Variation of soil shear strength in Larix gmelinii forests under different fire severities and its effecting factors
[Objective]This study reveals fire-induced changes in soil shear strength and physicochemical properties as well as responses to soil erosion processes so that forest managers can more effectively plan and manage post-fire in areas that are vulnerable to fire disturbance.[Method]Selected pure forest floor soils of Greater Khingan Range(Larix gmelinii),a typical forest ecosystem in the Greater Khingan Range forest.The unburned control sites(CK)was used as a control,and after the survey,the forest sites that had experienced low severity burned(L)and the forest sites that had experienced high severity burned(H)were selected as the sites for the two different treatments,shear strength and soil physicochemical properties were determined for each treatment and soil profiles were dug.[Result]1)One-way analysis showed that soil cohesion significantly increased by 17.32%and angle of internal friction significantly increased by 29.28%in the high severity burned sites compared to the unburned control sites,and there was no significant change in the low severity burned sites compared to the unburned control sites;2)Mantel analysis showed that soil bulk weight,pore space,water content,and organic matter were the main factors affecting the shear strength of both low and high severity burned soils;3)different contributions of soil physicochemical properties to the effects of soil cohesion and internal friction angle under different burned severities.Soil cohesion in unburned control sites:SWC(P＜0.05)＞SOM(P＜0.05)＞BD＞SP;Soil internal friction angle of unburned control sites:SWC(P＜0.001)＞BD(P＜0.05)＞SOM＞SP;Soil cohesion in low severity burned sites:SP(P＜0.001)＞BD(P＜0.001)＞SWC＞SOM;Soil internal friction angle of low severity burned sites:BD(P＜0.001)＞SWC(P＜0.05)＞SOM＞SP;Soil cohesion in high severity burned sites:SWC(P＜0.001)＞SP＞SOM＞BD;Soil internal friction angle of high severity burned sites:BD(P＜0.001)＞SP(P＜0.001)＞SWC＞SOM.[Conclusion]The highly burned sites have experienced more severe soil erosion and have indirectly led to changes in the distribution of soil layers.No serious soil erosion has occurred in the low severity burned sites,and there have been no significant changes in the distribution of soil layers.
万方数据
维普
