Measurement of soil surface roughness and estimation of water retention in surface depressions

The main objectives of this study were to investigate how rainfall energy affects soil surface microrelief and to calculate depressional surface storage from grid elevation data. Anon-contact laser profile meter was used to measure hight profiles of boxes filled with soil from the plough layer of a Chromic cambisol before and after simulated rain. The studied surface was thought to simulate a seedbed. Digital elevation models of the soil surfaces were developed with a resolution in hight of 0.25 mm and a grid spacing of 2 mm. Roughness indices, such as the standard deviation of hights, and the limiting slope and limiting difference, according to Linden and Van Doren (1986) were found to be sensitive to surface microrelief variations. Maximum microdepression storage was 1 mm for a horizontal initial surface, but was substantially reduced by subsequent rainfall.