Collaboratrices et collaborateurs

Soil structure plays a crucial role in determining functional soil properties essential for crop growth, including water infiltration, water retention, and mechanical resistance, which directly impact water availability to crops and accessibility of resources by roots. Soil management affects soil structure directly through loosening by tillage and traffic compaction, as well as indirectly, for example by influencing soil organic carbon (SOC) content, earthworm abundance and activity, and root growth. In the SoilX project, we evaluated how soil hydraulic and mechanical properties respond to differences in soil management. Our assessments encompassed measurements of saturated and unsaturated hydraulic conductivity, water retention, aggregate stability, and penetration resistance in the topsoil and in subsoil layers. In addition, we measured earthworm abundance and visually assessed the soil structural quality. Basic soil properties including texture and SOC were also measured. We sampled over 100 experimental plots across ten long-term field experiments (LTEs) in Europe. To compare soil management across LTEs, we calculated numerical soil management indicators. Preliminary data analysis of the Swiss LTEs revealed that tillage intensity had a negative and soil cover a positive impact on earthworm biomass, and that saturated hydraulic conductivity was positively correlated with earthworm biomass. Higher carbon inputs were associated with increased SOC contents, higher unsaturated hydraulic conductivity, and slightly larger amounts of plant-available water. Comprehensive analyses of data from all ten LTEs are currently on-going. The preliminary findings underscore the significant impact of soil management on soil structure and function. Quantitative relationships between soil management and soil structural properties derived in the SoilX project will help guide the development of sustainable soil management strategies aimed at enhancing soil health and resilience to climatic extremes.