我国不同区域玉米施肥的生命周期评价

Life cycle assessment of fertilization in corn production in different regions of China

以吉林、陕西、河南、湖南、广西等玉米主产省份为例,以生产1t玉米为评价的功能单元,应用生命周期评价(LCA)方法,比较了不同生态区玉米生产过程中施肥的资源环境影响潜力.结果表明,五省环境影响综合指数大小依次为广西0.315、湖南0.309、河南0.273、陕西0.238、吉林0.183.几种资源环境影响中,潜力大小依次是富营养化、环境酸化、温室效应、土地利用和能源消耗,其中,施用氮肥引起的氨挥发是导致富营养化和酸化的主要原因.农户间玉米施肥的资源环境影响潜力差异很大,环境影响综合指数变异范围在41.2%～81.6%之间,且以湖南省最高,吉林省最低.如果将玉米追肥由撒施都改为穴施,五省的环境影响综合指数将降低8.5%～34.1%.总体而言,在目前生产条件下,吉林省具有资源环境影响较低的优势;富营养化是最主要的环境影响类型,而改进施肥方式、减少氨挥发是降低玉米施肥资源环境影响的关键技术途径.

In this paper,individual and integrated environmental impact indexes of corn fertilization in different ecological districts including Jilin,Shaanxi,Henan,Hunan and Guangxi provinces were investigated using Life Cycle Assessment（LCA）.For simplicity,emissions and consumed resources during corn production are calculated on the basis of producing 1 ton of corn grain.The results show that the integrated environmental indexes in these five provinces are in the order of Guangxi（0.315）,Hunan（0.309）,Henan（0.273）,Shaanxi（0.238） and（Jilin 0.183）.For the individual environmental impacts,the order is as follows： eutrophication acidification global warming land use energy depletion.In addition,the variance coefficients of integrated environmental indexes between farms in these five provinces largely range from 41.2%（i.e.Jilin） to 81.6%（i.e.Hunan）.NH3 volatilization from fertilization has been identified to be the most important contributor to eutrophication and acidification,and a change of fertilization method from top-dressing to deep application would lead a decrease of 8.5% ～ 34.1% in environmental indexes.In conclusion,under the current conditions,the corn production in Northeast China is associated with a lower environmental impact,and eutrophication is the most important environmental impact.Improvement of fertilization method to decrease NH3 volatilization is the most effective approach to reduce environmental influence.