Modifications induced in soil physicochemical properties by repeated fire for different fuel load treatment in a West African savanna-woodland

Abstract

Fire is known to stimulate growth of savanna vegetation, promote species’ diversity, and regulate tree and grass balance. However, the timing and frequency at which savannas are burned and the fuel properties can affect residual soil nutrient content and, ultimately, productivity. The objective of this study is to characterize changes in soil physical and chemical properties in a savanna-woodland subject to different fuel load treatments of burning. To characterize the soil physical and chemical variables, particle size distribution, total carbon, pH, phosphorous content and nitrogen were analyzed for three different soil layers. The results indicated no difference in soil texture between the different topsoil profiles before and after the burning event. Further, there was greater nutrient enrichment of the upper soil layer (p=0.014) due to ash deposition. The spatial patterns of soil temperature during the studied experimental fires could affect soil properties, resulting in new spatial pattern of soil nutrients. The findings of the present study have practical implications for savanna management. The current implementation of prescribed early fires should be continued with due consideration of the burning and fuel properties to avoid detrimental effects of intense fire on soil layers. Key words: Early fire, fire behavior, fire temperature, soil properties, Savanna ecosystem.