Impacts of early and repeated fires on microbial activities in the wooded savannahs of Burkina Faso

Bush fires which effects depend on their intensity as well as their season of occurrence are considered as a major disturbance of savanna ecosystems. The objectives of this research were to understand the changes induced on the properties of the soil by repeated early fires on microbial activities. The study was conducted on a factorial design installed on two (02) sites, namely the classified forest of Dindéresso located in the West (firsts fires were applied in 2010) and that of Tiogo located in the Center West (first fire were applied since 1992) of the country. Measurements have been carried out before, after the passage of the fire and during the rainy season on soils. The results obtained showed that the period during which the measurements were taken played a role in the microbial dynamics, thus showing the highest rates in the rainy season for the control (3.02 C g.m-2) and the burnt plots (3.63 C g.m-2) after fire. Microbial nitrogen is the element that varied considerably, going from 1.60 for the control to 1.74 N g.m-2 for the burnt plots for the Dindéresso site. Concerning Tiogo, the microbial biomass is higher on the burned plots (6.04 C g.m-2) and (6.01 C g.m-2) for the control in rainy season sampling.