Localisation of Compaction Zones

Since 2015, the National Soil Monitoring Network NABO records soil compaction at selected sites. To do so, the penetration resistance at selected sites is measured with a penetrometer (PANDA sensor) down to a maximal depth of 100 cm. At the same time, core samples are taken to determine water content and bulk density; combined with the pedological description of the core samples, the data give a good picture of the soil compaction state (Figure). It is planned to determine the degree of compaction based on the large-pore volume, air permeability, gas diffusion and shrinkage analyses of cylindrical soil samples.

The driving on soils and the soil cultivation physically impact soils and thus compact their fragile structure. Along with the destruction of soil aggregates, the cavity system with its pores is damaged. Their volume shrinks and their continuity decreases, impeding aeration, infiltration capacity and water retention capacity. As a result, the biological activity in the soil declines. Physical damage below the standard plough depth has especially severe consequences. The compaction of subsoil impacts the functionality of the ecosystem in the long term. Neither natural processes nor technical measures can reverse these adverse effects in a reasonable timeframe.  

Figure: Profiles of core samples taken at two arable sites of the NABO measurement network. Illustration of the measured penetration resistance (n=20), bulk density and gravimetric water content in 5 cm layers of four core samples. Horizons edged in red are considered compacted.