MBONU, O. A. and BABALOLA, O. (2003). Water Infitrability as affected by topsoil Removal. Afri. J. of Agric. Res., vol. 1(1&2):53-56.
Abstract:
Water infiltrability of an alfisol in the semi humid tropics, as affected by different levels of desurfacing, were investigated using the double ring infiltrometer. Both the initial and equilibrium infiltration rates (IR) varied with level of desurfacing. There were no significant differences between the IR of the control and the -2cm depth of desurfacing (<0.05). The initial and equilibrium IR for the -5 and -15cm desurfacing differed significantly from the control. The initial IR was in the order 28 > 10 > 9 > 8 cmhr-1 for -10, -5, 0 and -2cm depths of desurfacing respectively, while the equilibrium IR was in the order was 9.5 > 5.6 > 3.3 > 2.9 cm for -10, -5, 0 and -2 cm depths of desurfacing respectively. The higher infiltration rates of the -5 and -10 depth of desurfacing suggests that the decrease in IR as a result of desurfacing by erosion, as reported by previous works, may not primarily be as a result of surface soil removal but the subsequent crusting sealing of the soil pores with the impact of rain drops. The equilibrium IR highly correlated with physical properties of the soil, with correlation coefficient values (r) ranging from 0.79 to 0.89. The equilibrium IR was multi-regressed with some of the physical properties as follows:
Y = 2.38.85 – 26X1 – 3.8X2 – 0.2X3 + 0.1X4 – 0.08X5, where X1 = % sand, X2 = % silt, X3 = % clay, X4 = saturated hydraulic conductivity and X5 = total porosity.