山西省化肥投入区域分异及环境风险评价

Regional differentiation of chemical fertilizers input and environmental risk assessment in Shanxi Province

基于1985—2017年化肥施用量和作物播种面积,采用化肥施用环境风险评价模型,探讨了山西省化肥施用及环境风险的时空变化特征。结果表明,山西省化肥施用总量在1985—2017年间整体呈增加趋势,2017年山西省化肥施用强度为285.14 kg·hm^(-2),大多数地区农田化肥投入过量;其基本趋势是从晋北到晋南逐步增加,晋西北投入少、晋东南投入高。总化肥施用强度极值比为2.4,氮肥、磷肥和钾肥的极值比分别是1.9、2.7和3.4。全省11个地市氮磷钾投入比例是1:0.69:0.62,不尽合理。山西省2017年化肥施用环境总风险指数为0.52,呈低度环境风险;氮、磷、钾肥施用的环境风险指数分别为0.50、0.58和0.55。氮肥施用的环境风险处于安全状态;磷肥的环境风险区域集中在晋东南和晋中地区,钾肥的环境风险区域集中在晋东南和运城地区,均呈现中度、严重风险程度并有成片聚集特征。研究结果有利于调控山西农田施肥合理分布并进行分区指导,制定不同施肥方案,协调粮食增产和生态保护间的关系,为防治农业面源污染提供决策参考。

Based on the application amount of chemical fertilizer and the planting area of crops from 1985 to 2017,the spatial and temporal variation characteristics of chemical fertilizer application and environmental risk in Shanxi Province were investigated using the environmental risk assessment model of chemical fertilizer application.The results showed that the total amount of chemical fertilizer applied in Shanxi Province increased from 1985 to 2017 on the whole,and reached an application intensity of 285.14 kg·hm^(-2)in 2017.Most areas were overfed with chemical fertilizers.It showed a tendency of gradual increase from north to south of the province,with high input in the southeast and low input in the northwest.The extremum ratio of total fertilizer application intensity was 2.4,while the extremum ratios of nitrogen,phosphorus(calculated as P2O5)and potassium(calculated as K2O)were 1.9,2.7 and 3.4,respectively.The input ratio of nitrogen,phosphorus and potassium in the total 11 prefecture-level cities of Shanxi was 1:0.69:0.62,which was not reasonable.In 2017,the total environmental risk index of chemical fertilizer application in Shanxi was 0.52,showing a low level of environmental risk.The environmental risk indices of nitrogen,phosphorus and potassium fertilizers were 0.50,0.58 and 0.55,respectively.The environmental risk of nitrogen fertilizer application was in a safe state.The environmental risk areas of phosphate fertilizer were concentrated in Changzhi,Jincheng and Jinzhong,while the environmental risk areas of potassium fertilizer were concentrated in Changzhi,Jincheng and Yuncheng,where presented moderate to severe risk degree and were characterized by patchy aggregation.The results of the study are helpful for regulating the rational distribution of fertilization in farmland of Shanxi Province,giving regional guidance,formulating different fertilization plans,coordinating the relationship between grain production increase and ecological protection,and providing reference for the prevention and control of agricultural non-point source pollution.