Desenvolvimento e verificação de métodos indiretos para a estimativa da Erodibilidade dos Solos da Bacia Experimental do Alto Rio Jardim – DF
Revista Brasileira de Geomorfologia
Palavras-chave: erosão, perda de solos, fator K, EUPS, bacia experimental. Abstract The difficulty in directly determining the soil erodibility (K-factor) stimulates the development of indirect methods to estimate it from other soil characteristics easier to determine. However, so far, there is not a universal indirect method that can be applied for estimating dependable soil erodibility values. The objective of this paper was to define the best way for estimating the Kfactor of the soils from
... of the soils from the upper Jardim experimental river basin, located in the Federal District of Brazil. Four methods were evaluated and the results discussed and compared to measured data. The paired t-Student test at a significance level of 0.05 was used to compare the averages K-values calculated from each tested method and none of them was found to be statistically equivalent to the measured values. The methods of Denardin (1990) , van der Knijff et al. (1999), and Stone & Hillborn (2002) overestimated the measured values, while the nomograph of Wischmeier et al. (1971) underestimated them. In spite of being a common practice, the assignment of an average erodibility value to represent each soil class demonstrated to be an important source of errors and, because of that, it should not be recommended. Among the tested methods, the Denardin's method was the one which gave better approximation to the measured K-values. Thus, considering the Denardin's method and the results of its application, using soil data from the studied basin, a new method was developed for estimating the erodibility value, based solely on the clay percentage from the soil samples. This new method was applied to the upper Jardim experimental river basin in a spatially interpolated form and the obtained results were considered better than the ones generated by using a unique erodibility value for each soil class.