In this project we will investigate for a number of different forms of conservation tillage with different management of organic matter, how the soil microbial biomass and the soil fauna (nematodes, collembola and mites) influence the nitrogen mineralisation immobilization turnover. To this end, incubations will be done with different inocula of soil microbial biomass and soil fauna. Furthermore, the influence of soil structure on these dynamics will be studied using X-ray nano CT scans.