The link between soil biodiversity and soil functioning will be established through the diversity of soil structures, produced by functional groups of earthworms and termites. Such structures are excrements deposited, and burrows made belowground and at the soil surface. In a survey of 13 long-term field trials across the sub-humid – semi-arid agro-ecological zones of West and East Africa we will systematically quantify soil macrofauna biodiversity and relate this to environmental (including soil) variables and drivers. In in-depth studies in 5 of the long-term field trials (3 in Burkina Faso and 2 in Kenya) we quantify how management (organic resource quality and mineral N use, rotation, tillage) affects soil macrofauna diversity and how this is reflected in the diversity of biogenic soil structures, the relative abundance of biogenic and physicogenic structures and the degree of SOM incorporation and association with the mineral soil fraction. We make use of the fact that the morphology of soil structures is inherently related to the activity of specific functional groups, i.e. earthworm and termite groups differing in habitat, food choice, feeding mode and ecophysiology.