| 引用本文: | 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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| 摘要: |
| 【目的】揭示典型降雨-稻田排水-氮素流失规律，为通过合理制定水肥管理策略减少农田面源污染排放提供理论依据。【方法】以黑龙江省2019年水稻主要生育期（7—9月）内3次典型降雨（降雨量、降雨历时和降雨强度范围依次为56.2~147.6 mm、9~18 d和5.1~8.2 mm/d）过程为研究对象，通过流量自动监测-等比例水样采集装置对典型降雨过程中稻田排水流量进行监测，并在相应时段内对水样进行等比例（排水流量的1/105）采集，分析了典型降雨对稻田排水及其氮素（TN、NH4+-N和NO3--N）流失的影响。【结果】（1）稻田排水量随降雨量的增大而增加，与第1次降雨过程中的稻田排水量（27.2 mm）相比，第2次和第3次的排水量增大了85.8%和154.3%。且排水速率的增加速率远大于降雨强度的增加速率，第3次典型降雨过程中的最大降雨量较第1次典型降雨过程中的值增加了23.0%，但其相应的稻田排水速率峰值却增大了85.3%。（2）典型降雨-稻田排水中的氮素质量浓度在降雨后呈先增大后减小并趋于稳定的趋势，3次典型降雨-稻田排水中的TN、NH4+-N和NO3--N质量浓度范围依次为3.3~14.4、2.3~5.3 mg/L和1.4~4.3 mg/L，均处于地表水水质相应指标IV标准以下。（3）与第1次典型降雨-稻田排水过程中的氮素负荷相比，第2次和第3次稻田排水中的TN、NH4+-N和NO3--N负荷分别增加了1.7~4.6、0.7~1.9 kg/hm2和0.1~0.9 kg/hm2。【结论】稻田排水中过高的氮素所导致的农业面源污染排放是黑龙江省水稻主要生育期（7—9月）地表水的主要污染源，避免在强降雨前施肥，并调整降雨后排水时间有助于降低农业面源污染排放。 |
| 关键词: 降雨；稻田排水；氮素流失；负荷；农业面源污染 |
| DOI： |
| 分类号:S28 |
| 基金项目:中央高校基本科研业务费专项(B200201004) |
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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. |
