Background The effects of fire interfernce on the soil respiration rates of two kinds of woodland in Jinyun Mountain were discussed, and the short-term changes of soil respiration rate and its influencing factors under different fire disturbance levels of different forest stands were clarified, so as to provide a scientific basis for vegetation restoration and soil treatment after fire disturbance in this area.

Methods The UAV survey combined with field inspection was used to divide and deploy fire interference Ⅰ (lightl), Ⅱ (moderate), Ⅲ (severe) and control sample plots according to the blackening height and vegetation damage. The closed dynamic air chamber method was used to measure the soil respiration rate in different areas, and the soil environment and physical and chemical properties were measured at the same time.

Results 1) The change trend of soil temperature in the two forest lands under different levels of fire interference was the same, and the order was: Ⅲ sample plot > Ⅱ sample plot > Ⅰ sample plot > control sample plot. The change trend of soil moisture was opposite to that of soil temperature. 2) The soil respiration rate of mixed coniferous and broad-leaved forest land under Ⅰ, Ⅱ and Ⅲ fire interference was 1.81, 1.5 and 1.38 μmol/(m²·s), respectively, which was 24.9%, 37.8% and 43.8% lower than that of the control. The soil respiration rate of the pure Phyllostachys pubescens forest under grade Ⅰ, Ⅱ and Ⅲ fire disturbance was 2.78, 2.34 and 1.65 μmol/(m²·s), respectively, which decreased by 29.1%, 51.4% and 57.9% compared with the control. 3) Fine root biomass of mixed coniferous and broad-leaved forest and pure P. pubescens forest decreased with the increase of fire grade. Soil pH and C/N ratio increased with the increase of fire interference level.

Conclusions Fire interference increases soil temperature and decreases soil moisture. The soil respiration rate is significantly inhibited with the increase of fire interference level, and there was a significant difference in soil respiration rate under different fire interference levels in the same stand. Under the same fire interference level, the soil respiration rate of mixed coniferous and broad-leaved forests was significantly lower than that of pure P.pubescens forests. There was a significant positive correlation between soil respiration rate and fine root biomass, and a significant negative correlation between soil respiration rate and soil pH, which were the main factors influencing the difference of soil respiration rate under fire interference, development of mixed coniferous and broad-leaved forests may effectively reduce the impact of fire interference.