Impact of biomass burning activities on physicochemical properties of nitisol in Southwestern Ethiopia

Burning of biomass for charcoal production and land preparation is common in Ethiopia. However, the analysis of the impacts of these practices on soil physical and chemical properties is seldom examined. Therefore to investigate the impact of biomass burning on selected soil properties, composite and core soil samples were collected at a depth of 0–20cm from cultivated land, a charcoal production site, and farmlands where crop residues are burned for land preparation. The study showed while burning of biomass significantly (P<0.01) decreased bulk density and clay percentage while the sand fraction was increased significantly (P<0.01). However, the differences in silt percentage and water holding capacity were non-significant (P>0.05). Burning also increased pH, electrical conductivity, available phosphorous, CEC (cation exchange capacity), and exchangeable bases significantly (P<0.01) as compared to those in cultivated land. Furthermore, charcoal production significantly (P<0.01) increased organic carbon and total nitrogen, but burning of crop residues for land preparation reduced them significantly (P<0.01). The formation of ash and charred biomass due to burning might improve most soil properties. But this causes environmental pollution and therefore it is useful to study the long term impact of biomass burning on soil properties. Moreover, it is important to consider a biochar strategy in order to mitigate global warming and enhance soil productivity.