Contribution of termites to the breakdown of straw under Sahelian conditions

The effect of termites on the breakdown of Pennisetum pedicellatum straw un der Sahelian conditions was studied in northern Burkina Faso during the dry and wet seasons of 1995. Litterbags were laid on plots treated with drield rin at a rate of 500 g a.i. (active ingredient) ha(-1) to exclude termite a ctivity and on untreated plots. Termites were the only macroscopically visi ble consumers which were observed in the litterbags during the dry and wet season. In lilterbags with no termites present the rate of breakdown of str aw was lower during both the dry or wet seasons than in litterbags with ter mites. 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 D ecember, 28% of the straw disappeared from termite-infested litterbags vers us 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 experi ments. Under Sahelian conditions, the breakdown of organic residues is stro ngly influenced by termites.