喀斯特山区坡面土壤水分变异特征及其与环境因子的关系

    Variability of soil moisture and its relationship with environmental factors on Karst hillslope

    • 摘要: 为探明土地利用方式、地形、微地貌等环境因子对喀斯特山区土壤水分空间变异的影响,应用植被数量生态学中的去趋势典范对应分析方法(DCCA)在一典型坡面上研究了表层(0~15 cm)土壤水分变异特征及其与环境因子的数量关系。研究结果表明,在取样时段内坡面土壤质量含水率均值介于21.36%~32.58%之间,季节变化明显,均呈现中等变异特征。不同土地利用方式下土壤水分随时间的变化趋势一致,均呈明显的“四峰型”波动,土壤平均含水率以自然植被最高,撂荒地和坡耕地次之,人工林最低。DCCA的排序结果显示,土层深度、有机碳含量、土地利用方式和裸岩率对坡地土壤水分变异及其季节变化的影响最为显著,土壤体积质量和坡度的影响次之,坡位和海拔的影响最小。鉴于喀斯特坡面地形及微地貌的复杂性,后续研究还需要加大采样间隔和密度,并综合考虑坡向、坡面曲率、汇水分布面积等因素对土壤水分变异的影响,并结合各土地利用方式下土壤养分状况,探讨适应喀斯特坡地退化生态系统修复的农业工程措施和生态重建模式。

       

      Abstract: The aim of the experiment is exploring the influence of environmental factors, such as different land uses, topography and microgeomorphology, on the variability of soil moisture on Karst hillslope. The method of detrended canonical correspondence analysis (DCCA) was used to analyze surface soil moisture (0–15 cm) variability and its relationship with environmental factors on a typical hillslope in Karst region. The results showed that surface soil moisture ranged from 21.36% to 32.58% during the whole sampling periods, and had seasonal changes with middle variability. Soil moisture in different land uses had similar changes with time accompanied with four peak types. Soil moisture was the highest in natural vegetation field, followed in abandoned field and sloping field, and the lowest was in artificial forest. The DCCA ordination analysis indicated that soil depth, soil organic carbon, land use and bare rock ratio had the biggest effects on soil moisture variability and seasonal pattern on the hillslope. Soil density and slope had the less effects, and vertical position and height had the least effects. The sampling spacing and density of soil moisture should be increased, and aspect, curvature, upslope contributing area should also be considered in further studies according to the special physiognomy of Karst hillslope. Furthermore, these results suggested that combined with the soil nutrient characteristics of different land use on the hillslope, some feasible agricultural engineering measures and vegetation restoration modes should be developed on the degraded ecosystems on Karst hillslope in the future.

       

    /

    返回文章
    返回