【摘要】 以海河流域为研究区,基于化肥施用环境安全阈值预测模型及环境风险指数评价模型,对流域35个地级市农田氮磷施用强度及氮磷风险指数进行定量估算,并结合GIS空间分析能力,分析各地级市氮磷肥施用对环境污染的风险等级。结果表明,近11 a来,海河流域平均化肥施用强度为366.16 kg/hm2,是我国生态县化肥施用强度安全标准的1.46倍,是发达国家化肥施用安全标准的1.63倍。2005—2015年,氮、磷肥低度施肥区主要分布在流域西部,中度以上施肥区主要分布在中南部。从风险程度看,50%以上的氮磷肥处于尚安全区及低度风险区,中度以上风险主要分布在北京、天津及河北、河南、山西的个别地级市,但氮、磷肥风险在空间分布上存在显著差异;综合风险空间分布结果显示,90%以上为尚安全区及低度风险区,中度风险分布在朝阳市、天津市和新乡市。整体来看,流域化肥施用环境风险程度逐年降低,这与我国政府制定的较少农田化肥施用量的相关政策有必然的联系。更多还原

【Abstract】 Taking Haihe river basin as the research area, based on the environmental safety threshold prediction model and environmental risk index evaluation model for fertilizer application, the intensity and risk index of nitrogen and phosphorus application in the farmland of 35 prefecture-level cities in the basin were quantitatively estimated, and the risk level of environmental pollution caused by nitrogen and phosphorus fertilizer application in each prefecture-level city was analyzed in combination with GIS spatial analysis ability. The results showed that in the past 11 years, the average intensity of fertilizer application in Haihe river basin was 366.16 kg/hm2,which was 1.46 times higher than in the safety standard of chemical fertilizer application intensity in China’s ecological county, which was1.63 times higher than the safety standard of chemical fertilizer application in developed countries. From 2005 to 2015, the low-fertilization areas of nitrogen and phosphorus fertilizers were mainly distributed in the western part of the river basin, while the medium-level fertilization areas were mainly distributed in the south-central. From the perspective of risk, more than 50% of the nitrogen and phosphorus fertilizers were in the safe and low-risk areas. The risk areas of medium or above were mainly distributed in Beijing,Tianjin, and some prefecture-level cities in Hebei, Henan and Shanxi, but the spatial distribution of nitrogen and phosphorus fertilizer risk was significantly different. The spatial distribution of comprehensive risks showed that over 90% were still safe areas and low-risk areas, and the medium-risk areas were distributed in Chaoyang city, Tianjin city and Xinxiang city. On the whole, the degree of risk is decreasing year by year, which is inevitably related to the policies formulated by the Chinese government to reduce the application of agricultural fertilizer.更多还原