Effect of slope and plant cover on run-off, soil loss and water use efficiency of natural veld.

Abstract

Reports the results of a study conducted to investigate the effect of slope and basal cover on run-off and soil loss on natural veld occurring on a Valsrivier soil form; Run-off and soil loss were monitored from a climax, subclimax and pioneer veld, each on a 5,9%, 4,1% and 2,1% slope, by means of a rainfall simulator on a Valsriver soil form. With rainfall intensity, soil moisture content at the beginning of each rain storm, and soil texture the same for each treatment, plant cover and composition had a significant (positive) (P<0,05)influence on the amount of soil loss and run-off that occurred, as against the insignificant influence of the slope. An average of 6,2t/ha soil loss and 80,6% run-off of the amount of water applied occurred from the pioneer veld (0,7% basal cover) on the steepest slope. In all the successional stages more run-off and less soil loss occurred from wet soil than from dry soil. Significant (P<0,01) relationships between basal and canopy cover were obtained with run- off and soil loss. The climax, subclimax and pioneer veld produced on average 0,57g, 0,23g and 0,07g aboveground phytomass for each litre of water evapotranspirated

Keywords: basal cover; canopy cover; composition; erosion; moisture content; Natural veld; phytomass; plant cover; rainfall; relationships; run-off; slope; soil loss; soil moisture; soil texture; south africa; Valsrivier soil forms; water use efficiency

Journal of the Grassland Society of Southern Africa.