Soil structure – a dynamic soil property which effects multiple soil functions

Soil structure is a dynamic property of soils, which refers to temporal changes in the spatial arrangement of pores, organic matter, and minerals. As for many chemical reactions, also soil structure can be at a state of dynamic equilibrium, in which bulk properties, such as macroporosity, average pore size, and others apparently remain constant even though pores are formed and destroyed continuously. On the long term, the creation and destruction of structural properties are in balance as long environmental conditions, such as climate or cover crops, do not change or no external disturbances, such as tillage, become effective.

The irreversible redistribution of soil constituents, i.e. soil structure turnover, itself determines essential soil functions. For example, the creation and disruption of a pore network affects water flow, water storage, and aeration. Microsites of higher densities limit the accessibility of plant residues and organic amendments for microbiology through pores, and in consequence, increase the capacity of soil to store organic carbon. However, so far there are only few experiments trying to capture these dynamic processes and quantify the contribution of different drivers. Using examples describing the relationship between soil structure and soil functions at different sites, I will show that there is a need for new long-term monitoring experiments to capture these dynamics at temporal resolution.