As an introduction to the XIII ICSZ "Biodiversity of soil organisms and ecosystem functioning" the question is raised what contribution soil ecology has made to general ecology. Although the appearance of soil ecological papers in general ecological journals is limited, soil ecologists have had a major contribution to especially functional aspects of ecology like nutrient release and energy turnover mechanisms, perhaps partly due to the applied character of soil ecology. As a way forward it is suggested to unify further work and scientific discussions according to five research themes: 1. Combined spatial and temporal heterogeneity; 2. Scaling up from individual mobility via distribution patterns to bio-geography; 3. Structural and functional biodiversity: from gene- to ecosystem level; 4. Nutrient cycling/energy transfer at the micro- to macro-level; 5. Adaptability from bacteria to ecosystems: is there a mutual mechanism connecting genetic variation with ecosystem adaptive mechanisms?