Abstract:Soil water holding capacity of plantations established on severely eroded lands was studied in tropical region of South China. Four plantations representing a chronic series of restoration, including barren land, Eucalyptus forest, mixed broad-leaved plantation and secondary natural forest, were compared. Soil bulk density, water holding capacity and soil porosity were determined. The results showed that barren land with little vegetation cover had high soil bulk density (>1.5 g cm-3), and Eucalyptus plantation established on barren land made soil hardened and the water holding capacity became worse partly because of litter removal by villagers. Replacement of Eucalyptus plantation with mixed broad-leaved plantation markedly increased the water holding capacity of soil. Soil bulk density (0~40 cm) of the mixed broad-leavedf plantation was below 1.3 g cm-3 , and the total porosity was 46.1%～51.4%,and their non-capillary porosity were 15.0%～22.7%. The maximum water storage of the soil (0～40 cm) was 1892 t hm-2, a level similar to those of many other broad-leaved forests. The secondary natural forest located nearby had a better water-holding capacity than the mixed broad-leaved plantation. The surface soil bulk density was only 1.07 g cm-3, and the total porosity was 58%, and the maximum water-holding capacity was 538 g kg-1. Compared to those in 1983, mixed broad-leaved plantations largely improved soil physical properties with lowered soil bulk density and enhanced water-holding capacity. However, soils of barren land and Eucalyptus plantation had changed little, with hard surface soil and low water holding capacity. The results indicated that establishment of highly diversified plantation could enhance water infiltration and water holding capacity of soil.
