Effect of Soiltac on wash erosion by overland flow of some Trinidadian soils

A laboratory facility was built and used to test the wash erosion from three Trinidadian soils (a sandy loam, clay loam and clay), after application of a soil stabiliser (Soiltac) at four concentrations and when exposed at four slopes (9%, 15%, 21%and 30%) for four overland flow durations (5, 10, 15 and 20 min). The concentrations include control (0%), the ’manufacturer’s recommended application rate for different slopes, and 2% by volume more and less than these recommended rates. The aim of the test was to identify, quantify and explain the effect of Soiltac on the soil erosion process. Intermediary measurements of runoff were made to describe how Soiltac affects the soil erosion process and the implications of its use. Mean runoff rates increased from 15.85 mm min−1 in the control soil with no Soiltac to 16.20 mm min−1 for the soil with Soiltac at 30% slope. Adding Soiltac to the soil decreased mean wash erosion rates at 30% slope from 0.206 kg m−2 min−1 for the control soil to 0.001 kg m−2 min−1 for the soil with the highest application rate of 19% by volume, showing that Soiltac has the capability of eliminating soil erosion on slopes. Soiltac increased runoff rates irrespective of soil slope, soil type and overland flow duration. Wash erosion was greatest in the sandy loam followed by clay and the clay loam soils. This occurred irrespective of slope, duration of overland flow or concentration of Soiltac. Results from this study show that although Soiltac greatly decreases soil erosion, since it also increases runoff, its use in agricultural fields should be limited. It may be best used in slope stabilisation and dust control works in road construction as well as in construction sites, with the adequate provision of drainage facilities.