Histosols (from the Greek histos – tissue) are mainly composed of organic material in their upper portion. The Histosol order mostly contains soils commonly called bogs, moors, peatlands, muskegs, fens, or peats and mucks.
These soils form when organic matter, such as leaves, mosses, or grasses, decomposes more slowly than it accumulates due to a decrease in microbial decay rates. This most often occurs in extremely wet areas or underwater; thus, most of these soils are saturated year-round.
Histosols can be highly productive farmland when drained; however, draining these soils can cause them to decompose rapidly and subside dramatically. They are also not stable for foundations or roadways, and may be highly acidic.
Histosols make up about 1% of the world’s glacier-free land surface.