丹江口水库农业面源污染特征研究

以丹江口市习家店小茯苓村为代表研究该流域的农业面源污染特性,在不同降雨强度下,收集不同土地利用方式下的农田地表径流,分析地表径流样品的污染物。结果显示,对于同一降雨强度和相似的植被覆盖度,其氮、磷流失量主要取决于土壤表层氮磷的含量。不同土地利用类型中总氮输出量差异显著(p0.05),表现为柑桔园玉米地蔬菜地;COD输出量表现为玉米地柑桔园蔬菜地;蔬菜用地中总磷输出量远远小于玉米和果树用地。不同土地利用类型中硝态氮是氮流失的最主要形态。径流污染负荷随降雨量的增大而增大;但污染物浓度与降雨量未呈现线性关系。从全年来看,秋季农田地表产流量及农田地表径流污染物输出量最大,这与该流域秋季降雨量及频繁的农事活动有密切关系。

Study on Characteristics of Agricultural Non-point Source Pollution in Danjiangkou Reservoir

In order to assess non-point source pollution from village around Danjiangkou reservoir,an experiment was conducted at Xiaofuling.The runoff samples were collected under different rainfall intensity to analyze influences of different land use types on pollutant load.The results show that under the same rainfall intensity and vegetation cover,different land use types represent different fertilization and tillage intensity,the nitrogen and phosphorus output in runoff depended on their content of the soil surface.The amount of total nitrogen output was significant different in different land use types,which was in the order of fruit trees maize vegetables.COD output expressed as maize fruit trees vegetables.TP output in vegetable land is much less than maize and fruit tree land.Nitrate-N was the main form of nitrogen loss in all the three land use types.The concentration of pollutants in runoff was not a linear relationship with rainfall,while the output of the pollutants in runoff loaded with the increase of rainfall.From the whole year perspective,the biggest fall of surface runoff and maximum pollutant output occurred in autumn,which were closely associated with rainfall and frequently agricultural activities in the period.