模拟酸雨对果园土壤交换性阳离子迁移及其对土壤酸化的影响

Effects of Simulated Acid Rain on Exchangeable Cation Transplant and Acidifying Potential in Litchi Orchard Soils

采用短期室内淋溶的方法研究了模拟酸雨对供试果园土壤交换性Ca2+、Mg2+、K+、Na+、交换性盐基总量(BS)、阳离子交换量(CEC)、电导率(EC)等变化的影响。试验结果表明,土壤交换性Ca2+(pH2.5)、Mg2+、K+、Na+、BS(pH2.5)、CEC(pH≥3.5)含量较酸雨淋溶前增加,且随着剖面深度表现出较好的层次性;淋出液中C a2+、Mg2+、K+、Na+含量随着模拟酸雨酸度的增强而依次增加,其中pH2.5酸雨处理与其它淋溶处理间淋出液Ca2+、Mg2+、K+、Na+含量差异显著;以土壤交换性Ca2+、BS、CEC、盐基饱和度(BSP)与EC为指标衡量土壤的酸化,pH 2.5酸雨处理导致了淋溶土柱表层和中间土层的土壤酸化,其中交换性Ca2+、BS、BSP指标表征pH 3.5的酸雨处理引起了表层土壤酸化,而pH≥4.5的酸雨淋溶缓冲了土壤的酸化,土壤的酸度减弱。

Through short-term indoor leaching, the effects of simulated acid rain on soil exchangeable Ca^2＋, Mg^2＋ ,K^＋ ,Na^＋, base saturation （BS） ,CEC,electrical conductivity （EC） contents in litchi orchard under consideration were studied. It was shown that Ca^2＋ , Mg^2＋ ,K^＋ ,Na^＋ concentrations in leachates increased with the increment of pH of the simulated acid rain, and significant differences between pH 2.5 and the other pH treatments were found; After leaching, soil exchangeable Ca^2＋ （pH2.5）,Mg^2＋ ,K^＋ ,Na^＋ , BS（pH2.5）,CEC（pH≥3.5）contents were increased compared with those before leaching, and there existed a good distribution feature with depth of soil layers. Adopt the first kind acidification indexes, the simulated acid precipitation pH 2.5 caused the tested soils acidification;By adopting soil exchangeable Ca^2＋ , BS,CEC, base saturation percentage （BSP） or EC as acidification indexes, respectively, acid rain with pH2.5 caused the tested soils acidification in the surface layers and middle layers; in which, the indices of exchangeable Ca^2＋ ,BS or BSP showed the acidifying effect of pH 3.5, but acid rains with pH≥4.5 played a buffering role to soils tested, with the weakening of soil acidity.