酸雨作用下中亚带森林冠层淋溶规律研究

2001年1月～2002年6月对韶山亚热带常绿阔叶林4个采样区进行了酸雨的监测,以监测数据为依据,分析研究了林内穿透水中主要离子的淋溶规律。结果表明:大气降水经过森林冠层后pH值明显升高,韶山亚热带常绿阔叶林对SO42-、NO3-、Mg2+、NH4+离子具有吸收作用,特别是NH4+和NO3-离子。SO42-、Ca2+和Mg2+离子的冠层淋溶百分率随降雨量的增加有明显减少的趋势。Ca2+、K+和Cl-随着pH的增加,其冠层淋溶百分率呈增加趋势。韶山地区在常年酸沉降作用下,森林冠层对酸性离子SO42-、NO3-的吸收作用最强。根据18个月离子浓度平均值来计算,韶山地区森林冠层离子的淋溶序列为:K+>Ca2+>Cl->Mg2+>SO42->NO3->NH4+>Na+。

Ionic Leaching of Subtropical Forest Canopies Under Acid Rain

The leaching law of major ions in forested acid precipitation in a subtropical forest was examined based on the experiment in four fields sampling sites in Shaoshan from January 2001 to June 2002. Results showed that pH value obviously increased and the ionic uptake evidences were proved by SO42-, NO3-, Mg2+ and NH4+, especially for NH4+ and NO3- when rain water passing through the canopies. The dissolved percentage of SO42-, Ca2+ and Mg2+ had the tendency to reduce with increase of the rainfall. Dissolved percentage of Ca2+, K+ and Cl- showed a tendency to increase along with increase of pH. Shaoshan forest canopies have the strongest effects on the uptake of SO42- and NO3- under acid rain. Ionic leaching order in Shaoshan forest based on the average ionic concentration of 18 months monitoring was K+ >Ca2+ >Cl- >Mg2+ >SO42- >NO3- >NH4+ >Na+.