Variation de l'activité biologique dans les zipella (sols nus) en zone subsahélienne du Burkina Faso et impact de la technique du zaï (techniques des poquets)

Abstract

Changes in the biological activity of zipella (bare soils) in the subsahelian zone of Burkina Faso and impact of the technique of zaï. The study focused on the two types of bare soils (zipella) located in the north-center of Burkina Faso: a lixivied ferruginous soil and an eutrophic brown soil. The biologic activity was evaluated in relation to soil surface characteristics and soil depth.The impact of the «zaï» technique processing on the biological activity was also investigated. The physico-chemical characteristics of the ferruginous soils were globally lower than those of the brown soils. For the same type of soil these characteristics were lower in the bare surfaces compared to ones of surface covered by vegetal. The global microbial biomass was lower in the bare soils compared to the one of the soil covered by vegetal. The microbial biomass of the ferruginous soils was lower than the brown soils one. Irrespective of the soil surface characteristics and the type of soil surface, the biological activity was more important in the soil surface layer than in the deep soil. The processings of zaï technique improved notably the biological activity in the brown soils.

Keywords

• Biological activity
• zipella (bare soils)
• Azospirillium
• technique of zaï
• brown soil
• ferruginous soil