Environmental impact assessment of rice-fish culture with different land management models

As the goals of carbon peak and carbon neutrality have been proposed, low-carbon and green development has become an inevitable choice for countries worldwide to solve environmental problems and achieve sustainable development. Because agricultural carbon emissions are a considerable part of global carbon emissions, the green transformation and development of agriculture has been regarded as an important basis for the establishment of a green and sustainable economy. Therefore, the study of agricultural carbon emissions is of great significance for China to explore agricultural green transformation and development, and the environmental impact assessment of carbon emissions can provide an important reference for this exploration. This study used the Qingtian Rice-Fish Culture System, the first Globally Important Agricultural Heritage System in China, as the research object, and selected Longxian Village, located in the core area of the heritage site, and Xinpeng Village and Xiaozhoushan Village, located in the radiation area, as the study area. A carbon footprint model based on life cycle assessment was constructed and used to evaluate the environmental impact of rice-fish culture using different land management models. The results showed that 1) although the carbon footprint of the rice-fish culture model that focused on developing terrace tourism was only 5779.1 kg(CO₂-eq)∙hm⁻², thereby making it the most advantageous for carbon emission reduction, its maximum carbon footprint per unit output value was 0.17 kg(CO₂-eq)∙¥⁻¹, which meant that the low economic benefit was not conducive to long-term sustainable development. 2) The economic benefit of the rice-fish culture model that focused on enlarging field fish raising was remarkable, and the carbon footprint per unit output value was only 0.05 kg(CO₂-eq)∙¥⁻¹; however, the high input of agricultural materials made its carbon footprint as high as 7928.6 kg(CO₂-eq)∙hm⁻² and caused high environmental risks. Therefore, a balance between economic output and environmental risk is urgently needed. 3) Supported by the local government, the rice-fish culture model that focused on maintaining traditional farming conserved the heritage of rice-fish culture and had a carbon footprint of 6266.7 kg(CO₂-eq)∙hm⁻² and a carbon footprint per unit output value of 0.12 kg(CO₂-eq)∙¥⁻¹; however, in the long-term, it is also necessary to improve the economic value of products and promote the integrated development of agriculture and tourism to achieve a win-win of economic and ecological benefits. The results reveal the significant differences in the economic and environmental benefits of the rice-fish culture with different land management models and provide a scientific basis for the formulation of green and sustainable development strategies for rice-fish culture systems under different land management models.