Study On Temporal And Spatial Distribution Of Non-point Source Total Nitrogen In Shaying River Basin Of Fu Yang City Based On SWAT Model

This paper takes the Shaying River Basin in Fuyang City as the research object,and combines the DEM data,land use data,meteorological data,water quality and quantity data of the study area on the premise of non-point source pollution accounting in the study area through field investigation,data collection and water quality monitoring.The SWAT model was constructed and determined.The spatial and temporal distribution characteristics of non-point source total nitrogen in the Shaying River Basin of Fuyang City were discussed.The main results are as follows:1.The water quality of the Shaying River Basin in Fuyang City fluctuates greatly.In terms of time,spring and autumn are better than summer and winter.Rainfall is an important factor affecting water quality.The water quality index evaluation results show that the water quality index is at a moderate and good level in April each year,and the water quality index is in a poor level from July to September.2.The rainfall,runoff and total nitrogen loss from May to September accounted for more than 70% of the total annual research area,and rainfall and runoff showed strong correlation.The amount of total nitrogen lost has a significant seasonal variation and is strongly correlated with rainfall.The total nitrogen loss in the study area in 2012-2015 was 1167.16 t,1080.46 t,1839.39 t,and 1394.91 t,respectively.The total nitrogen loss intensity in 2012-2015 was 3.60-1.79kg/ha,and the annual average total nitrogen loss intensity is 5.99kg/ha,6.31kg/ha,6.72kg/ha,8.37kg/ha.Winter is the low valley period caused by non-point source pollution,and summer is the peak period of non-point source pollution.3.The total nitrogen loss intensity of each sub-basin in the four years from 2012 to 2015 is mainly concentrated below 8 kg/ha.The total nitrogen loss in the study area is more serious,namely,2,5,6,and 7 sub-basins,followed by 8,11 in the sub-basin,the lighter ones are 1,3,4,9,and 10 sub-basins.The total nitrogen loss intensity fluctuates greatly in different sub-basins.The neighboring sub-basins mostly exhibit similar characteristics of total nitrogen loss in the same year.The total nitrogen loss intensity during the flood seasons was significantly greater than that of non-flood season.Rainfall was the dominant factor affecting total nitrogen loss.Land use patterns and soil types were important factors affecting the loss of non-point source total nitrogen.4.The total nitrogen total loss coefficient shows a trend of increasing from north to south,and the spatial distribution of rainfall in the study area maintains a high consistency.The total nitrogen loss coefficient of total nitrogen in 2012-2015 was 0~0.720,0~0.683,0~0.770,0~0.904.The average total nitrogen loss coefficient of total nitrogen is 0.26,which has certain applicability in the Shaying River Basin of Fuyang City.Figure [47] table [20] reference [103]...