祁连山排露沟流域不同水文过程水体氮素含量特征

Nitrogen Content Characteristics of Water Bodies in Different Hydrological Processes in Pailugou Basin of Qilianshan

为探明祁连山排露沟流域不同水体中全氮、铵态氮和硝态氮的空间分布特征,本研究在祁连山排露沟流域青海云杉林内对大气降水、穿透雨、树干茎流和河川径流水等不同水文过程中的水样进行采集,测定不同水体中全氮、铵态氮和硝态氮含量。结果表明,研究区内不同水文过程水体的全氮、铵态氮和硝态氮含量在首次产生树干茎流时,全氮和铵态氮含量均呈现出:树干茎流>穿透雨>大气降水>河川径流,硝态氮含量则呈现出:河川径流>树干茎流>穿透雨>大气降水。其他降水事件中不同水体氮素含量的差异显著性没有明显的变化规律。河川径流中的全氮和铵态氮含量均值明显低于大气降水、穿透雨和树干茎流中的全氮和铵态氮含量,但河川径流的硝态氮含量均值明显高于大气降水、穿透雨和树干茎流中的硝态氮含量。相关性分析表明,有机碳与全氮和铵态氮之间均呈极显著正相关(p<0.01),而有机碳与硝态氮的相关性不显著(p>0.05)。

In this study,the Pailou Basin of the Qilianshan was selected as the research area,and water samples were collected from Picea crassifolia forest in different hydrological processes,such as atmospheric precipitation,throughfall,stemflow and river runoff water.Typical rainfall events were selected for collection and indoor measurement,and the contents of organic carbon,total nitrogen,ammonium nitrogen and nitrate nitrogen in different water bodies were determined.It provides scientific basis for nutrient management and water purification function of forests ecosystems in the Qilianshan.The results showed that the contents of total nitrogen,ammonium nitrogen and nitrate nitrogen in water body of different hydrological processes in the study area were in the order of stem flow>penetrating rain>atmospheric precipitation>river runoff when stem flow first occurred.The contents of nitrate nitrogen were in the order of river runoff>stem flow>penetrating rain>atmospheric precipitation.There was no obvious pattern of change in the significance of differences in nitrogen content of different water bodies in other rainfall events.The mean values of total nitrogen and ammonium nitrogen contents in river runoff were significantly lower than those in atmospheric precipitation,throughfall and tree trunk stem flow,but the mean values of nitrate nitrogen contents in river runoff were significantly higher than those in atmospheric precipitation,throughfall and tree trunk stemflow.Correlation analysis showed that there was a highly significant positive correlation between organic carbon and both total and ammonium nitrogen(p<0.01),while the correlation between organic carbon and nitrate nitrogen was not significant(p>0.05).