以贡嘎山海拔2900～3100m的暗针叶林生态系统为研究对象,分析了大气降水在穿透雨、树干径流、苔藓、土壤和地下水各个过程中干湿季和年际间离子含量变化特点。结果表明:(1)树干径流和穿透雨pH值小于降水,苔藓层可以有效的吸附酸性物质,土壤层酸性较强,森林区河流可以有效的缓解酸性物质;(2)森林区阴离子含量最高的是HCO3-,阳离子含量最高的是Ca2+,离子含量在干湿季的大小顺序不同。降水经过林冠后,除Na+外,离子含量值均呈现出明显的增大趋势,苔藓层对于K+、Ca2+、Mg2+有较强的吸附能力,土壤对于HCO3-的吸附能力较强;(3)苔藓、土壤和林区河流的N/P值均大于16,地表植被的限制因子是P;N、P在大气降水、穿透雨、树干径流、苔藓、土壤、地表水中的变化曲线相似,苔藓层N、P含量较高。

Within the dark coniferous with elevation from 2 900~3 100 m in Gongga Mountain,the variation characteristics of pH,ion content,TN,TP in precipitation,through-fall,stem-flow,swamp,soil and runoff are analyzed.The results indicated that:(1)because through-fall and stem-flow absorb amount of acid material,pH value increased;the swamp can absorb and deposit acid material,which makes water quality be better;when the water flow through soil,its pH value increased;surface water can dilute acid material;(2)the ion content of HCO-3 is the highest in negative ion,Ca2+ is the highest in positive ion,the content of total ions in dry and wet season is different.All the ion content is higher when drop through canopy except Na+,swamp have stronger absorb ability on K+,Ca2+,Mg2+,while soil can absorb more HCO-3,swamp and soil can purify water;(3)the ratio of N/P of swamp,soil and surface runoff in Gongga Mountain is more than 16,which indicated that the limited factor of vegetation is P;the variation curve of N,P in precipitation,through-fall,stem-flow,surface runoff,swamp,soil is similar,swamp have the highest N,P content.So,swamp and soil can leach and absorb lots of ion,N,P,which have the function of purifying water.