通过野外人工模拟降雨,研究丹江鹦鹉沟小流域不同土地利用类型的坡面地表径流和壤中流中氮素的流失特征,结果表明:径流小区降雨—地表径流过程总氮浓度平均值超过10mg/L,随着降雨历时的增加,全氮流失浓度大体呈现较平稳的状态,总体变化幅度不大。硝态氮浓度输出变化过程和总氮变化表现出良好的相关性,是氮素流失的主要形态;在大雨强条件下,农田小区壤中流氮素流失浓度均小于裸坡,其中农田全氮的流失量是裸地的1/2。在其他2种雨强条件下,农田小区壤中流除全氮外流失浓度均小于裸坡;壤中流中的氮素养分流失量占径流中比例较大,其中NO3--N表现最为明显,壤中流中NO3--N含量为9.09~11.42mg/L,最大比例为61.4%。
This article through the wild simulating rainfall,researching different type of land using of slope surface runoff and the loss of nitrogen in the shed soil.The results show that: Total nitrogen average is more than 10 mg/L in the process of rainfall runoff plots-surface runoff.Along with the increase of the rainfall duration,total nitrogen loss presents a more steady state,with a less overall change range.Concentration output of nitrate nitrogen has a good correlation with total nitrogen,is the main form of nitrogen loss;under the condition of the heavy rain,farmland of nitrogen loss in shed soil are less than the naked slope,half in the total nitrogen.In the other two kinds of rainfall intensity conditions,nitrogen loss of farmland soil area except totall nitrogen are less than naked slope in shed soil;the nitrogen loss in shed soil has a larger proportion in the runoff,specially nitrate nitrogen,the content of nitrate nitrogen is 9.09~11.42 mg/L in shed soil,and the largest proportion is 61.4%.