Seasonal variation in fire temperature and influence on soil CO2 efflux, root biomass, and soil water properties in a Sudanian savanna-woodland, West Africa

Savanna ecosystems are shaped mainly by fires, the consequences of which depend on both their intensities and the season in which they occur. The effects of fire disturbance on key soil parameters are still largely unknown, yet the knowledge of those effects are crucial to our understanding and management of savanna ecosystems. This study was aimed at determining seasonal variations in fire temperature and the influence of fire on soil respiration, root biomass, and soil water infiltration. It was conducted on long-term experimental plots established in 2006 in the savanna-woodland of Burkina Faso. Four fire treatments were applied: no fire, early fire, mid dry-season fire, and late dry-season fire. The results indicated that the average maximum temperature and the residence time of the lethal temperature varied significantly (P < 0.05) depending on the season of fire occurrence, the location of the soil probe, and the interaction between these two factors. The duration of heating above the critical temperature threshold was generally longest at ground level. The season in which fire occurred significantly (P <= 0.001) affected soil respiration, soil root biomass, and soil water infiltration. In conclusion, although fire can be used as a management tool in the savanna, the effects of fire on soil should be considered.