Microtopographic Influences on Soil Water Movement

Abstract

Site preparation of pine stands in the Piedmont often results in uneven microtopographic relief. Superimposed onto the macrotopography, microtopographic relief can strongly influence subsurface water content and movement (Keller et al., 1988). This study examines the relationship between microtopographic relief and soil moisture distribution in a loblolly pine plantation in the Piedmont of Georgia. Determination of the spatial distribution of soil moisture requires a topographic scale that encompasses the apparent variability in topography (Burt and Butcher, 1985). Thus microtopographic relief and its potential influence on soil water movement must be examined (Kirkby, 1988). Kirkby and Chorley (1968) identified hillslope hollows as areas where soil water convergence occurs. Soil water movement may be in the form of subsurface lateral flow (Anderson and Burt, 1978) or saturation excess overland flow (Burt and Butcher, 1985). Microtopographic depressions appear to behave hydrologically like hillslope hollows. Downslope movement of water through the leaf litter, over the soil surface, and laterally through the soil surface horizon could contribute to the concentration of water beneath the depressions. Preferential movement of water through the depressions could strongly influence both chemical and nutrient flux in the solum.