Erosividade da chuva em municípios do Mato Grosso: distribuição sazonal e correlações com dados pluviométricos

The rainfall erosivity constitutes an indispensable factor for prediction of soil losses by water erosion. In this way, the present study was carried out with the objectives to model the relationship among the erosivity index (EI30) monthly values, obtained from rainfall chart data with the precipitation and monthly rainfall coefficient for four municipal districts (Canarana, Sao Jose of Rio Claro, Poxoreo and Vera) of Mato Grosso State; to determine the erosivity factor (R) obtained from rainfall data for the four municipalities, as well as its return period and its occurrence probability; and to study the EI30 annual, seasonal and monthly distribution in these four municipalities. The potential relationship between the rainfall erosivity index and the rainfall coefficient make possible to evaluate the monthly and annual rainfall erosivity with good reliability (ERM < 7%) for the municipalities of Canarana, Vera and Sao Jose of Rio Claro. However, for Poxoreo this good reliability is verified only for the annual erosivity. In the four municipalities the spring and summer seasons correspond to the period of larger erosivity, being responsible, except for Poxoreo, for 94% or more of the annual total erosivity.