Soil structure, i.e. the spatial arrangement of soil constituents, influences important soil functions such as:
- the transport and storage of water, gases, nutrients and pollutants, and hence their availability to plants and soil organisms; surface runoff and water storage in catchment areas of bodies of water; gas exchange between soil and atmosphere;
- the activity of soil microflora and -fauna, and hence the turnover of organic matter and nutrients, which in turn influences structure formation and reinforcement; and
- soil mechanical properties and hence root growth, as well as soil workability and trafficability.
Unlike soil texture (clay, silt and sand content), soil structure is dynamic, and varies according to mechanical and hydraulic stresses resulting from natural processes (weather conditions, root activity, soil-biological activities) and agricultural activities (compaction by agricultural field traffic, soil tillage) over time periods of seconds to years.
We study the influence of natural processes and agricultural activity (soil tillage, soil compaction from agricultural field traffic) on soil structure, soil conditions for plants and soil organisms (soil water and air balance, state of oxidation), and soil functions (e.g. air permeability, gas diffusion, mechanical properties). Soil compaction caused by agricultural machinery is one of the main focuses of our research. We obtain our new findings primarily from field studies, long-term field trials and laboratory studies, which we combine with theoretical considerations and model simulations.
From our findings, we develop inter alia advisory tools for agriculture, e.g. tools for evaluating the risk of soil compaction. Terranimo® is a free web tool that farmers can use to calculate the compaction risk for their machines in terms of a given operation and given soil conditions. At increased risk, farmers can test various options on how to reduce the risk of soil compaction. Agroscope develops Terranimo® in national and international cooperation.