Abstract

PANDO MORENO, Marisela et al. A comparison of methods in estimating soil water erosion. Invest. Geog [online]. 2003, n.51, pp.23-36. ISSN 2448-7279.

A comparison between direct field measurements and predictions of soil water erosion using two variant; (FAO and R/2 index) of the Revised Universal Soil Loss Equation (RUSLE) was carried out in a microcatchment o 22.32 km² in Northeastern Mexico. Direct field measurements were based on a geomorphologic classification of the area; while environmental units were defined for applying the equation. Environmental units were later grouped within geomorphologic units to compare results. For the basin as a whole, erosion rates from FAO index were statisticall; equal to those measured on the field, while values obtained from the R/2 index were statistically different from the res and overestimated erosion. However, when comparing among geomorphologic units, erosion appeared overestimated in steep units and underestimated in more flat areas. The most remarkable differences on erosion rates, between the direct and FAO methods, were for those units where gullies have developed. In these cases, erosion was underestimated by FAO index. Hence, it is suggested that a weighted factor for presence of gullies should be developed and included in RUSLE equation.

Keywords : Erosion; soil; RUSLE; microcatchment; Mexico.