Abstract:
Background Forest fires lead to the change of soil properties, seriously damaging forest ecosystems and soil erosion resistance. In order to explore the short-term effects of fire intensity on soil water physical characteristics under different forest stands and soil depths, and to prevent soil erosion and restore forest vegetation in the later stage, it is of great significance to study the changes of soil water physical characteristics in the short term after fire.
Methods In the short term after the fire occurred in Jinyun Mountain, soil samples from three kinds of burning (light, moderate, and severe) areas and 0-10 cmand 10-20 cm soil layers of Pinus massoniana forest and bamboo forest were collected, and soil bulk density and soil porosity were measured by cutting ring method, and soil moisture capacity was measured by oven drying method. Soil infiltration was measured by constant head method.
Results 1) The bulk density of soil in P. massoniana and bamboo forests increased, while the porosity and water holding properties decreased in the short term after burning. 2)The initial infiltration rate, steady infiltration rate, total infiltration rate and saturated hydraulic conductivity of soil decreased with the increase of fire intensity and soil depth. the effects of burning intensity on soil moisture physical characteristics were as follows: severe burning > moderate burning > light burning. The total porosity of soil water was higher in the bamboo forest than in the P. massoniana forest. Bulk density and saturated water capacity: P. massoniana forest> bamboo forest. The soil infiltration rate of different stands showed as follows: bamboo forest >P. massoniana forest.
Conclusions Burning has significant effects on the physical characteristics of soil moisture in different stands, especially in severe burning. The study on the effects of burning on the physical characteristics of soil moisture may provide a theoretical basis for the restoration, reconstruction and management of the ecosystem in burned areas.