西安市水源地森林生态系统水质空间变化特征

Spatial Variation Characteristics of the Forest Ecosystem on Water Quality in the Water Source Area of Xi'an,China

在西安市供水水源地选择代表性天然林,对比分析森林生态系统各层次水样中化学成分质量浓度,探讨森林生态系统水质空间变化特征。结果表明:降水经过森林生态系统后,pH值升高,贡献较大者为土壤层。枯枝落叶层是吸收水中NO-3的关键层次;林冠层和土壤层是吸收NH+4的关键层次;森林生态系统各层次对K+均表现为淋溶,尤其是林冠层和土壤层;林冠层是吸收Na+和Ca2+的关键层次;枯枝落叶层是淋溶Mg2+的关键层次。林冠层和土壤层是吸附固定Cu2+、总Cr、Pb2+和Zn2+的关键层次;枯枝落叶层是固定Al3+的关键层次;土壤层对Cd2+表现为淋溶。

The investigation was conducted in the natural forest of Xi＇ an City water source area to analyze chemically for deter-mining the effects of different levels in the forest ecosystem on water quality. The results showed that after raining in the forest ecological system, pH increases and soil layer is the larger contributor. Litter layer is the key layer to absorb NO3, while the forest canopy and soil layer are the key layers to absorb NH4. In the forest ecological system, the performance for K＋ is leaching in forest ecosystem, especially in the canopy layer and soil layer. The forest canopy is the key layer to absorb Na＋ and Ca2＋, while the litter layer is the key layer to leach Mg2＋. The forest canopy and soil layer are the key layers to immobilize Cu2＋, total Cr, Pb2＋ and Zn2＋, while litter layer is the key layer to immobilize Al3＋. The soil layer for Cd2＋ is leaching.