Agricultural practices representing less disturbance, integrated residue management and crop rotation/diversification are expected to result in intermediate turnover rates of soil macro- and micro-aggregates, thereby optimizing the balance between their protective (C sequestration) versus productive (N availability) functions (reference). Field microplot studies that involve the application of ¹⁵N labeled residues of different qualities enable us to directly link aggregate turnover and associated C and N dynamics. These microplots are established in fields with and without exclusion of soil macrofauna, to be able to determine the role of soil macrofauna in aggregate and C turnover and N availability. Integration and upscaling of the results from the three complementary projects is achieved through the calibration and validation of the hydrological and mineralization modules of crop growth and SOM turnover models based on the data from the three projects. After calibration and validation of the models for savannah systems in West and East Africa, these models can be used for scenario studies on optimum management (organic +/- mineral inputs, tillage and rotations) of cropping systems under specific climate and soil conditions and the development of a decision support tool for optimum management of resources for crop production.