西苕溪流域土地利用对氮素径流流失过程的影响

采用野外实验地人工模拟降雨方法,研究了浙江省西苕溪流域不同土地利用类型的土壤氮素径流流失过程。研究结果表明,土地利用类型深刻地影响着径流及其氮流失的过程,各种土地利用类型的产流时间、径流增长率、积累径流量和氮的流失过程均有明显差异:相同降雨条件下,产流所需时间菜地最长,其余依次为稻田、竹林、草地和桑园;径流增加及积累径流量最大的是稻田,其它依次为桑园、竹林、草地和菜地;各种土地利用类型径流中有效态氮浓度与降雨时间具有很好的相关性,可以用不同的方程式进行模拟。

Effects of Land Use in Xitiaoxi Catchment on Nitrogen Losses from Runoff

More and more attention has been paying on water pollution causedby nutrients, such as nitrogen and phosphorus and so on. It is necessary to study the mechanisms of nitrogen and phosphorus losses of runoff so as to establishdistribution model of transporting nutrients and, if possible, to calculate theamount of their losses accurately. It has been indicated that land exploitationhas affected the courses of nitrogen losses deeply from the data of rainfall simulation experiment in Xi Tiao Xi Catchment. As for the time of generating runoff, it is the longest under vegetable field, followed by rice field, bamboo field, grass field and mulberry field. While the greatest rate of runoff increasing and the whole amount of runoff is under rice field, and then mulberry field, bamboo field, grass field and vegetable field respectively. Furthermore, the variation courses of effective nitrogen concentration under different land use types can be simulated with different models since the relation between those course andrainfall time.