Erodibility of a Lithic Ustorthents by the modified Inderbitzen test and efficiency of soil-cement blocks to control water erosion

ABSTRACT

Soil erosion is the main cause of soil degradation throughout the world. From a geotechnic perspective, soil erodibility is important for assessing slope stability, commonly being determined in laboratory tests. The aim of this study was to estimate the erodibility of a sandy Lithic Ustorthents using a modified Inderbitzen test, as well as to evaluate the effect of buffer blocks in reducing soil losses by water erosion. The modified Inderbitzen tests were performed on undisturbed soil samples, collected within metallic frames measuring 0,4 x 0,2, 0,15 m. These samples were subjected to simultaneous applications of water in the form of simulated rain (300 mm.h^-1) and surface runoff (6 L.min^-1). The effects of soil cover (absent x present), slope (5%, 17,5% e 35%), buffer blocks and their spacing (0,1 m, 0,2 m e 0,4 m) were evaluated in a completely randomized design. Average soil losses for the Lithic Ustorthents ranged from 0,03 to 2,1 g.cm^-2 and the estimated erodibility was 0,0034 g.cm^-2.min^-1.Pa^-1. Soil cover and slope were the most important experimental factors affecting soil loss. The buffer blocks significantly reduced soil losses only when soil cover was present and in the highest slope tests (35%). In the tests without soil cover, the buffer blocks resulted in non-significant differences.

Keywords:
rill erosion; erosometer; hydraulic shear stress