Índice de qualidade do solo associado à recarga de água subterrânea (IQSRA) na Bacia Hidrográfica do Alto Rio Grande, MG

Abstract

In the last years, soil quality indexes for analyses of the environmental sustainability and agricultural production have been proposed in increasing numbers. However, none of these indexes is related to the groundwater recharge soil quality index for conditions in Brazil. The objective of this study was to generate a soil quality index related to the groundwater recharge (SQIGR) of the physiographical conditions of the Upper Rio Grande Basin and to draw a map of SQIGR using geostatistical procedures. The proposed SQIGR consists of a linear combination of three properties related to water infiltration into the soil: bulk density, saturated hydraulic conductivity and macroporosity. To validate the index, the participation of the base flow in the total flow of four sub-basins of the Upper Rio Grande Basin was considered, analyzing the behavior of this hydrologic indicator taking the spatial distribution of SQIGR as reference. This validation process indicated the importance of SQIRG as tool to evaluate the groundwater recharge potential since it reflects the influence of different land uses on the base flow behavior and, consequently, on water yield from sub-basins.