黔中典型喀斯特地区土壤水分时空特性分析

土壤水分是岩溶山区植被恢复和生态环境建设的关键性限制因素。利用黔中喀斯特普定石漠化研究基地的采样分析数据,用回归模型分析了不同利用类型（坡面、洼地）0～50cm土壤水分的动态变化规律;探讨了土壤水分空间变化的影响因子。结果表明,坡面和洼地土壤水分呈现弱变异特征,其中坡面土壤水分变异程度相对较大,变程分别是30.4～24.5和30.4～26.2。在剖面上,两者的垂直变异趋势大致相反,坡面土壤水分变异系数随土层的加深而增大;而洼地由于受外界自然条件的干扰相对较小,变异系数随着土层深度的增加而减小,而且其中的不同土地利用类型都是在40～50cm处达到最小。研究显示,植被覆盖度提高后土壤总体上朝着有利于水分保蓄和植被恢复的方向转变。

Space-time characteristics of soil moisture in the central Guizhou typical karst area

Soil moisture is the critical factor for vegetation rehabilitation and ecological environment construction in karst mountainous region. Sampling data from the Puding Stone-Desertification Research Base in central Guizhou is used in the paper. The Regression Model is used to analyze the regime of the soil moisture between 0~50cm under different land-use style（slope, depression）. The impact factor on spatial variation of the soil moisture is also studied. The results show that soil moisture on the slope and in the depression pre- sent weak mutation characteristics and the vertical variation on the slope is contrary to that in the depression approximately. It is found that soil moisture on the slope increases with the soil depths and variation extent is relatively larger than that in the depression. The variation ranges are 30.4-24. 5cm and 30. 4-26. 2cm. There are some differences in vertical variation under different land-use types. The coefficient of variation decreases with the soil depths. Both of them reach the lowest between 40 and 50cm. On the whole, the research shows that with the increase of the vegetation coverage the soil becomes more beneficial to water conservation and vegetation restoration.