浙江舟山岛不同林分类型的水质效应

Effects of different forest types on water quality in Zhoushan Island,Zhejiang Province

为尽快恢复松材线虫病迹地的森林植被,充分发挥其生态功能,对浙江省舟山岛不同林分类型的降水、穿透水、树干径流、枯透水和土壤渗透水中的p H、Cl-、NO-3、SO2-4、Na+、Mg2+和K+等水质指标进行了检测。结果表明:1大气降水透过林冠层形成穿透水和树干径流后,p H持续下降,而Cl-等离子含量均有增加。枝叶与树干表面的吸附物是影响穿透水和树干径流水质的关键。2枯透水的p H大幅提高,说明枯落物层对水的p H具有较大的调节功能。SO2-4含量有所下降,说明枯落物层对SO2-4具有较大的吸附作用,而其他离子含量则有所提高,特别是NO-3和K+提高幅度较大,说明枯枝落叶经过微生物分解,NO-3和K+再次被水分淋洗出来。3相比枯透水,土壤渗透水的p H变化不大,Cl-、SO2-4、K+含量大幅下降,说明土壤层对Cl-、SO2-4、K+吸附较多。4阔叶林和混交林内水分的p H略高,枯落物层和土壤层是森林生态系统净化水质的关键所在。由于阔叶树枯枝落叶比针叶树更易分解,阔叶林中枯落物层和土壤层对离子的吸附能力超过针叶林,说明阔叶林和混交林净水能力更强。

In order to restore forest vegetation destroyed by pine wilt disease, make full use of its ecological function, water samples including atmospheric precipitation, through fall, stem flow, litterthrough and soil solution were collected from different type stand in Zhoushan Island. The pH and several ions such as Cl-, NO3- , SO42- , Na＋, Mg2＋, and K＋of water quality index were detected. The results showed that：①pH value decreased and contents of several ions increased in the process of the atmospheric precipitation forming throughfall and stem flow, thus adsorbate on the surface of branches, leaves and stems was the most important factor. ② pH value significantly increased in the process of through fall and stemflow forming litterthrough, therefore, litter layer has large regulation function on pH value. SO42- content decreased, so we could draw a conclusion that litter layer had a large adsorption effect on SO42- . Other ions contents increased, especially for NO3- and K＋, the reason was that NO3- and K＋ in the litter layer by microbial decomposition were leached out. ③pH values of litterthrough and soil solution were close, but content of Cl-, SO42- and K＋decreased significantly in the process of litterthrough forming soil solution. It could be concluded that soil layer had a larger adsorption effect on Cl-, SO42- , and K＋. Therefore, the litter layer and soil layer were the most important for purifing water of forest ecological system. ④ pH value of water in broadleaved forest and mixed forest was slightly higher than other forest types. Broadleaf litter was more prone to decompose than conifer, the ion adsorption efficiency of litter layer and soil layer in broadleaved forest was higher than that of conifer, so that we could conclude that water purification efficiency of the broadleaved forest and mixed forest was higher than coniferous forest.