Classification Systems: Netherlands

Although people have always classified soils, it is only since themid 19th century that soil classification emerged as an important topic within soil science. It forced soil scientists to think systematically about soils and its genesis and developed to facilitate communication between soil scientists. It has also been the cause for much debate and confusion but two internationally accepted systems have emerged: Soil Taxonomy and the World Reference Base for Soil Resources (WRB). In addition, many national soil classification systems exist whose methods and approaches are based on one of the international soil classification systems or which have influenced these systems. Here we describe the Dutch soil classification system, which was essentially developed after the fourth International Congress of Soil Science in Amsterdam in 1950. The Netherlands is a low-lying country with the lowest point at nearly 7m below mean sea level just north of Rotterdam. The highest point is 321 m above mean sea level and located in the Southern part of the country. About half of the country is below sea level and would be inundated without dikes and dunes. It is also a wet country, and more than 90% of the soils have groundwater within 140 cm of the soil surface during winter. As a result, most Dutch soils are hydromorphic and require artificial drainage when taken in use. There is no consolidated rock and the parent material is alluvial (marine or fluviatile), or aeolian, glacial, or organic. About one-third of the country consists of embanked forelands from either the North Sea or the rivers Scheldt, Rhine, and Meuse; these polders have Holocene loamy and mostly clayey soils. About 40% of the Dutch soils have Pleistocene sands as parent material and 2% loess. Peat areas comprise about 25% of the Netherlands.