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| Spatial-temporal changes of nitrogen and phosphorus non-point source pollution in Hetao Irrigation District based on SWAT |
| Received:June 05, 2023 |
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| KeyWord:SWAT model;Hetao irrigation district;total nitrogen;total phosphorus;non-point source pollution;pollution source |
| Author Name | Affiliation | E-mail | | YI Shaorong | School of Water Conservancy and Ecological Engineering, Nanchang Institute of Technology, Nanchang 330099, China
Key Laboratory of Basin Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | | | FENG Xuejiao | Nanjing Piesat Information Technology Co., Ltd, Nanjing 210012, China | | | WANG Zongwei | Jiangsu Province Surveying and Mapping Engineering Institute, Nanjing 210013, China | | | XIONG Junfeng | Key Laboratory of Basin Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | jfxiong@niglas.ac.cn | | LIN Chen | Key Laboratory of Basin Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | | | XIA Yu | School of Water Conservancy and Ecological Engineering, Nanchang Institute of Technology, Nanchang 330099, China | | | WU Hanyi | Key Laboratory of Basin Geography, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth of Chinese Academy of Sciences, Beijing 100875, China
Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China | |
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| Abstract: |
| In the context of the gradual intensification of agricultural activity, effective identification of key pollution sources and regions can mitigate the negative impact of non-point source pollution. Taking Hetao Irrigation District as the research area, a SWAT model was used to estimate the nitrogen and phosphorus load of the irrigation area and to analyze the spatial distribution characteristics and interannual variation in non-point source pollution. The key areas and sources of non-point source pollution were identified. The average annual loads of total nitrogen and total phosphorus, from 2001 to 2020, were 565.23 and 108.93 kg·a-1, respectively. The zone of high pollutant loading was mainly distributed in the middle of the irrigated area, and the low nitrogen loading zone was mainly distributed in the northern part of the irrigated area. In the study period (2001-2020), the nitrogen and phosphorus load from non-point sources showed a trend of first rising and then decreasing in the central region, first decreasing and then increasing in the western region, and decreasing in the eastern and northern regions. Domestic sewage in the irrigated area accounted for the largest contribution of nitrogen and phosphorus, at 44.51%, followed by cropping (28.76%) and animal breeding (26.73%) sources. The relative contribution rate of cropping sources was affected by the change in rainfall; the water quantity gradually decreased from Wulat Front Banner Station in the east to Hangjin Back Banner Station in the west. The contribution rate of planting source was higher in the east than in the west. If pollutant loading is to be reduced, domestic sewage as the greatest source of pollution needs to be strictly controlled. The management focus should be on the the disposal of toilet feces and urine into septic tanks or similar systems in order to convert harmful substances into biogas slurry and other useful inputs for cropping. |
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