Soil heterogeneity and how it controls ecosystem functions and soil development

Soil structure is complex and dynamic on various scales. Soil heterogeneity as an expression of soil structural complexity develops over time and is controlled by biological, physical and geochemical processes and their interactions. Biotic and abiotic mechanisms shape the soil (micro)environment by forming interconnected pore spaces and solid particle arrangements. Commonly soil development begins with a more or less homogeneous initial structure which evolves towards an increasingly heterogeneously shaped soil architecture serving as a habitat of living organisms and in turn controlling matter, energy and gas fluxes. The relationship between soil structure and function seems to result in a self-organized system of pores and biogeochemical interfaces that is in equilibrium with its boundary conditions. 

In this presentation, we will demonstrate the interaction between soil heterogeneity and function using imaging approaches. Examples will include (i) root – soil interactions and rhizosphere oxygen distribution, (ii) spatial distribution and mineralization of organic matter in soil aggregates with contrasting architecture, (iii) the effect of initial soil heterogeneity on soil structural evolution and (iv) in-situ deformation patterns upon mechanical stresses. These examples provide an insight into the internal dynamics of soil architectures and their related physical, biological and geochemical processes which are important to understand ecosystem-relevant soil functions.