Combined Effects of Compost, Supraxone and Lambda-Super on Soil Microbial Activity under Pluvial Cultivation of Sesame (Sesamum indicum L.) in Burkina Faso

Abstract

Sesame cultivation is strategic for the economy of Burkina Faso. Indeed, after cotton, sesame is the second most important agricultural product for exportation. However, its production is limited by plant diseases and pest attacks. Facing this situation, large amounts of pesticides are used to boost productivity. But, these chemicals have a negative impact on soil fertility. In this instance, the effects of Supraxone and Lambda-super in the presence of compost on soil microbial activity under rainfed sesame cultivation in a peasant environment were studied. The experiment design was a block of Fisher (BCR) comparing the non-treated parcel (TNT) to the parcel amended only with compost (C) and to the parcel amended with compost and treated with the pesticides (C + P), respectively. Soil samples were taken at depths of 0 -20 cm before sowing at 41st and 81st days after sowing. Respiratory activity and soil microbial biomass were monitored respectively by respirometric tests and by the fumigation-incubation method. The results show that the addition of compost into the soil with or without supraxone treatment and Lambda-super resulted in an increase in microbial biomass and soil respiratory quotient. These results show that the provision of compost in sufficient quantity corrects the inhibitory effect of soil biological activity by pesticides.