Hydropedology at the Mantiqueira Range, Southeastern Brazil

Abstract

One of the greatest challenges facing society in the coming years will be to use natural resources in a sustainable manner. In the Southeast of Brazil, the Atlantic Forest is disappearing at an elevated rate. Currently only 7% of the original area exists as mostly fragmented remnants distributed over areas difficult to access, such as Mantiqueira Range. In these areas, the predominant soils are Inceptisols, which constitute very fragile soil systems. Land-use changing combined with shallow Inceptisols lead to important impacts on hydrology. Therefore, studies that address streamflow behavior in these landscapes are urgently needed for understanding the groundwater recharge process. In headwater watersheds, knowledge about spatial distribution of soilwater transmissivity can be important to support the sustainable use and conservation of the environmental resources. This study aimed: to characterize a mountainous Inceptisol under a highland tropical climate in Southeastern Brazil, taking into consideration the soil physical, chemical and micromorphological analyses, under native forest and extensive pasture; to investigate the role of shallow Inceptisols linked to the land use changes in the streamflow behavior at Mantiqueira Range region, and to understand the mechanisms of water flow into the saturated zone; and to evaluate the application of pattern recognition on landscape classification tools combined with digital soil mapping techniques for soil-water transmissivity mapping in a watershed located at the most important Brazilian headwaters, in Southeastern Brazil. Micromorphological analysis suggested an intermediate stage of mineral weathering and soil development, which is in accordance with properties expected to be found in Inceptisols. Water balance for two years (2009-2011) showed that the flow stored in the saturated zone in Inceptisols under forest occurs rapidly, increasing its potential for storage, characterized by the process of refilling water. Areas with native forest play a fundamental role in water distribution processes in the soil profile in mountainous catchments in Southeastern Brazil. These results strengthen the importance of soil conservation practices and adequate land-use to maintain the water yield in this environment in Brazil.