Threats to soil quality in Denmark - A review of existing knowledge in the context of the EU soil thematic strategy
DJF rapport Markbrug, nr. 143, 2009
Af Schjønning, P., Heckrath, G. & Christensen B.T., Dept. of Agroecology and Environment, Faculty of Agricultural Sciences, Aarhus University
The EU Commission is preparing a proposal for a Soil Framework Directive with the purpose of protecting the soil resources in Europe. The proposal identifies six major threats to a sustained quality of soils in Europe. This report addresses the threats that are considered the most relevant under the prevailing soil and climatic conditions in Denmark: compaction, soil organic matter decline, and erosion by water and tillage. For each of these threats, their relevance and geographic distribution for Danish soils and the damages to soil functions are outlined. Next, a procedure is suggested for identifying areas at risk. This exercise involves an explicit identification of: i) the disturbing agent (climate / management) exerting the stresses to soil, and ii) the vulnerability of the soil to those stresses. Risk reduction targets, measures required to reach these targets, and the knowledge gaps and research needs to effectively cope with each threat are discussed.
Based on soil resilience with respect to the impacts of the threats addressed, subsoil compaction is considered a severe threat to Danish soils due to frequent traffic with heavy machinery in modern agriculture and forestry. Soil erosion by water and tillage similarly compromises soil quality because degradation rates are much higher than generation of soil. The soil content of organic matter is critically low for a range of Danish soils, which should be counteracted by appropriate management options.