Evaluation of soil physical and hydrological properties in burned grasslands in Durango, Mexico.

The soils of the state of Durango are diverse and support a wide variety of vegetation types and land uses of significant ecological, social, and economic importance. Grasslands, in particular, are fragile forest ecosystems in the face of wildfires, since fire greatly affects soil properties such as bulk density, porosity, mechanical resistance to penetration, infiltration, and soil permeability. This research aimed to evaluate the effects of fire on the physical and hydrological characteristics of soils in grasslands in the El Salto region of Durango, Mexico. Two plots were identified and established: a) a plot burned in January 2025, with a total impact on grassland biomass; b) a control plot adjacent to the fire, which was not impacted by the fire and presents a characteristic grassland cover. According to the results, the variables showed significant differences between the plots evaluated, except for basic and accumulated infiltration. Specifically, initial infiltration decreased by 65% compared to the control area, while humidity decreased by more than 30%. Baseline infiltration ranged from 32 to 56 mm h⁻¹ between the burned and control areas. After the fires, cumulative infiltration decreased by 38%. After the forest fire, the bulk density increased by 16% compared to the control plot (1.05 g cm-3). On the other hand, total porosity behaved inversely to the soil's bulk density. The mechanical resistance to penetration of the burned plot showed a decrease of 25.3%, and the permeability showed the same trend where it was significantly reduced (<55%) with respect to the control plot.