Beneficial effect of palm geotextiles on inter-rill erosion in South African soils : field trials

Abstract

Geotextile mats made of woven palm leaves showed potential using a rainfall simulator for their effectiveness in reducing surface runoff and sediment load from a range of South African soils and mine tailings. This paper advances that research by using field plots to evaluate and quantify the palm mats on a larger scale. Plots at four localities (Bergville, Ladybrand, Roodeplaat and Mabula) were used. Results showed that average runoff under the palm mats decreased by between 0% and 70% at Bergville, and by between 0% and 7% at Ladybrand, compared to bare soil. Sediment load under the mats decreased by between 0% and 7% at Ladybrand, and by between 3% and 9% at Roodeplaat, for three different combinations of slope, mat density and mat mesh size. At Roodeplaat, splash erosion decreased by between 62% and 6%, while at Ladybrand and Mabula, re-vegetation increased by between 3% and 0%. Organic carbon content and topsoil surface levels also increased under the mats. Organic, bio-degradable, easy to manufacture geotextiles, such as palm leaf mats, show much potential, especially in combining employment opportunities with enhanced environmental protection in many susceptible areas of South Africa.