Seasonal Effects of Wildfires on the Physical and Chemical Properties of Soil in Andean Grassland Ecosystems in Cusco, Peru: Pending Challenges

The soils represent a valuable renewable resource on human timescales and interact with distinctive grassland ecosystems characterized by their elevated biodiversity and essential provision of ecosystem services, such as water supply and carbon sequestration. However, knowledge concerning the effects of wildfires on soil properties and nutrient availability remains limited in the Andes. Andean grasslands currently stand as ecosystems most affected by wildfires in the Peruvian Andes. Our objective is to analyze the effect of fire activity on soil physicochemical properties and analyze its social context in Cusco, situated in the southern Andes of Peru. Five soil samples were collected during both the dry and rainy seasons to characterize changes in soil properties. Additionally, the vegetation restored after the wildfire was analyzed. Changes in soil properties subsequent to the fire indicate slight increases in pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium during the onset of the rainy season; thereafter, a gradual reduction in these values was observed. This reduction can be attributed to the seasonal rainfall and runoff regime contributing to the leaching process. Our findings suggest that the complete regeneration of vegetation following a wildfire may require approximately four to five years. This assertion is supported by the perceptions of the affected population, as revealed through interviews conducted within two local farming communities. These results hold significance for decision-makers in formulating policies and regulations regarding grasslands and their seasonal restoration.