黄河流域农业面源污染时空变化及因素分析

Spatiotemporal evolution of agricultural non-point source pollution and its influencing factors in the Yellow River Basin

为探究黄河流域农业面源污染特点及有效治理措施,基于两次全国污染源普查数据,通过补充计算,分析了黄河流域污染物排放总量以及农业面源污染排放量的时空分布特点,探究了流域内各省份影响农业源污染化肥施用量、秸秆产生量和畜禽养殖等因素的时空分布情况以及污染治理效率,讨论了黄河流域面源污染针对性的治理对策。与2006年相比,2017年黄河流域污染物排放总量显著减少,农业源产生的化学需氧量、氨氮污染量占总污染量的比例显著增加,2017年农业源产生的化学需氧量、氨氮、总氮、总磷污染物排放量分别为96.2、1.2、7.9和1.1万t,污染量输出最大的省份为内蒙古,但单位耕地面积污染输出最大的两个省份为河南省和山东省。2017年黄河流域畜禽养殖是化学需氧量排放量的最直接影响因素,化肥是氨氮、总氮及总磷排放量的最直接影响因素,不同污染物指标与主控因子之间呈现显著的线性相关关系。与2006年相比,2017年流域内基础因素典型变化包括内蒙古耕地面积增加30%、流域内秸秆产生量及畜禽养殖猪当量分别增加46%和减少27%。河南、陕西、山东省份的单位面积化肥施用量过大,河南省的污染治理效率需要迫切提升。黄河流域农业面源污染治理应当采取全面治理政策及针对性污染治理策略相结合的方法进行,典型针对性措施包括加强陕西、河南以及山东省瓜果蔬菜化肥减量措施、西部地区牛羊养殖以及中东部地区猪养殖污染治理。

This study aims to investigate the temporal and spatial distribution of the agricultural nonpoint source of pollutant emission in the Yellow River Basin of China.The supplementary calculation was used to analyze the census data of the first and second pollution sources.Influencing factors were explored,including fertilizer usages,quantity of straw resources,pollutant loads from livestock and poultry breeding,and efficiency of pollutant treatment.The targeted prevention and control measures were proposed on the agricultural nonpoint source pollution in the Yellow River Basin.The results showed that:1)The total amount of pollutant emission in the Yellow River Basin decreased obviously in 2017,compared with 2006.The estimated total amount of chemical oxygen demand,ammonia nitrogen,total nitrogen,and total phosphorus pollutant were 1705,53,185,and 17 thousand tons,respectively,while the amount produced by agricultural production was 962,12,79,and 11 thousand tons.There was a significant increase in the proportion of agricultural nonpoint source pollution in the total amount.Inner Mongolia contributed the largest amount of agricultural nonpoint source pollution,but Henan and Shandong provinces presented the largest pollution intensity.Livestock and poultry breeding contributed the largest amount of chemical oxygen demand in 2017,whereas fertilizer was the main pollution source for the ammonia nitrogen,total nitrogen,and phosphorus pollutant.2)There was a significant linear relationship between different pollutant indices and control factors.The total amount of fertilizer usage increased 83%in Inner Mongolia in 2017,compared with 2016.The reason was that the fertilizer usage increased 41%per unit of the cultivated land,as the cultivated land increased 30%.Additionally,there were too many higher fertilizer usages per unit of the cultivated land in Henan,Shaanxi,and Shandong provinces,because of the large-scale planting of vegetables and fruits with substantial production,especially in Henan Province.3)Compared with 2006,the straw resources in the Yellow River in 2017 increased 46%with an amount of 0.113 billion tons,where most straw was produced in Inner Mongolia,due mainly to the largest cultivated land in the Basin and the large planting area of sugar and oil crops.In the number of straw resources per unit of the cultivated land,the top three were Henan,Shandong,and Ningxia Hui Autonomous Region.Specifically,the straw resources were attributed the most to the corn and wheat in Henan and Shandong provinces,while the corn was in Ningxia Hui Autonomous Region.4)The emission amounts from the livestock and poultry breeding decreased by 27%in 2017 than that in 2006,mainly because of the national policy on animal husbandry,such as no breeding areas.5)More efforts can be made to improve the efficiency of pollutant treatment for all pollution sources in Henan Province,and the fertilizer utilization rate in Shanxi Province.The overall control policy and the targeted strategies can be combined with the measures of agricultural nonpoint source pollution in the Yellow River Basin.The most effective measures can be adopted to control the fertilizer usages of vegetables and fruits in Henan,Shaanxi,and Shandong provinces,together with the comprehensive utilization of straw resources,such as corns in all provinces,and oil crops in Qinghai and Henan provinces and Inner Mongolia Autonomous Region.The treatment can be used to improve the utilization of livestock and poultry breeding,especially for cows and sheep in western provinces and pigs in the middle and lower reaches of the Yellow River.A better ecological cycle can be strengthened to combine planting with livestock and poultry breeding.