The study Soil and water in a changing environment, carried out on behalf of the Environment Directorate-General of the European Commission, gathers information on the dynamics between soil and water, focusing particularly on soil water retention (SWR).
Soil water retention can be defined as the capacity of the soil to capture, store and/or release water. It is a key soil property and significant component of the water cycle that greatly affects soil functioning and therefore its capability to deliver a range of ecosystem goods and services that are vital both for human activities (e.g. agriculture) and to nature (e.g. providing habitat for different species). It is defined to great extent by soil types, depending on its texture, organic matter content, structure or depth, for example. Moreover, also the type of land use and management practices significantly influence that capacity.
A brief analysis of current major threats to European soils is enough to see that those soil threats will usually have a close link with water retention. Erosion, for example, is much more likely to occur in dry soils. And higher compaction, or sealing, prevents water from infiltrating the soil and therefore decreases its retention capacity. Consequences of changing retention capacities of soils together with the impact of changing weather patterns are already presently felt at European level, with some regions being particularly affected. In particular, the catastrophic flooding that recently occurred in 2002 and 2013 in Central and Eastern Europe, and in 2007 and 2014 in Western Europe, highlight the urgency to better consider the impacts of our economic development on soil water retention capacity and the resilience of natural ecosystems.
The study shows that several opportunities exist in land use planning, urban design and in the agriculture and forestry sectors to preserve or even enhance soil water retention and reduce the costs of associated damages. This is especially important in Mediterranean countries, which are particularly vulnerable, and in areas subject to high soil sealing (e.g. densely populated and industrial areas) or rapid urban sprawl, such as coastal areas. The agricultural sector in particular, through wide variety of agricultural practices that can be implemented within a same land use type, represent a key opportunity and many beneficial practices still show an untapped potential for development across the EU.
Examples of key principles identified are: