An Approach for Describing the Effects of Grazing on Soil Quality in Life-Cycle Assessment

Describing the impact of farming on soil quality is challenging, because the model should consider changes in the physical, chemical, and biological status of soils. Physical damage to soils through heavy traffic was already analyzed in several life-cycle assessment studies. However, impacts on soil structure from grazing animals were largely ignored, and physically based model approaches to describe these impacts are very rare. In this study, we developed a new modeling approach that is closely related to the stress propagation method generally applied for analyzing compaction caused by off-road vehicles. We tested our new approach for plausibility using a comprehensive multi-year dataset containing detailed information on pasture management of several hundred Swiss dairy farms. Preliminary results showed that the new approach provides plausible outcomes for the two physical soil indicators macropore volume and aggregate stability.