西藏酸性土壤交换性盐基状况及其变化特点

根据西藏 9个土类 76个土壤剖面的分析资料 ,探讨酸性土壤的交换性盐基状况及其变化趋势。结果表明 ,供试土壤各交换性盐基离子饱和度的变化 ,在总体上与其盐基饱和度 (BS)及其所制约的pH变化一致 ,但BS及 pH的变化主要归因于Ca2 + 饱和度的变化 ,而受Mg2 + 、K+ 、Na+ 饱和度变化的影响小。各交换性盐基的组成比例 ,总体上也都随BS和pH而变化 ,但Ca2 + 的比例呈正向变化 ,变幅较大 ,而Mg2 + 、K+ 、Na+ 呈负向变化 ,变幅较小 ,这在BS或 pH低值区表现更为明显

The Status of Exchangeable Base and Its Characteristic Change of Acid Soils in Tibet

According to the analysis data of 76 soil profiles of 9 soil great groups in Tibet, exchangeable base and change trend of acid soil are discussed. The results indicate that the change of BIS (Base Ion Saturation) is the same as those of BS and pH (which is decided by BS) generally. The change of BS and pH are mainly attributed to the change of Ca~(2+), but little affected by the change of Mg~(2+), K~+, Na~+. As a whole, the compositive percentage of each exchangeable base ion varies with BS and pH. The ratio of Ca~(2+) is in positive relation with that of BS and pH, and the change range is broad, on the contrary, the compositive ratio of Mg~(2+), K~+, Na~+ is negative relation with that of BS and pH, and the change range is narrow, especially in the soil with low values of BS and pH.