【摘要】 从 1 997年 7月到 1 999年 8月 ,在庐山植物园选取针叶林和阔叶林各一片样地 ,对降雨、透冠水、干流水、渗漏水和地表径流进行了监测。结果表明庐山降雨 SO2 - 4浓度有升高趋势 ,1 998年降雨中 SO2 - 4浓度为 4 .2 1± 3 .4 8mg/ L。林冠对干沉降硫有吸收和截获作用 ,透冠水和干流水中 SO2 - 4明显高于雨水 ,针叶林中分别为 1 3 .68± 1 7.4 0 mg/ L和 1 5 .5 0±2 5 .2 0 mg/ L,阔叶林分别为 6.1 8± 6.3 7mg/ L和 7.3 5± 7.73 mg/ L,是森林中硫沉降的重要组成部分。针叶林地下水中SO2 - 4含量与雨水的显著正相关 (R2 =0 .75 8,n=6) ,与透冠水和树干流中 SO2 - 4含量之和极显著正相关 (R2 =0 .880 ,n=8) ,说明日本柳杉针叶林加重了硫沉降 ,对土壤中 SO2 - 4有较大影响 ;阔叶林的相关性都不显著 ,说明阔叶林虽然对SO2 - 4在土壤中的输入有所贡献 ,但相对作用较小。针叶林 SO2 - 4输入高而输出低 ;阔叶林输入低而输出高 ,可能处于稳态平衡。针叶林地表径流中 SO2 - 4含量受雨水影响较大 ,阔叶林中的则可能主要是土壤溶液中保存的 SO2 - 4持续淋洗的结果更多还原

【Abstract】 Sulfur translocation is one of the major issues concerning the biogeochemical cycling of sulfur in forest ecosystem under acid deposition.In China,acid deposition and its impacts on forest vitality and aquifer chemistry had been increased since 1980’s.Wet acid deposition has been a severe problem in Mt.Lushan,a famous tourist mountain with plant diversity reserve in subtropical region of Central China,for the last 20 years.In this paper,we report our study on sulfate in the forest ecosystem and its translocation dynamics associated with acid deposition. The field study was carried out in the forest within the area of Lushan Botany Garden,located in a relatively undisturbed forest valley with an elevation of 1100m a.s.l.Two plots were chosen for both broad leaf(dominated by Cornus controversa and L.glauca ,stand age over 10a)and need leaf forest(dominated by Crypomeria japonicum, stand age 30~40a)at the two separate sides.From July,1997 to August,1999,in site monitoring of water fluxes and concentration of sulfate was performed seasonally.Facilities for collecting water samples of through fall(TF),stem flow(SF),soil percolate(SP),seepage(SE)and surface runoff(SR)were implemented under forest on site.Precipitation water was collected on a open site.The sulfate in water was determined by turbidimetry.Sulfate concentration in precipitation appeared 4 21±3 48mg/L,being remarkably higher than that reported in 1987.Sulfate in TF and SF was 13 68±17 40mg/L and 15 50±25 20mg/L respectively under needle leaf forest stands,and 6 18±6 37mg/L and 7 35±7 73mg/L respectively under broad leaf forest stand.There were significant relationships between the seasonal mean of soil solution and of atmospheric precipitation( R 2 0 758, p <0 05),and between that of soil solution and of forest precipitation (SF+TF)( R 2 0 880, p <0 01)in needle leaf forest stand.Owing to the leaf type,the needle leaf forest actually received bigger amount of sulfate and discharged less in contrast to the broad leaf forest.This might explain much higher degree of sulfate accumulation and soil acidification stress in needle leaf forest stands under acid deposition impacts.Sharp variability of sulfate concentration in runoff under need leaf forest implicated a prompt response of aquifer S to the deposition.However,relatively stable sulfate discharge was found under broad leaf forest.Therefore,it is necessary to understand the S biogeochemistry in forest under acid deposition for illustrating the effects of vegetation sulfate retention on ecosystem S translocation and aquifer S chemistry.更多还原