Direct and indirect erodibility indexes for two latosols from lavras minas gerais state brazil
Ciencia e Pratica 15(2): 186-193
The erodibility index factor (k) from Universal Soil Loss Equation was determined for two very clayey Oxisols (Dark Red Latosol and Red Yellow Latosol with 64% and 7.3% slope, respectively). K values were evaluated by direct method (kd) through a rainfall simulator and by indirect method through the nomograph of the Wischmeier et alii in its original (k1) as well as modified proposition (k2). The Red Yellow Latosol showed to be more susceptible to erosion (kd = 0.13; k1 = 0.19; k2 = 0.23) than the Dark Red Latosol (kd = 0.05; k1 = 0.14; k2 = 0.18). The direct method resulted in an index three times greater for the Red Yellow Latosol than for the Dark Red Latosol, whereas for the indirect method such a difference was only about 32%, also in favour of the Red Yellow Latosol. Silt plus fine sand content, permeability plus solum depth and the type of method (direct and indirect) were the most probable factors affecting k values.