Effects of charcoal production on soil biodiversity and soil physical and chemical properties in Togo, West Africa

Abstract

In Togo, traditional energy sources including charcoal represent 80% out of total household energy requirements. The techniques of charcoal production in earth kiln are quite common. During carbonization, the temperature rises from 20 to over 500°C. This study focuses on the impact of this high temperature on the soil properties and soil fauna in three biogeographical zones of Togo. The methodology used consists in comparison of soil sampling in surface layer (0-20 cm depth) inside burnt plot i.e. inside the kiln to an unburnt plot in charcoal production area. The results revealed that the soil physical, chemical and microbial properties were altered. The organic matter was destroyed; it is higher at the unburnt plot level than inside the kiln. The soil pH increased at the kiln level by the provision of rich ash bases during the carbonization. Fire increased the permeability at the kiln level by raising the bulk density and the total porosity of soil. The variation in microbial biomass induced by the heat around the kilns is different according to the ecosystem; it is of 15 m radius around the kilns in Sudanian or Guinean savanna areas while this radius is 5 m in Semi-deciduous forest. The soil fauna assessment permitted to record 81 micro-organisms belonging essentially to the Beetles, Hymenoptera, Heteroptera, Diptera, Orthoptera, Myriapods, Homoptera, Acarians, Nematodes, Isoptera, etc. The hypogeal biodiversity index calculation (average species richness, Shannon average indexes and average evenness) revealed that farther moving away from the kiln, greater the fauna species diversity was.

© 2009 International Formulae Group. All rights reserved.

Key words: Charcoal production, kiln, soil physical and chemical properties, soil biodiversity, Togo.