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In a compaction risk assessment three factors affecting soil compaction should be considered: (1) climate, (2) soil characteristics and (3) soil and water management (Canarache, 1991, Van Ouwerkerk and Soane, 1994, Van den Akker, 2002). In arable land with annual ploughing, both topsoil and subsoil compaction should be considered. From the short-term economic and environmental point of view topsoil compaction has more impact than subsoil compaction. However, from the sustainable point of view subsoil compaction is the most serious threat. This was also the conclusion of the Soil Strategy Working Groups (Van Camp et al., 2004). These insights are based on many long-term experiments, measurements of e.g. compactibility and data interpretation, including development of pedotransfer functions. The current assessment methodologies are adjusted to the national situations and available data and are not directly suitable for other countries. Recently, Horn et al., (2005), Simota et al., (2005) and Van den Akker (2004) used a deterministic approach in compaction risk assessment. This methodology allows constructing maps from farm scale up to European scale (Horn et al., 2005). An advantage of this deterministic method is that is can be used in every country, although it is doubtful whether pedotransfer functions for German soils can be used in a country with a completely different climate and/or soils. Jones et al. (2003) used readily available data from the European Soil Database and climatic data and made a provisional map of inherent susceptibility of subsoils in Europe to compaction. Further, Nachtergaele et al. (2002) developed an assessment approach based on expert judgement. In conclusion, most compaction risk assessment methods are based on a determination of the vulnerability of soil for compaction and only partly include other factors as climate and water- and soil use management. Also the resilience of soil for compaction is only partly included.
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