关键词: 高产粮区, 面源污染, 生命周期评价, 污染风险

Abstract: The Life cycle Assessment (LCA) method has been an effective tool to evaluate negative externalities of agro-ecosystems. Here, it is used to comprehensively predict and evaluate potential non-point source pollution risks of grain production in high-input high-output grain production areas, starting with the sources of external input of the agricultural system. Huantai County of Shandong, in North China Plain was selected as a case for study. Results show that under the winter wheat-summer maize rotation system, which is a typical farming system in North China Plain,for of non-point source pollution, eutrophication potential (EP) ranks first and is followed by aquatic ecotoxicity potential (AEP), and acidification potential (AP). Cultivation of summer maize is much higher in all the three indices, and what is more, EP and AEP of the cultivation of summer maize and EP of the cultivation of winter wheat all exceeded the world’s per capita environmental impact potentials of the year of 2000. The complex non-point source pollution potential risk Index(I_P) of the cultivation of winter wheat and summer maize, iwas 1.08 and 1.45, respectively, and obviously the latter is 34% higher than the former. Under the winter wheat-summer maize rotation system, the crop of summer maize contributes more than the crop of winter wheat to non-point source pollution. Application of nitrogen fertilizer contributes 99.75% and 88.06%, respectively, to AP and EP, and application rate of pesticides determines size of AEP. Based on the fertilizer application rate recommended in the nutrient management optimization programme for agricultural non-point source pollution comprehensive management techniques demonstration zones, it can be predicted that the I_P of the crop of winter wheat and of summer maize may decrease by 2.91% and 18.35%, respectively, nevertheless, the latter is still higher than the former inI_P. Therefore, it can be assumed that the practice of reducing input of nitrogen fertilizer and pesticide is the key to control of agricultural non-point source pollution.

Key words: high-yield farmland, non-point source pollution, life cycle assessment, pollution potential