典型降雨事件下流域氮素输出特征与影响因素研究  

Study on the characteristics and influencing factors of nitrogen output in watershed under typical rainfall events

作　　者：刘新茹 杜新忠 刘晓荣 雷秋良[1] 刘宏斌[1] LIU Xin-ru;DU Xin-zhong;LIU Xiao-rong;LEI Qiu-liang;LIU Hong-bin(State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China/Changping Soil Quality National Observation and Research Station/Key Laboratory of Non-point Source Pollution Control,Ministry of Agriculture and Rural Affairs Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081;College of Soil and Water Conservation,Beijing Forestry University,Beijing 100083)

机构地区：[1]中国农业科学院农业资源与农业区划研究所,农业农村部面源污染控制重点实验室/北京昌平土壤质量国家野外科学观测研究站/北方干旱半干旱耕地高效利用全国重点实验室,北京100081 [2]北京林业大学水土保持学院,北京100083

出　　处：《中国环境科学》2025年第2期1027-1035,共9页China Environmental Science

基　　金：国家重点研发计划(2022YFC3204001);国家自然科学基金项目(42107076,U20A20114)。

摘　　要：为探究降雨事件下流域尺度氮素的输出特征及影响因素,在2022年和2023年洱海上游凤羽河流域开展了6场典型降雨事件水质水量监测,分析氮素随降雨-产流的变化及输出特征,明确雨强、历时、流量等因素对氮素负荷的影响机制.研究结果表明,降雨前期土壤条件较湿润的情况下,更容易造成较大的降雨产流,并且会在降雨等级达到大雨(3级)时引起氮素浓度的较大波动,说明氮素的流失会受降雨等级的影响.降雨事件的不同阶段的分析表明,中雨及以下降雨事件中,氮素主要在降雨后期流失,约占整场降雨的62.25%~78.77%,但降雨前期单位时间氮素流失量大;在大雨及以上降雨事件中,氮素中期流失占比达一半以上,且单位时间氮素流失降雨中期最大.降雨-产流过程因子与氮素流失的冗余分析表明,氮素浓度变化与负荷流失主要与前期降雨量指数(API)呈显著正相关关系,其次受平均雨强(RI)、最大30min降雨(I30)和峰值流量(FP)等因素的影响.其中氨氮(NH_(4)^(+)-N)和硝酸盐氮(NO_(3)^(-)-N)则与总流量(FA)、降雨历时(RT)、总降雨量(RA)的相关性比较大;而溶解态有机氮(DON)与API相关性较大,与其它因素相关性较弱或表现为负相关.In order to explore the characteristics and influencing factors of nitrogen export at the watershed scale during storm events,this study carried out water quality and quantity monitoring of six typical storm events in the Fengyu River Watershed in the upper subbasin of Erhai Lake in Basin 2022 and 2023.The changes of nitrogen export during rainfall-runoff process and the influence mechanism of rainfall intensity,duration,flow and other factors on nitrogen load were investigated.The results indicated that it was more likely to cause larger rainfall runoff when the antecedent soil moisture was highter in the early stage of rainfall event.A large fluctuation of nitrogen concentration was observed when the rainfall intensity reached heavy rain(level 3),indicating that the loss of nitrogen is affected by the rainfall intensity.The analysis of different stages of rainfall events showed that nitrogen was mainly lost in the late stage of the event,accounting for about 62.25%~78.77%of nitrogen load during the whole event,but the amount of nitrogen loss per unit time was large in the early stage of rainfall.For heavy and extreme events,the proportion of nitrogen loss in the middle period was more than 50%of nitrogen load during the whole event,and the nitrogen loss per unit time was the largest in the middle period of the event.Redundancy analysis of rainfall-runoff process and nitrogen loss factors showed that nitrogen concentration change and load export were mainly positively correlated with Antecedent Precipitation Index(API),followed by average rainfall intensity(RI),maximum 30-minute rainfall(I30)and peak flow(FP).Among them,ammonia nitrogen(NH_(4)^(+)-N)and nitrate nitrogen(NO_(3)^(-)-N)were significantly correlated with total discharge(FA),duration of rainfall(RT),and total rainfall(RA).However,dissolved organic nitrogen(DON)has a greater correlation with API and a weaker or negative correlation with other factors.

关 键 词：氮素 降雨事件 流域尺度 

分 类 号：X142[环境科学与工程—环境科学]