Soil, water and land use
The groundwater table ranges from > 1.5 m in the highest ridges to 50-100 cm in the lower ones. Between the ridges groundwater is found in the upper 50 cm.
At the higher positions the soil is drained well enough to grow crops and people have used these soils to produce food since the Middle Ages. As coversand is generally infertile, early farmers used a special way of preparing and applying manure, called ‘plaggen management’. The two figures below show how this plaggen management operated and what the resulting soil looks like.
Sod ‘plaggen’ cutting from the heath for use as bedding in stables. At night, the sheep were kept on this plaggen bedding, some sand, forest litter and sand were usually added, and this mixture was removed once or twice a year and spread on the arable fields, as manure. This special way of preparing and applying manure – ‘the plaggen agricultural system’ – was performed in the Netherlands until ~1900. From the 20th century onwards artificial fertilizers are used to fertilize arable fields.
The lower positions where the groundwater table can be found within the upper 50 cm are unsuitable to use as arable land. These imperfectly drained soils were used as pastures for cattle grazing and hay production.
The farms were always built at the boundary between low and high topographical/hydrological conditions: 1) to have easy access to groundwater, 2) to have a dry house during wet periods, and 3) to be near the arable fields as possible (everything had to be done with horse power!).
Typical northwestern European anthropogenic (i.e. man-made) plaggen soil.The thick dark topsoil is the result of adding plaggen manure to the soil for several centuries. Because the plaggen manure contained a fair amount of mineral particles (i.e. sand grains), the surface of the fields was raised. Nowadays these old arable fields (often still in use) are visible as low mounds in the landscape.