Evaluation of soil conservation measures on a highly erodible soil in the Free State province, South Africa

Abstract

Soil erosion is a problem in South Africa, and is exacerbated by poor land use practices and erodible soils. Several methods are available to address the problem and a runoff trial was conducted over four rainfall seasons on an erodible, duplex soil. Various geotextiles and physical measures were evaluated. The treatments comprised jute matting, a synthetic geotextile, woven palm mats, micro-basins, surface stone rows and bare soil as the control. Runoff was recorded by a datalogger, with sediment load manually sampled after each rainfall event. All the treatments performed better than the bare soil, but there were several variations. Runoff was on average 38–63% less than that produced by the bare soil, whereas sediment load was on average 16–72% less. Re-establishment of vegetation cover was up to twice that of the bare plot. Approximation of soil loss showed reduction from an annual rate of over 50 t ha−1 to between 1 and 7 t ha−1 for most treatments. While many land users or communities may not be able to obtain or afford relatively expensive geotextiles, more basic treatments, requiring a lower level of inputs, are available as a cost-effective means of addressing the problem of excessive soil loss.