An Assessment of Water and Soil Losses in Pastures of The Brazilian Savanna Using Simulated Rainfall

Abstract

Pastures occupy a large part of Brazilian national territory, being of heterogeneous characteristics and varying in climate, fertility, and management. Water erosion, generated by the action of rainfall, is a principal source of soil depletion. These soils exhibit distinct behaviors spatially and temporally. Therefore, this research aims to evaluate the water and soil losses in a pasture of the Cerrado region during two periods of the year (winter and summer) with the aim of understanding the hydro-geomorphological dynamic of the pastures in question. A rainfall simulator was calibrated at 64.34 mm/h, to replicate similar intensities to those of the study region, for 30 minutes (32.17 mm) over four erosion plots. Overall, the plots presented low water and sediment losses, with the largest runoff volumes in the summer and the highest erosion rates in winter. These results are connected to seasonal climate variations expressed in the region, which are reflected in the plant growth habits, generating alterations in the structural quality of the pastures. It follows that the return of the rainy season (winter-summer transition) represents a critical phase for the triggering of the erosive process.