关键词: 碳足迹, 碳排放, 轮作, 烟草, 辣椒, 大豆, 红薯, 经济效益, 豫中地区

Abstract:

【Objective】This study aimed to clarify the economic benefits and carbon emission characteristics under different cropping patterns, so as to provide a scientific basis for the selection of regional dominant cropping rotation patterns.【Method】Based on the survey data of farmers in Xiangcheng County, Xuchang City, central Henan Province from 2018 to 2022, this study calculated the carbon emissions of four different rotation patterns: cereal-vegetable-tobacco (wheat-pepper-wheat-pepper-wheat-pepper-tobacco), wheat-maize-tobacco (wheat-maize-wheat-maize-wheat-maize-tobacco), cereal-soybean-tobacco (wheat-maize-wheat-soybean- wheat-soybean-tobacco), and cereal-sweet potato-tobacco (wheat-maize-wheat-sweet potato-wheat-sweet potato-tobacco). The life cycle assessment was used to calculate the carbon emissions and carbon footprint of these four cropping models. This study also clarified their composition and comprehensively evaluated the economic and ecological benefits of four crop rotation patterns by considering input costs and harvest output values.【Result】(1) The output value and profit ranking under different planting patterns were as follows: cereal-vegetable-tobacco>cereal-sweet potato-tobacco>wheat-maize-tobacco>cereal-soybean-tobacco. Additionally, the total cost of the grain-vegetable- tobacco model was significantly higher than that of the other three patterns. (2) The carbon footprint per unit area under different rotation patterns was as follows: wheat-maize-tobacco>cereal-sweet potato- tobacco>cereal-soybean-tobacco>cereal-vegetable- tobacco, with the value of 32 391.10, 31 042.64, 30 583.80, and 26 524.57 kg·hm^-2, respectively. The carbon footprint per unit yield for different crop rotation patterns followed this order: cereal-soybean- tobacco (0.51 kg·kg^-1), wheat-maize-tobacco (0.51 kg·kg^-1), cereal-sweet potato-tobacco (0.39 kg·kg^-1), and cereal-vegetable-tobacco (0.29 kg·kg^-1). The carbon footprint per unit output value of cereal-soybean-tobacco, wheat-maize-tobacco, cereal-sweet potato-tobacco, and cereal-vegetable-tobacco systems were 0.17, 0.17, 0.13, and 0.10 kg/yuan, respectively. (3) Fertilizer accounted for 50.6%, 56.4%, 57.2%, and 57.0% of carbon emissions in cereal-vegetable-tobacco, wheat-maize-tobacco, cereal-soybean-tobacco, and cereal-sweet potato-tobacco, respectively, making it the primary contributor to carbon emissions in each rotation pattern. The second largest contributor was tobacco curing electricity, which accounted for 15.2%, 14.5%, 13.5% and 13.0% in the above rotation patterns. 【Conclusion】Under the four crop rotation patterns, the cereal-vegetable-tobacco model demonstrated high economic benefits and low carbon emission. However, the input cost of this model was the highest, while the output value of tobacco was the lowest. Therefore, reducing labor input with improving tobacco benefits was crucial for promoting this rotation pattern in major tobacco producing areas. Tobacco of cereal-sweet potato-tobacco model had the highest output value and the lowest cost, but the high carbon footprint of this rotation pattern might be a constraint to the promotion. Fertilizer and tobacco curing electricity were the main sources of carbon emissions for each rotation patterns. Therefore, improving fertilizer utilization rate, and promoting clean energy barns to reduce the carbon footprint of tobacco leaf curing were the keys to reduce carbon emissions from various crop rotation patterns.

Key words: carbon footprint, carbon emission, crop rotation, tobacco, pepper, soybean, sweet potato, economic benefits, central Henan