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| Response characteristics of nitrogen concentration in farmland and irrigation ditches in the Yellow River water diversion irrigation area of Ningxia |
| Received:April 23, 2024 |
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| KeyWord:irrigated area;nitrogen;paddy field;dryland;spatio-temporal characteristics |
| Author Name | Affiliation | E-mail | | LIU Xiaotong | Agricultural Resources and Environment Institute of Ningxia Academy of Agriculture and Forestry Science, The Key Laboratory of Soil and Plant Nutrition of Ningxia, Yinchuan 750002, China | | | SUN Yuan | Ecological Environment Monitoring Center of Ningxia Hui Autonomous Region, Yinchuan 750002, China | | | ZHAO Ying | Agricultural Resources and Environment Institute of Ningxia Academy of Agriculture and Forestry Science, The Key Laboratory of Soil and Plant Nutrition of Ningxia, Yinchuan 750002, China | | | LUO Jianhang | Agricultural Resources and Environment Institute of Ningxia Academy of Agriculture and Forestry Science, The Key Laboratory of Soil and Plant Nutrition of Ningxia, Yinchuan 750002, China | | | MA Ying | Agricultural Resources and Environment Institute of Ningxia Academy of Agriculture and Forestry Science, The Key Laboratory of Soil and Plant Nutrition of Ningxia, Yinchuan 750002, China | | | ZHANG Tianpeng | Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China | | | LIU Huan | Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China | | | ZHANG Xuejun | Agricultural Resources and Environment Institute of Ningxia Academy of Agriculture and Forestry Science, The Key Laboratory of Soil and Plant Nutrition of Ningxia, Yinchuan 750002, China | | | LEI Qiuliang | Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China | leiqiuliang@caas.cn |
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| Abstract: |
| In view of the unclear response mechanism of irrigation and drainage of farmland and water quality of different types of ditches, nitrogen migration of different levels of ditches, and the response mechanism of shallow groundwater and surface water of different types of farmland, this study takes typical paddy fields and drylands in Qingtongxia irrigation area of the Yellow River irrigation district of Ningxia as an example, and adopts field monitoring method combined with agricultural management measures to analyse the response relationship between the nitrogen concentration of different types of agricultural fields and ditches at different levels, and to clarify the characteristics of the temporal and spatial changes of nitrogen and the influencing factors of different types of agricultural fields, in order to provide a theoretical theory for the reasonable control of nitrogen non-point source pollution in Yellow River basin. The results show that on a temporal scale, the total nitrogen in paddy fields and dryland at different levels of ditches responds significantly to fertilization and irrigation, and the peak concentration of total nitrogen can generally be reached within 7-9 days after fertilization. The total nitrogen concentration in different levels of ditches showed that paddy field surface water>dryland agricultural ditch>combat ditch>paddy field agricultural ditches>submerged ditches, and the nitrogen concentration in paddy field agricultural ditches, dryland agricultural ditches, and combat ditch all show the characteristics of upstream>midstream>downstream. With the increase of groundwater burial depth, the total nitrogen concentration decreases and presents the characteristics of upstream>midstream>downstream. The response relationship between the total nitrogen concentration of shallow groundwater and that of surface water is delayed by 2-5 days. There is a positive correlation between nitrogen flux in fields and different levels of ditches, and a clear response relationship exists between shallow groundwater, irrigation water, surface water, farm ditches, ditches for preventing flooding and ditches for irrigation. By properly controlling water and fertilizer inputs, managing groundwater levels, reducing agricultural nitrogen output, and preserving ditch water while not affecting drainage in the fields, the wetland ecological effects of ditches can be effectively utilized to reduce nitrogen concentrations, and nutrients can be maximized within the field system for recycling, thereby effectively controlling nitrogen surface runoff pollution caused by field drainage. |
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