In the context of agricultural problem soils, Histosols are soils in which the organic matter content dominates the problems related to agricultural land use. Variations in these characteristics depend on the flora which has formed the Histosol. The occurrence of Histosols depends on a permanent plant cover and a shallow water table.
Natural drainage is very poor and the occurrence of water lenses within the peat is fairly common.
Histosols occur mainly in areas of high atmospheric humidity, low evapotranspiration and consequently wet soils or form in wet depressions and flat sites where run-off water accumulates and prevents the rapid decomposition of the plant litter. An estimated 40 million hectares occur in the tropics and subtropics, of which almost 25 million are in the coastal lowlands of Southeast Asia. If carefully reclaimed and managed, Histosols can be very productive under capital-intensive forms of arable cropping and horticulture. The removal of water through drainage is necessarily associated with shrinkage and compaction of the loose organic matter and subsequent considerable subsidence of the land surface. The low bearing capacity hampers also the construction of roads, buildings, and water works.