中文摘要：

在全球淡水资源危机背景下,森林对水质的作用是森林水文学研究的核心问题之一.为研究亚热带缙云山森林生态系统水化学作用,在重庆缙云山选择了两个典型森林群落：马尾松×四川大头茶混交林（I1）和四川大头茶×四川山矾混交林（I2）,于2007到2010年期间,根据降雨与森林相互作用的空间顺序,采集大气降雨、林内雨、地表径流和壤中流,检验水体pH值和NO3-、SO24-、K＋、Na＋、Ca2＋、Mg2＋、Al3＋、Mn等8种离子的浓度.结果表明：缙云山降雨呈酸性,平均pH为5.43.林分I1枯落物层和土壤层对水体pH缓冲效果优于I2.I1对地表径流中Al3＋、Mn等有害元素的截留效果比I2好,且有效降低了NO3-这一水体富营养化因子随地表径流的输出.I1能够更好的截留壤中流的Mn,而对其中Al3＋截留效果更好的是I2.I2土壤与I1相比截留了更多壤中流的NO3-.

英文摘要：

At the background of worldwide deficiency of fresh water resources, the influence of forest ecosystem on water quality is one of the critical issues in research area of forest hydrology. In order to investigate the hydrochemical effects of subtropical forest ecosystem, two typical forest stands at Jinyun Mountain located in Chongqing were selected：Pinus massoniana Lamb × Gordonia acuminata Chang mixed forest （ typical forest I1 ） and Gordonia acuminata Chang × Symplocos setchuensis Brand mixed forest （ typical forest 12 ）. During 2007-2010, according to spatial sequence of interaction between precipitation and forest, rainfall, throughfall, surface runoff and interflow were collected and the pH value and concentrations of NO3^-, SO4^-, K^＋, Na^＋ , Ca^2＋ , Mg^2＋ , Al^3＋ and Mn dissolved in sampled water were examined. Results showed that rainfall in Jinyun Mountain area was acidic with an average pH value of 5.43. The acid-buffer abilities of litter and soil under typical forest 11 were better than those under 12. Pollutants in surface runoff（ NO3^-, Al^3＋ and Mn）were more effectively intercepted by I1, and the output of water eutrophication factor, NO3^- was notably reduced. 11 was more competitive in intercepting Mn in interflow while 12 was better at trapping Al^3＋. 12 had stronger ability to fix NO3^- in interflow.