Preliminary assessment of the soil impact of charcoal production in Rivers State, Nigeria
The charcoal business is rapidly spreading in Nigeria without adequate knowledge of the soil impact. This study examined the impact of charcoal production on selected soil physico-chemical properties and the spatial extent of such impacts. Soil samples were collected at the core of charcoal production sites and at 5m and 10m intervals from the core in North, South, East and West directions, before and after charcoal production. Soil samples were analyzed for particle size distribution, pH, Ca, K, Na, Mg, total N, available P, organic C, Mn, Fe, Cu, Zn, and Bo, using standard analytical laboratory procedures. Student t-test was used to test for significant differences in soil properties before and after charcoal production at different locations. Change index (%) was computed for different locations to ascertain the extent of change in soil properties following charcoal production. There were no significant differences (p > 0.5) in percentage sand, silt and clay before and after charcoal production at the core and both 5m and 10m distances in the four directions. Mn, Fe, Cu, Zn, B, pH, exchangeable cations and percentage base saturation increased after charcoal production and varied significantly (p < 0.5) before and after production especially at the core. Organic C, total N and available P increased by 0.82%, 0.15% and 13.10mg/kg respectively at the core after charcoal production. Indices of change for soil properties were highest at the core and decreased with increasing distance from the core. The study showed that charcoal production increases the level of most soil chemical properties and that such increase diminish with an increasing distance from the centre of the production site. However, longer period of sampling at specific time intervals is recommended to ascertain the longevity or otherwise of such impacts.
Key words: Charcoal, Soil, Change index, Niger Delta, Nigeria