通过模拟酸雨实验,研究了缙云山马尾松×四川大头茶×四川杨桐混交林(林分Ⅰ)、广东山胡椒×四川山矾混交林(林分Ⅱ)、毛竹林(林分Ⅲ)、四川山矾×杉木混交林(林分Ⅳ)、马尾松林(林分Ⅴ)、灌丛(林分Ⅵ)枯落物淋滤液的化学性质。结果表明:①6种典型林分的枯落物淋滤液pH值均随模拟酸雨pH的降低而减小;林分Ⅴ的枯落物层对模拟酸雨pH值的缓冲效果最好。②6种典型林分枯落物淋滤液中的盐基离子(Ca2+、Mg2+、K+、Na+、NH+4)浓度随模拟酸雨pH值的降低而增加。在pH值2.7和3.5的强酸雨作用下,林分Ⅴ枯落物淋滤液中的盐基离子浓度均是最高的,达到了0.143 6 mmol/L和0.074 0mmol/L,在pH值4.5的酸雨作用下,林分Ⅱ枯落物淋滤液的盐基离子浓度是最高的,达到了0.138 9mmol/L。③在模拟酸雨pH值为2.7时,6种典型林分淋滤液中Al3+、Fe、Mn、Zn急剧增加,且林分Ⅴ枯落物淋滤液中Al3+(0.018 2 mmol/L)、Fe(0.004 4 mmol/L)、Mn(0.010 7 mmol/L)、Zn(0.002 5 mmol/L)均高于其他林分,林分Ⅴ更易受到这几种元素的毒害。
The hydro-chemical properties of litter layers of 6 typical forests including Pinus massoniana×Adinandra bockiana×Gordonia acuminata Chang mixed forest(forest type Ⅰ),Lindera kwangtungensis×Symplocos setchuanensis mixed forest(forest type Ⅱ),Phyllostachys pubescens forest(forest type Ⅲ),Symplocos setchuanensis×Cunninghamia Lanceolata(forest type Ⅳ),Pinus massoniana forest(forest type Ⅴ) and shrub forest(forest type Ⅵ)in Jinyun mountain were studied by the simulated acid rain experiment.The results showed: ①Litter leaching pH values of 6 typical forest stands reduced with the decrease of pH of simulated acid rain.The acid buffer ability of litter layer in forest type Ⅴ was best.②Base cation(Ca2+,Mg2+,K+,Na+,NH+4) concentrations of all 6 typical forest litter leaching increased with the decrease of pH of simulated acid rain.Under the eluviation of different simulated acid rain(pH value: 2.7,3.5),the base cation concentrations of litter leaching of forest type Ⅴ were always largest: 0.143 6 mmol/L(pH 2.7),0.074 0 mmol/L(pH 3.5).Under the eluviation of pH 4.5 simulated acid rain,the base cation concentrations of litter leaching of forest type Ⅱ were the largest: 0.138 9 mmol/L.③The concentrations of Al3+,Fe,Mn,Zn in litter leaching of 6 typical forest stands increased dramatically when the pH value of simulated acid rain was 2.7.And the concentrations of Al3+(0.018 2 mmol/L),Fe(0.004 4 mmol/L),Mn(0.010 7 mmol/L) and Zn(0.002 5 mmol/L) in forest type Ⅴ litter leaching were larger than that of the others.It indicated that forest type Ⅴ was more vulnerable to these toxic elements.