长江中下游稻-麦轮作系统生命周期环境影响评价——以江苏南京为例

长江中下游地区是我国稻麦主产区,辨析该区农业生产过程的环境效应,可为实现农业绿色发展提供理论指导。以稻麦轮作典型生产区江苏南京为例,应用生命周期评价方法对该系统生命周期的资源消耗和污染物排放清单进行分析和评价。结果表明:在该稻-麦轮作体系中,水稻生命周期的环境影响主要是富营养化、水体毒性、环境酸化和土壤毒性,环境影响指数分别为2.32、0.76、0.33和0.27;而小麦生命周期的环境影响主要为富营养化、水体毒性、土壤毒性和环境酸化,环境影响指数分别为2.50、2.09、0.32和0.23。肥料、农药、柴油的生产和使用是引起能源消耗和气候变暖的主要因素;农户超量施用氮肥是造成潜在环境酸化和富营养化的关键;农药的使用是造成水体毒素和土壤毒素的最主要原因;而氮肥和农药投入对人类毒性均有较大影响。因此,在工业领域加快新型能源开发,实施清洁生产;在农业领域优化田间管理措施(如减少氮肥施用、研发多功能一体化农机及推广低毒高效农药)能有效控制长江中下游地区稻麦生产负面环境影响,提高该区农业可持续发展能力。

Life Cycle Environmental Impact Assessment on Rice Winter Wheat Rotation System in the Middle and Lower Reaches of Yangtze River:A Case Study of Nanjing,Jiangsu Province

The middle and lower reaches of the Yangtze River is the main area for rice and wheat producing in China. To clarify the environmental effects of agricultural production in this area can provide theoretical guidance for the realization of green agricultural development. In this study, we analyzed and evaluated the resource consumption and pollutant emission inventory of rice winter wheat rotation system in Nanjing, Jiangsu based on a method of life cycle assessment. Results indicated that the major environmental effects of the life cycle in rice season were eutrophication, water toxicity, environmental acidification and soil toxicity, with the environmental impact indices of 2.32, 0.76, 0.33 and 0.27, respectively. While in wheat season, eutrophication, water toxicity, soil toxicity and environmental acidification were the major environmental impacts, with the environmental impact indices of 2.50, 2.09, 0.32 and 0.24, respectively. The production and use of fertilizers, pesticides and diesel oil were the main factors for energy consumption and climate warming. The key to the potential environmental acidification and aquatic eutrophication were the excessive nitrogen fertilizers application by farmers. The input of pesticides was the main cause of potential water ecotoxicity and soil ecotoxicity, and the input of nitrogen fertilizers and pesticides both have a greater impact on human toxicity. As a result, the negative environmental impact can be effectively controlled by development of new energy sources and implement cleaner production in the industrial field, and optimizing field management (such as reducing the application of nitrogen fertilizer, developing multi functional integrated agricultural machinery and promoting low toxicity and high efficiency pesticides) in the middle and lower reaches of the Yangtze River.