| Cite this article: | 李玖颖,吕纯波,卫 琦,等.典型降雨-稻田排水过程中氮素流失规律[J].灌溉排水学报,0,():-. |
| LI Jinying,LV Chunbo,WEI Qi,et al.典型降雨-稻田排水过程中氮素流失规律[J].灌溉排水学报,0,():-. |
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| Characteristics of nitrogen loss in typical rainfall-paddy drainage process |
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LI Jinying1, LV Chunbo1, WEI Qi2, WANG Haiyu2, CHEN Peng2, CHENG Heng2, XU Junzeng2
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1.Heilongjiang Irrigation Drainage and Water Saving Technology Cente;2.College of Agricultural Science and Engineering
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| Abstract: |
| 【Background】Rainfall is the main driving factor of nitrogen transfer from farmland to water body. It is of great significance to understand the drainage and nitrogen loss of farmland during the rainfall process.【Objective】To reveal the variations of nitrogen loss during typical rainfall-paddy drainage process, and provide a theoretical basis for making water-fertilizer management strategies to reduce agricultural non-point source pollution. 【Method】The variations of drainage water amount and its nitrogen (TN, NH4+-N and NO3--N) concentrations from paddy drainage were analyzed, based on the data during three typical rainfall (The rainfall is 56.2, 104.4 and 147.6 mm, rainfall duration is 9, 10 and 18 d, and the rainfall intensity is 5.1、10.4 and 8.2 mm/d) in the main growth period of rice in 2019 in Heilongjiang Province, which was collected by automatic flow monitoring-equal proportion water sample collection device.【Result】1. Generally, the paddy drainage increased with the increase of rainfall. Compared with the drainage volume (27.2 mm) in the first typical rainfall process, the drainage volume in the second and third processes were enhanced by 85.8% and 154.3%. Especially, the increase rate of drainage is greater than that of rainfall intensity. The maximum rainfall in the third typical rainfall process was increased 23.0% as compared to that in the first rainfall process, while the corresponding peak drainage rate of paddy field enhanced by a large degree of 85.3%. 2. Among three typical rainfall-paddy drainage processes, nitrogen concentrations showed the similar pattern with each other., that is, the concentration increased firstly then decreased gradually and finally tended to be stable. The concentrations of TN, NH4+-N and NO3--N in three paddy drainage maintained within ranges of 3.3-14.4 mg/L, 2.3-5.3 mg/L and 1.4-4.3 mg/L, all of them are below the IV standard of corresponding index of surface water quality. 3. TN, NH4+-N and NO3--N load during the second and third typical rainfall-paddy drainage processes were increased 1.7-4.6 kg/hm2, 0.7-1.9 kg/hm2 and 0.1-0.9 kg/hm2, in comparison with those in the first typical rainfall-paddy drainage process.【Conclusion】Agricultural non-point source pollution caused by excessive nitrogen in paddy drainage is the main risk pollution source of surface water quality during the main growth period (July to September) of rice in Heilongjiang Province. Avoiding fertilization before heavy rainfall and regulating paddy drainage period after rainfall will be helpful for reducing agricultural non-point source pollution. |
| Key words: rainfall; paddy drainage; nitrogen loss; load; agricultural non-point source pollution. |
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