桂林会仙实验基地石灰土剖面化学组成分布的研究

Research on Vertical Distribution of Chemical Composition in Lime Soil Profile in Huixian,Guilin

西南岩溶地区灰岩风化成土速度慢,石灰土土层浅薄,理化性质分异不明显,但在岩溶动力系统的作用下,石灰土对环境变化有着同样的敏感性,而土壤水恰能反映石灰土的这种敏感性。所以,对石灰土-土壤剖面化学组成的研究应同时将土壤和土壤水加以考虑。为阐述岩溶区石灰土及其土壤水化学组成在剖面的垂直分布特征和地质、环境意义,以及这两个载体之间存在的区别和联系,对广西桂林会仙试验基地的石灰土壤剖面及其土壤水进行了采样分析。结果表明,该地石灰土物理化学性质尚未产生分层分异,成壤改造进行缓慢,土壤成熟度低;土壤水化学组成垂直变异系数远远大于土壤,岩溶作用、生命活动、降水等多变因素对土壤水有着显著的影响;在水的长期作用下,土壤元素分布呈现出和土壤水相同的整体性质。即洼地土壤和土壤水的Ca、Mg含量较坡地低,而K、Na、Fe、Zn、Mn、Cu、B等含量较坡地高,这是地貌条件控制下元素迁移的结果。

Limestone weathered into soil slowly in karst region in the southwest. The lime soil is thin and its difference of physical and chemical properties is not obvious. The lime soil is sensitive to the environment changes under the karstifieation. So soil water should be analyzed as well as lime soil in the study on lime profile. In order to understand the distribution characteristics of chemical composition in lime soil and soil water,and get the information they provided, two typical karst landform, karst depression and hillslope,were choose as study objects, and two soil profiles were established on them. The results showed that coefficient of variation chemical composition in soil water were much higher than soil; soil water eould be affected by the environmental factors which are changeable significantly,like karstification, precipitation, etc;both in soil and soil water, content of Ca and Mg on depression was lower than hillslope ,meanwhile,content of K,Na,Fe ,Zn,Mn,Cu and B on depression was higher than hiUslope. This indicated that the distribution of elements in soil and the soil water of the same feature as a whole, because of long-term eluviation.