Impacts of low-intensity prescribed fire on microbial and chemical soil properties in a Quercus frainetto forest

Abstract

Prescribed fire is a common economical and effective forestry practice, and therefore it is important to understand the effects of fire on soil properties for better soil management. We investigated the impacts of low-intensity prescribed fire on the microbial and chemical properties of the top soil in a Hungarian oak (Quercus frainetto Ten.) forest. The research focused on microbial soil parameters (microbial soil respiration (RSM), soil microbial biomass carbon (Cmic) and metabolic quotient (qCO2) and chemical topsoil properties (soil acidity (pH), electrical conductivity (EC), carbon (C), nitrogen (N), C/N ratio and exchangeable cations). Mean annual comparisons show significant differences in four parameters (C/N ratio, soil pH, Cmic and qCO2) while monthly comparisons do not reveal any significant differences. Soil pH increased slightly in the burned plots and had a significantly positive correlation with exchangeable cations Mg, Ca, Mn and K. The mean annual C/N ratio was significantly higher in the burned plots (28.5:1) than in the control plots (27.0:1). The mean annual Cmic (0.6 mg g−1) was significantly lower although qCO2 (2.5 µg CO2–C mg Cmic h−1) was significantly higher, likely resulting from the microbial response to fire-induced environmental stress. Low-intensity prescribed fire caused very short-lived changes. The annual mean values of C/N ratio, pH, Cmic and qCO2 showed significant differences.