两种水稻生产方式的生命周期环境影响评价

以湖南水稻生产体系为例，应用生命周期评价方法，对两种水稻生产方式进行生命周期资源消耗与污染物排放清单分析，在此基础上进行了生命周期环境影响评价。结果表明，两种生产管理措施下潜在环境影响较大的均是富营养化、水体毒素、土壤毒素和环境酸化，其中传统生产方式下4项潜在环境影响指数分别为1．606、0．868、0．309和0．262，推荐生产方式下各项环境影响指数分别下降至1．277、0．489、0．260和0．211。经加权评估后，两种模式的生命周期环境影响综合指数分别为0．3634和0．2676。潜在富营养化主要来自于作物种植阶段农田NH3挥发和NO3-N淋失；水体毒素和土壤毒素主要来自农药使用；环境酸化主要来自施氮导致的NH3挥发和农用化学品生产中排放的SOx。水稻生产的管理方式需要在推荐生产方式的基础上做重大改进，实施清洁生产方式，减少氮肥、农药的使用量，是控制水稻生命周期环境影响的关键。

Assessment of the Environmental Impacts of Two Rice Production Patterns Using Life Cycle Assessment

Life cycle assessment（LCA）methodology was used to establish an inventory of resource utilization and emission and to further assess environmental impacts of rice with two management practices in Hunan Province, China. The results showed that the significant potential environmental impacts were aquatic eutrophication, fresh water ecotoxicity, terrestrial ecotoxicity and acidification in the two patterns. The impact indices werel.606, 0.868, 0.309 and 0.262 in conventional management practices （CMP） and 1.277, 0.489, 0.260 and 0.211 in recommended management practices （RMP）, respectively. The aggregate life cycle environmental impact index of rice with RMP was 0.267 6 in comparison with 0.363 4 for CMP. The eutrophication was mainly from NH3 voiatilization and NO3-N loss by using nitrogen fertilization. Freshwater ecotoxicity and terrestrial ecotoxicity mainly arose from pesticide use, and the aquatic eutrophication potential mainly from NH3 volatilization caused by using fertilizers in rice planting and SOx emission at the stage of agricultural chemicals production. The results implied that CMP need improved materially at the basis of RMP. Therefore, reducing nitrogenous fertilizer and pesticide consumption, developing energy- saving and clean production of fertilizers were the key ways to control the environmental impacts of rice production in China.