Stimulation of soil macrofaunal biodiversity by the judicious use of organic resources, crop rotation and soil cultivation is expected increase water and nitrogen use efficiency. Soil samples taken during the survey (see PhD project 1: (summary) are analyzed for aggregate stability and -size distribution. Combined with soil macrofauna data from project 1 this provides information on the interrelations between management, soil macrofauna and structural characteristics of surface soils. 5 long-term trials (3 in Burkina Faso and 2 in Kenya) are selected for in-depth study of how changes in physical and hydrological soil properties, induced by differences in management and related macrofaunal biodiversity, determine the water and nitrogen use efficiency by the crop. We hypothesize that increased aggregate stability, porosity, infiltration rate and water retention capacity lower evaporation, percolation and runoff losses, thereby increasing plant-available water. We combine data on plant water use with crop-N data to relate soil management-induced changes in the partitioning of the rainfall over soil evaporation, plant transpiration, runoff and deep percolation to nitrogen use efficiency (NUE) and water use efficiency (WUE).