不同利用方式下红壤坡地土壤水分时空动态变化规律研究

利用连续3年土壤水分定位观测数据，研究了红壤坡地不同利用方式下土壤水分的时空动态变化规律。结果表明：土壤水分时空动态变化主要受降雨和植被类型的影响。土壤水分季节变化分为相对稳定期、消耗期和补给期三个时段；土壤剖面（0～90cm）水分含量从表层到深层表现为增长型，依据2003年土壤水分标准差和变异系数。将土壤剖面划分为活跃层、次活跃层和相对稳定层3个层次；土壤剖面水分变异系数随降雨量和土层深度的增加而减小，随植被根系的增长而变大。平水年，深根系区与浅根系区土壤水分变化差异表现在30cm深度以下，而丰水年其差异主要表现在土壤表层（0～30cm）；无论平水年还是丰水年，深根系区土壤水分变幅均比浅根系区大。

Spatio-Temporal Dynamic Change of Soil Water in Sloping Land with Different Use Modes in Red Soil Region

Based on fixed observation on the sloping land in red soil region during 2002~2004,spatio-temporal dynamic change of soil water with various land use types were analyzed.The results showed that the dynamic change of soil water content was affected by precipitation and vegetation primarily,and its seasonal change had three stages: relative stabilization,consumption and supplement stage.Soil water content(0~90 cm) increased with the increase of soil depth.Based on the standard deviation and variation coefficient of soil water content,the soil profile could be divided into three layers generally: the active,the sub-active and the relatively steady layer.The variation coefficients decreased with increasing precipitation and soil depth,but increased with the increasing vegetable roots.The large differences on soil water between deep-root and shallow-root plant plots could be seen in the surface layer(0~30 cm) in rainy year, but under 30 cm depth in average year.The variation ranges of soil water in the deep-root plant plots were wider than those of shallow-root plant plots.