Contribution of termites to the breakdown of straw under Sahelian conditions

Abstract

 The effect of termites on the breakdown of Pennisetum pedicellatum straw under Sahelian conditions was studied in northern Burkina Faso during the dry and wet seasons of 1995. Litterbags were laid on plots treated with drieldrin at a rate of 500 g a.i. (active ingredient) ha^–1 to exclude termite activity and on untreated plots. Termites were the only macroscopically visible consumers which were observed in the litterbags during the dry and wet season. In litterbags with no termites present the rate of breakdown of straw was lower during both the dry or wet seasons than in litterbags with termites. In the litterbags with termites, much of the mulch was taken off and replaced by termite-made sheeting. From April to September over 60% of the added material disappeared from termite litterbags, while only 18% of the added straw disappeared from litterbags without termites. From October to December, 28% of the straw disappeared from termite-infested litterbags versus 8% from litterbags without termites. The contribution of termites to the breakdown of straw was estimated to be over 70% for each of the two experiments. Under Sahelian conditions, the breakdown of organic residues is strongly influenced by termites.