Techniques for the recovery of compacted soils in Europe

Soil compaction due to agricultural vehicle traffic is recognized as one of the major threats to soil productivity, and soil ecological and hydrological functioning. The size and weight of agricultural machinery have significantly increased during the last decades which is likely to have increased compaction levels. The recently published report of the mission board for soil health and food, “Caring for soil is caring for life” (European Commission, 2020) estimates that the area of land failing soil health due to compaction is 23-33% (7% of which outside agricultural area). Preventing soil compaction is important because the effects of structural decay can affect yields for decades and the decreased infiltration and storage capacity. Once a soil becomes compacted, there are several techniques to solve this. However, the question is which techniques are available, how long they are effective and under what conditions they are best used. In this research, which is part of the EJP SOIL SOILCOMPAC project, an extensive literature review was conducted and combined with data from current recovery field experiments. An overview is made of past and running experiments on recovery methods in different countries to characterize the rate of recovery by different processes and the relative importance of the recovery mechanisms across pedo-climatic zones. The review includes mechanical (tillage), biological (“biosubsoiling”) and natural (soil physical processes) methods. The research was made on the compacted subsoil below the plough layer (25-50 cm b.s.). This means that the focus is on arable farming however most of the recovery techniques can also be applied to grassland.