The study focused primarily on evaluating the ameliorative potential of biocharcoal on sodium azide
toxicity (35 ppm) in African yam bean (
Sphenostylis stenocarpa Hochst. Ex. A. Rich) Harms. A field experiment was
conducted using river sand and mixtures of biocharcoal from
Pentaclethra macrophylla
, represented by 0 (100 % river
sand, control), 25, 50, 75 and 100 % biocharcoal added to ameliorate the toxic effects of sodium azide on African yam
bean. Morphological parameters measured include germination percentage, number of leaves and secondary roots,
percentage seedling emergence, shoot height, number of branches and number of leaves were recorded. The effect of
biocharcoal on the toxicity of sodium azide to soil pH, conductivity, nitrogen, phosphorus, potassium contents and
microbial community were also recorded. The growth of African yam bean was significantly improved by the application
of the biocharcoal as higher plant height, number of leaves, percentage seedling emergence and number of branches were
observed when compared with control. Soil conductivity, potassium and phosphorus were significantly higher in the
treatments with biocharcoal. No positive effect on soil nitrogen content was observed. Biocharcoal addition adversely
affected soil microbial community. Biocharcoal proved to have ameliorative potential however more work is needed to
understand the mechanism by which it operates.
