Question

How is peat formed?

Answer 1

Before starting to plan the reclamation of peatswamps it is wise to gain a proper insight into the mode of formation of the deposits and the conditions which have led to their development. The recognition of the present stage of natural peat formation is also very valuable for assessing its potential for agriculture. Discussion of the formation or genesis of peat soils is made easier by first making a distinction between the actual formation of the organic materials, and the process of their accumulation. The former is caused by biochemical processes, whereas the latter is mainly a direct function of the environmental conditions, the climate and ecosystems (peatswamps, bogs or mires) in which the peat is formed, and the climate.
Organic materials only accumulate under certain conditions. For peat to form it is essential that the production of biomass (organic materials) is greater than its chemical breakdown. Not all organic materials are classed as peat. For practical reasons litter, being a special type of organic material, is excluded from our discussion.
Peats are generally considered to be partly decomposed biomass (vegetation). They show a wide range in degree of decomposition. Kurbatov (1968) briefly summarizes 35 years of research into the formation of peat as follows: “The formation of peat is a relatively short biochemical process carried on under the influence of aerobic micro-organisms in the surface layers of the deposits during periods of low subsoil water. As the peat which is formed in the peat-producing layer becomes subjected to anaerobic conditions in the deeper layers of the deposit, it is preserved and shows comparatively little change with time”. According to this theory the presence of either aerobic or anaerobic conditions decides whether any biomass will accumulate and in what form. Distinction is made by Kurbatov (1968) between forest peat which is more aerated and therefore more decomposed, and peats formed under swampy conditions with strongly anaerobic conditions. In forest peat, lignin and carbohydrates appear to be completely decomposed so it generally has a low content of such organic compounds, whereas under swamp conditions peats are characterized by high contents of cutin and the presence of much unaltered lignin and cellulose