典型降雨-稻田排水过程中氮素流失规律  

Nitrogen Loss with Rainfall Leaching from Paddy Field

作　　者：李玖颖 卫琦[2] 王海渝[2] 陈鹏[2] 程衡 徐俊增[2] LI Jiuying;WEI Qi;WANG Haiyu;CHEN Peng;CHENG Heng;XU Junzeng(Heilongjiang Irrigation Drainage and Water Saving Technology Center,Harbin 150040,China;College of Agricultural Science and Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]黑龙江省灌溉排水与节约用水技术中心,哈尔滨150040 [2]河海大学农业科学与工程学院,南京210098

出　　处：《灌溉排水学报》2020年第12期97-102,共6页Journal of Irrigation and Drainage

基　　金：中央高校基本科研业务费专项(B200201004)。

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/hm^2和0.1~0.9 kg/hm^2。【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。【Background】Leaching of rainfall from farmland is a main nitrogen loss pathway from soil to surface and subsurface water bodies,and understanding its underlying mechanisms is crucial to improving water and fertilizer management.【Objective】Focusing on paddy field,this paper investigated the variation in nitrogen loss with rainfall leaching aimed to provide guidance for improving water-fertilizer management and reduce nonpoint pollution in agricultural production.【Method】The experiment was conducted in a paddy field in 2019.In the experiment,we measured the variations in water drainage as well as the concentrations of nitrogen(TN,NH4+-N and NO3--N)during three rainfalls-56.2,104.4 and 147.6 mm that fell in 9,10 and 18 days,respectively,in Heilongjiang province.【Result】(1)The water drained from the paddy field following a rainfall increased with the rainfall depth.Compared with water drainage 27.2 mm from the first rainfall,water drainage from the second and third rainfalls increased by 85.8%and 154.3%respectively,indicating that the increase in water drainage was greater than the increase in the rainfall.The third rainfall was 23.0%more than the first one,but its associated water drainage from the soil was 85.3%more than that from the first one.(2)The nitrogen concentrations in the drainage water showed a similar pattern,increasing firstly followed by an asymptotic decline regardless of the rainfall events.The concentration of TN,NH4+-N and NO3--N associated with the three rainfalls varied in the range of 3.3~14.4,2.3~5.3 mg/L and 1.4~4.3 mg/L,respectively,lower than the requirements set by the IV Standard of Corresponding Index of Surface Water Quality.(3)The load of TN,NH4+-N and NO3--N in the drainage water associated with the second and third rainfalls increased by 1.7~4.6,0.7~1.9 kg/hm^2 and 0.1~0.9 kg/hm^2,respectively,compared with those in the first one.【Conclusion】Nitrogen leaching from the paddy field from July to September is a main source of the nonpoint pollution in agricultural pro

关 键 词：降雨 稻田排水 氮素流失 负荷 农业面源污染 

分 类 号：S28[农业科学—农业水土工程]