京郊典型作物生产体系施肥环境影响的生命周期评价

以北京市顺义区冬小麦-夏玉米轮作和露地蔬菜两种作物生产体系为对象,采用生命周期评价（LCA）方法,综合考虑全球变暖、环境酸化、水体富营养化、土壤毒性、能源消耗和淡水资源消耗6种环境影响类型,分别以年产1t作物产品干物质和种植1hm2作物为评价功能单元,系统研究了施肥的资源环境影响潜力。结果表明：对于大田作物和露地蔬菜生产系统,年产1t产品（干物质）施肥的综合环境影响指数分别为0.46和2.11,种植1hm2作物施肥的综合环境影响指数则分别为4.74和26.77;农田种植环节环境影响潜力的贡献分别占大田作物和露地蔬菜整个生命周期环境影响潜值的95.1%和99.1%,远远大于肥料生产环节;大田作物和露地蔬菜生产过程中的环境影响潜力均表现为水体富营养化〉环境酸化〉全球变暖〉淡水资源消耗〉能源消耗〉土壤毒性;肥料氨挥发是引起水体富营养化和环境酸化的主要途径,硝态氮和总磷的淋洗径流损失也是水体富营养化的主要来源。优化施肥量是控制作物生产施肥潜在环境影响的关键。

Life Cycle Assessment of Environmental Impacts by Fertilization in Major Cropping Systems of a Peri-urban Area of Beijing, China

The environmental impacts（ including the depletion of non-renewable resources, depletion of fresh water, global warming, soil toxi- city, acidification and aquatic eutrophication ） of fertilization in the winter wheat-summer maize and open-field vegetable production systems in Shunyi District were evaluated using a life cycle assessment（LCA ） method. The above environmental impacts of the entire life cycles（ including the exploitation of raw material, fertilizer production and plant cultivation sectors ） were evaluated on the basis of 1 t of dry-weight crop grain produced and 1 hm2 of arable land used, where the crop yields and farmers＇ resources for the assessment were obtained from the surveys conducted during the period of 2008/2009 and 2009/2010. Large difference in the environmental impact among the winter wheat-summer maize and open-field vegetables systems were obtained, where the integrative indicators on the basis of 1 t of dry weight crop grain and 1 hmz farmland for the winter wheat-summer maize system were 0.46 and 4.74, but 2.1 l and 26.77 for the open-field vegetable systems. While from the view point of different sectors along the life cycle processes, in comparison with the sectors of the exploitation of raw material and fertilizer production, the plant cultivation sector was identified as the largest contributor to the environmental impact, which accounted for 95.1% and 99.1% of the integrative impacts in the winter wheat-summer maize and open-field vegetable production systems. Furtherumre, the six envi- ronmental impacts of the both cropping systems was in a rank of aquatic eutrophication〉acidification〉global warming〉fresh water depletion〉 energy depletion〉soil toxicity. The contribution of fertilization within a crop production cycle to the eutrophication was mainly attributed to the ammonia volatilization, nitrate leaching and phosphorus leaching and runoff related to the application of fertilizers; The ammonia volatilization associated to N fertilization was also observed to be responsible for the soil acidification. It was concluded that optimizing the fertilization rate（organic and inorganic fertilizer） in the crop production systems was the key to reduce the environmental impacts of the win- ter wheat-summer maize and open-field vegetable production in China.