Stabilization of drifting sands using micro silica-lime-clay mixture as a mulch

Providing durable mulches with improved resistance using cheap materials in order to stabilize drifting sands is very important. Micro silica is one of these materials which in combination with lime and clay can offer resistant mulches. In the present study, different mixtures of micro silica-lime-clay were used as mulches. In all treatments, the amounts of 200 g clay and 10 g lime were used as the basic composites of mulches and micro silica was added at 0, 1, 5, 10, 15, and 20% of clay dry weight. Generally, six different mixtures were obtained at three replicates and four parameters including surface soil shear strength (SS), penetration resistance (PR), soil losses (SL), and threshold friction velocity (V) were measured on samples after 7 and 60 days. Results showed that the application of micro silica in clay-lime mixture increased SS, PR, and V significantly, so that the increase in measured parameters depended on the applied micro silica rates. The more the micro silica rates, the greater decrease in soil erosion, so that the soil losses at a wind speed of 15 ms(-1) decreased 100 times at the rates of 5, 10, 15, and 20% of micro silica and no losses were observed at these rates in comparison with control situation (0%). More improvements occurred in the mentioned properties of mulches during time. The application of 200 g clay, 10 g lime, and 20 g micro silica after 60 days was the best composition for improving the studied mulches resistance.