Abstract

The objective of this study was to evaluate the effect of soil conditioners and man-made erosion control materials on stabilization of sloping hills using rainfall simulator and small flume facilities. Treatments were man-made erosion control materials (from polypropylene fabric) and soil conditioners (gypsum and PAM), these treatments were evaluated on a soil sample with a clay texture taken from a hill having 15 to 30% slopes. Soil surface were subjected to 3 simulated rainstorm including 25, 50 and 75 mm h^-1. Runoff and sediment loss rates were determined in different times for 60 min after initiation of runoff. Man-made erosion control materials were reduced sediment concentration and runoff intensity between ranges of 4 - 82% and 0 - 8% respectively compared with the bare soil.  Also, amending soil surface with soil conditioners did not reduce runoff significantly compared with the control on steep slopes. Appli-cation of soil conditioners alone had low efficiency. Whereas application of high levels of conditioners reduced soil loss to non detectable levels as compared with the control treatment. Obtained results from measurements of aggregate stability index and mean weight diameter of soil particles, for various amount of soil conditioners also showed that using these materials with improving soil physical properties, decreasing surface sealing, and enhancing infiltration rate, will reduce soil loss.          

Key words: Soil conditioners, man-made erosion control materials, simulated rainfall, runoff and sediment yield.