Soil pore characteristics of evergreen and deciduous forests of the tropical monsoon region in Cambodia

Both evergreen and deciduous forests (Efs and Dfs) are widely distributed under similar climatic conditions in tropical monsoon regions. To clarify the hydraulic properties of the soil matrix in different forest types and their effects on soil water storage capacity, the soil pore characteristics (SPC) were investigated in Ef and Df stands in three provinces in Cambodia. Soils in the Ef group were characterized in common by large amounts of coarse pores with moderate pore size distribution and the absence of an extremely low K(s) at shallow depths, compared to Df group soils. The mean available water capacity of the soil matrix (AWC(sm)) for all horizons of the Ef and Df group soils was 0.107 and 0.146 m(3) m(-3), respectively. The mean coarse pore volume of the soil matrix (CPV(sm)) in the Ef and Df groups was 0.231 and 0.115 m(3) m(-3), respectively. A water flow simulation using a lognormal distribution model for rain events in the early dry season indicated that variation in SPC resulted in a larger increase in available soil water in Ef soils than in Df soils. Further study on deeper soil layers in Ef and each soil type in Df is necessary for the deeper understanding of the environmental conditions and the hydrological modelling of each forest ecosystem. Copyright (C) 2010 John Wiley & Sons, Ltd.