Physicochemical properties of soils at different stages of post-fire evolution in northeast Portugal

Fires are common problems in many countries, as in Portugal. These are countries that are under favorable climatic conditions for the outbreak and rapid progression of forest fires. These are one of the main factors of land degradation, causing various changes in soil, water and vegetation. Therefore, forest fires generate great environmental impacts on the landscape where they develop and spread. As the burning occurs, the vegetation cover and organic layer are depleted, and the mineral soil is heated, resulting in changes in the physical, chemical, mineralogical and biological properties of the soil. This study aimed to evaluate soil changes under the impact of fire over time, comparing burned and non-burned areas in the Northeast of Portugal. For this, physical and chemical properties of the soil were studied. The study areas are located in three distinct areas: Parishes of Soutelo, Parâmio and Quintela de Lampaças, respectively burned in 2015, 2016 and 2017. In each study area, sampling areas were chosen in places that burned and did not burn, with the exception of Quintela de Lampaças. Samples were taken randomly at 4 sampling points. Laboratory analyzes of the physical and chemical properties of the soils were carried out to assess the changes in the soil as a result of fires and post-fire recovery. It can be concluded that the physicochemical properties of the soils changed differently along the soil profile and the fire interfered with these properties which over time tend to evolve to the pre-fire situation.