Rainfall erosivity in the region of Sete Lagoas, MG, Brazil

Abstract

The objectives of this work were: to determine the rain erosivity of Sete Lagoas, MG; to compare erosivity values determined by two different kinetic energy equations; and to provide equations to estimate the erosivity, through pluviometric parameters. Two hundred and eighty five rain storms were studied (Jan./93 to Dec./95) of which 33% were classified as erosive, corresponding to 73% of the total rainfall amount. The indexes EI₃₀ e KE>25 showed the same behavior throughout the year. The values obtained for the R factor were 5835 MJ mm (ha h year)^-1 and 116.3 MJ (ha year)^-1, for EI₃₀ and KE>25, respectively. The kinetic energy equations utilized provided virtually the same values for the erosivity indexes. The period elapsed between the seeding time and the crop growing season (October to December) is the riskiest time, in regard to soil losses. From March to August, erosivity does not significantly increase.