Rainfall erosive potential in Lavras Minas Gerais State, Brazil: Distribution, occurrence probability and return period

Abstract

Rainfall erosive potential in Lavras, Minas Gerais State, has been studied to improve its land use planning. Rainfall erosivity factor (R), used in the universal soil loss equation, was calculated for a rain gauges series of 15 years. 5403 MJ mm (ha h year)-1 was the calculated value and it is expected to occur at least once every 2.9 years, with a 34% occurrence probability. Maximum individual EI30 values estimated for return periods of 2, 5, 20, 50 and 100 years were 524, 789, 1465, 2206 and 3007 MJ mm (ha h)-1, respectively. Highest soil and water losses are expected from September to March, since 40 % of the annual erosivity index value occurs within that period, when conventional tillage is used for seedbed preparation and the canopy is incipient.