不同雨强下坡地氮流失特征  

Research on characteristics of nitrogen loss in sloping land under different rainfall intensities

作　　者：吴希媛[1] 张丽萍[1] 张妙仙[2] 倪含斌[1] 王辉[1] 

机构地区：[1]浙江大学环境与资源学院,杭州310029 [2]浙江林学院环境科技学院,临安311300

出　　处：《生态学报》2007年第11期4576-4582,共7页Acta Ecologica Sinica

基　　金：浙江省自然科学基金项目资助(401005);国家教育部重点实验室环境修复与生态健康基金资助项目(EREH-050401)~~

摘　　要：试验采用模拟降雨手段,对总氮、铵氮和硝氮流失量过程曲线及三者的浓度百分比变化规律进行分析总结,获得以下结论:(1)降雨过程中,随着降雨强度的增加,氮流失的浓度和流失总量都会相应增加,在覆盖度较小时,雨强对氮流失浓度和流失总量起决定作用。(2)径流量随时间延长的增加趋势十分明显,径流中流失的总氮浓度随着时间延长没有明显变化,但是流失量却呈上升趋势。铵氮和硝氮流失浓度随着时间的变化规律,主要表现为径流前期浓度较高,随着降雨时间的延长,浓度趋于稳定或减小,后期则又有所上升。(3)与"蓄满"、"超渗"两种径流方式相对应,氮流失类型也有两种:坡地产生"蓄满"径流时,氮流失中可溶性氮流失较多;坡地产生"超渗"径流时,则氮流失中不可溶性氮流失所占比例增加,但是两种情况下,均是以可溶性氮流失为主,其中又以硝氮流失所占比例最大。坡度较小的情况下,次降雨过程中,不溶性氮占总氮流失量的百分比随时间延长而增加。Non-point source pollution has been one severe environmental problem over world and was concerned and studied actively. Developed agriculture brought on the loss of fertilizer and pesticide which include much nitrogen and phosphorus. These contaminations led to the eutrophication of water body. However, there are several main factors affecting nitrogen loss such as rainfall intensity, slope, coverage ratio and so on. The factors effected nitrogen loss mainly by influencing runoff, in other words, the polluting ways of nitrogen loss to water would be reflected by nitrogen loss trend in runoff under different conditions. In order to simulate the nitrogen loss characteristics during crops natural growing processes, according to given conditions such as rainfall intensity, slope and coverage, the experiments of adopting artificial simulated rainfall were designed. The experiments were conducted from August in 2005 to January in 2006 and carried in WSBRZ type automatic control glasshouse in Zhejiang University. There were two wooden runoff troughs with slopes 14 and 21, and they were filled with soil which was taken from Qingshan lake valley in Linen city. Cabbages were planted to provide different coverages based on the experiment design. In each rainfall process, 15 runoff samples were collected separately per minute or every two minutes in order. Following on, the runoff samples of 15 were analyzed in the lab, and the concentrations of TN, NH4^＋ - N and NO3^- -N were respectively measured in 24 hours. Artificial simulated rainfalls of 15 were conducted during the whole experiment. According to the experiment purpose, 6 rainfalls were selected from 15 simulated rainfalls and separated into three groups, while each group has two rainfalls with same slope and coverage and different rainfall intensities. Then, experiment data were analyzed in two ways. Firstly, by charting the curve of nitrogen loss in each group with increasing time, the gradients and numerical values of curves on the same chart were compared w

关 键 词：面源污染 降雨 径流 氮流失 

分 类 号：X592[环境科学与工程—环境工程]