Water repellency in neotropical savannas: what do we really know?
The Cerrado (Brazilian savanna) is the second-largest Brazilian biome and has several phytophysiognomies – grassland, savanna, and forest formations – which have a high diversity of plants and animals, making it one of the global biodiversity hotspots. In addition, the biome contributes significantly to several Brazilian watersheds. However, knowledge about the components of the water balance within the Cerrado remains incipient. Studies show that some factors influence the entry of water into soils, such as changes in its use, types of management, plant density, physical properties of the soil, and water repellency. The latter is observed in different types of soil in different biomes and is often associated with the quality of organic matter and soil moisture content, and can be exacerbated by fires, common during the dry season in the Cerrado. In general, the increased water repellence of soils makes infiltration difficult, impacting various components of the ecosystem. Despite its importance, the phenomenon of water repellency is poorly known in natural areas of the Cerrado. Therefore, the objective of the present project is to monitor the phenomenon of water repellency in two areas covered by Cerrado Típico, over six months. It is expected that the degree of water repellence of the soils will be greater during the beginning of the dry season and that with the increase in rainfall it will gradually decrease. Thus, the project seeks to answer the following questions: Is there water repellency in the Brazilian Neotropical savanna? If so, is this a seasonal phenomenon? Is soil water infiltration influenced by it? The mini-disk infiltrometer (for water infiltration in soils) and the WDPT test (Water Drop Penetration Time) to assess the degree of water repellence of the soils will be tested in the field. Finally, samples of the soil will be collected to assess their texture and organic matter content.