沈阳地区水稻生产的生态环境影响研究

为明确沈阳地区水稻生产对环境的影响,促进水稻清洁生产水平提升,采用生命周期评价法,以1 t稻谷为功能单位,对沈阳地区水稻生产系统的原料开采、农资生产和水稻种植阶段的10种潜在环境影响进行评价。结果表明,水稻生产对环境影响潜力较大的是水体毒性、富营养化、土壤毒性和人体毒性,环境影响指数分别为16.278、1.558、1.457和0.960。加权处理后,环境影响综合指数为2.267。水稻种植阶段化肥和农药的大量使用,增加了该阶段对环境酸化、富营养化、水体毒性和土壤毒性的影响潜值;其中化肥的大量投入,尤其是氮肥的大量投入,加重了其上游生产环节的能源消耗,从而提高了农资生产阶段对全球变暖的贡献率;而生产阶段能源的大量消耗又扩大了原料需求量,从而增加了原料开采阶段重金属排放量,使得潜在人体毒性成为原料开采阶段的主要环境影响。因此,减少化学肥料和农药的使用,是控制水稻生产潜在环境影响的关键。

Ecological and environmental impact of rice production in Shenyang, China

Identifying environmental impacts of rice production in Shenyang will provide significant references for local clean production standards. In this study, life cycle assessment(LCA)was applied to evaluate 10 potential environmental impacts(i.e., land use, water depletion, mineral depletion, energy depletion, global warming, acidification, eutrophication, aquatic toxicity, soil toxicity, and human toxicity)in the rice production system, and the functional unit was 1 ton of rice. The results showed that the parameters with significant environmental impacts during rice production were aquatic toxicity, eutrophication, soil toxicity, and human toxicity, with impact indices of 16.278, 1.558, 1.457, and 0.960, respectively. The general LCA index was 2.267 after weighted treatment. We found that the large-scale use of chemical fertilizers and pesticides in the arable farming stage increased the potential impacts of acidification, eutrophication, aquatic toxicity, and soil toxicity. The large input of chemical fertilizers, especially nitrogen fertilizers, had aggravated fossil energy depletion in its upstream production and increased the contribution rate of global warming in the agrochemical production stage. Furthermore, the large amount of fossil energy depletion in the agrochemical production stage increased the demand for raw materials, which increased emissions of heavy metals during the raw material extraction stage, resulting in human toxicity as the main environmental impact in this stage. Therefore, reducing the use of chemical fertilizers and pesticides is the key to controlling potential environmental impacts of the rice production system in Shenyang.