, such as the massive outflow of working labor, land abandonment, and the difficulty in maintaining traditional knowledge systems. Promoting land transfer and carrying out moderate-scale management play an active role in the conservation of agricultural heritage systems. While land transfer brings economic benefits to heritage sites, its environmental impacts to heritage sites are worthy of attention. However, empirical studies are scarce. This study took Qingtian rice-fish culture system in Zhejiang Province as an example, which was designated as Globally Important Agricultural Heritage Systems (GIAHS) in 2005. Small farmer management model and land scale management model were distinguished, while the life cycle method was used to calculate the carbon footprints of two models. The results showed that the carbon footprints of small farmer management model and land scale management model were 6510.80 and 5917.00 kg CO2-eq·hm-2, respectively, while the carbon footprints per unit output were 0.13 and 0.10 kg CO2-eq·yuan-1, respectively. Compared with small farmer management model, land scale management model had lower greenhouse gas emission and lower environmental impact of per unit output. As farmers expanded the scale of land management, local greenhouse gas emissions had been reduced by 4097.20 kg CO2-eq. Furthermore, the accumulation of CH4 in agricultural production accounted for the largest proportion of carbon footprint. The input of compound fertilizer among agricultural production materials was next to CH4 accumulation, becoming the second largest source of greenhouse gas emission. Corn and wheat being used as fish feed also had a significant impact on greenhouse gas emission in small farmer management model. Therefore, the promotion of moderate scale land management is conducive to the win-win of economic and environmental benefits of traditional agricultural systems and plays an important role in the conservation of agricultural heritage systems.