Soil biota play a fundamental role in a number of soil services like food and fibre production, carbon sequestration and nutrient cycling. Due to increased intensive land use, soil biodiversity is threatened, which has consequences for these services. The microbial pathway in soil food webs is responsible for the major flow of energy and matter in soil food webs. The biodiversity-ecosystem functioning relationship of this microbial pathway is, however, poorly understood. In this project we use new experimental molecular techniques to trace the microbial decomposition of different organic substrates. The experimental data that will come out of this experiment will be used to improve soil food web models, which will increase our understanding of the effects of land use on soil functioning, which can contribute to sustainable land use.