青山湖流域不同地表覆盖降雨径流中氮磷流失过程研究

Research on Characteristics of Nitrogen and Phosphorus Loss under Different Coverage in Qingshan Lake Valley

在浙江省青山湖流域进行了不同地表覆盖类型野外模拟降雨实验,通过设定不同的坡度和降雨强度,综合分析流域内4种地表覆盖对降雨径流中氮磷流失的减少效果,结果表明:在相同雨强情况下,坡地径流中总氮浓度和氨氮浓度由高到低顺序均为:人工草地、次生林、荒草坡、竹林地。其中,总氮浓度曲线在各地表趋势均保持稳定,降雨强度的增大不影响4种覆盖度的顺序结果,但是人工草地与其他3种类型之间的浓度差值会随着雨强的增大而增大。在相同雨强情况下,坡地径流中总磷浓度由高到低顺序依次为:人工草地、次生林、荒草坡、竹林地。径流中速效磷浓度过程趋势与总磷浓度非常类似,而且随着雨强增大,速效磷占总磷比例也相应提高。

Experiments of artificial simulated rainfall were conducted in Qingshan lake valley of Zhejiang province. Different slopes and rainfall intensities were designed in experiments to analyze effects of four types of coverage on nitrogen and phosphorus loss in runoff. The analysis have come to the following conclusions： Under the same rainfall intensity in sloping field, the concentration of TN and NH4^＋-N in runoff were in order of the sequence ： artificial turf, forest, grassland to bamboo. Trends of TN concentration curve in four types remain stable, the increase of rainfall intensity does not affect the order of four types, but the difference between concentration of artificial turf and the other types increases with the increasing rainfall intensity. Under the same rainfall intensity in sloping field, the concentration of TP in runoff were in order of the sequence： artificial turf, forest, grassland to bamboo. The processes of TP concentration were very similar in runoff. With the rainfall intensity increased, the percentage of DP in TP also increased accordingly.