Soil biodiversity is essential for sustainable crop productivity in agroecosystems by performing
various functions which regulate soil processes and nutrient cycling. Termites and earthworms
are the main group of invertebrates in the Sahel West Africa having significant effects on
ecosystem services. The objective was to determine whether the biogenic structures produced by
termites and earthworms shift enzymes activities, microbial diversity and nutrient cycling during
decomposition of Piliostigma reticulatum residue. The experiment was a randomized block
design conducted at two sites which have been amended with stems and leaves of Piliostigma
reticulatum (2,3 Mg ha-1). Within 21 days after amending residues to the soil, samples were
taken from fresh biogenic structures of termites (Nasutitermes torquatus) and earthworms
(Millsonia inermis) and a control soil (0-10 cm depth). Samples were analyzed for C, N,
extractable P Bray, enzymes activities (β-glucosidase, N-Acetyl-β-glucosaminidase, acid phosphatase) and microbial community structure. The results showed that the β-glucosidase and N-Acetyl-β-glucosaminidase activities from biogenic structures as well as their nutrient contents were significantly higher than the control soil. Interestingly, there were no significant differences of these enzyme activities between the termite and earthworm biogenic structures.
Conversely, acid phosphatase activity was higher in earthworm structures than those of termites or the control. The termite and earthworm structures had larger total microbial biomass, bacteria, and fungi communities than the control. Earthworm biogenic structures exhibited larger microbial communities than those of termites.

Biogenic structure, Earthworm cast, Microbial composition, Termite sheeting, Soil biodiversity