Role of fire on soil organic matter turnover and microbial activity in a mediterranean burned area

Publisher Summary This chapter examines the effects of light, intense experimental fires, and of wildfire on the soil microbial biomass and activity and on organic carbon turnover in a coastal area of southern Italy. In the study discussed in the chapter, wildfire that mainly affected plant cover caused a rise in the input of organic matter to the soil but did not significantly influence total microbial biomass or fungal mycelia. In contrast, experimental fires developing on the soil surface caused a decrease in the organic carbon and in total microbial biomass and fungal mycelia. All types of fires resulted in an increased soil potential respiration and metabolic quotient. Moreover, increase in the coefficient of endogenous mineralization after experimental fires and increase in the soil CO 2 emission after wildfire were also observed. The data suggest that burned soils may be an important source of carbon for the atmosphere for several months after fire occurrence. In the case of wildfire, the increase of CO 2 emissions from burned soils depends mainly on the increase in soil microbial activity because of the increase in organic matter in the soil and to some degree on stress conditions. In the case of experimental fires, the increase of CO 2 emissions is because of stress conditions.