The age of the oldest polders in the Netherlands is historically proved to be about 1000 years. Soil development varies widely depending upon soils development before embankment, drainage, land use, and age and composition of parent materials. Nearly all the pedological processes may be included into the initial soil formation called “ripening.” The parent materials are divided into three main groups: peaty, calcareous mineral, and noncalcareous mineral. The behavior of each group under the ripening process is very different. Ripening causes important changes like subsidence, increased permeability, and development of cambic horizons. Such widely different soils as, for example, Eutrochrepts, soils with natric horizons, or acid sulfate soils may be formed by ripening.
Umbrie and Mollic epipedons may form rapidly by decomposition of organic surface layers.
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