Which one of the following soils is characterized by very high content of organic matter?

Histosols are the soil order characterized by a very high content of organic matter, typically containing at least 20 to 30% organic matter by weight. These soils are primarily composed of organic materials that accumulate in wetland environments such as bogs, marshes, and swamps [2]. The waterlogged and often acidic conditions in these environments inhibit the decomposition of plant material, leading to the formation of peat [1]. In contrast, Vertisols are defined by high clay content and swelling-shrinking properties, Gelisols are defined by the presence of permafrost, and Spodosols are acidic forest soils characterized by the accumulation of aluminum and iron oxides [3]. Histosols are globally significant for carbon storage, particularly in the Northern Circumpolar Permafrost Zone, where they are often perennially frozen [1].

Sources

1. [1] https://openknowledge.fao.org/server/api/core/bitstreams/03d6d88c-abd9-4dea-b8f9-8376e38d70f8/content
2. [2] https://www.lancaster.ac.uk/lec/research/soil-science-knowledge/twelve-soil-orders/
3. [3] https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/gelisol