NAREI in Focus has been sharing information about the different soil types in Guyana. The soil type in a particular area would determine the types of plants grown. In Guyana, there are two noticeable types of agriculture. Agriculture on the coastline is characterised by intensive cropping system of predominantly rice and sugarcane while on the hinterland there are staples such as ground provision and corn.

Peat or pegassy soil is made up of waterlogged partially-decomposed plant material including sphagnum moss and other acid-loving plants, which have built up over something like 10,000 years in poorly-drained wetland habitats. It extends along the coast of South America from the Amazon to the Orinoco. Also, the backlands of the North-West (Regions One and Two) are mainly peat and pegasse.

The organic matter in peat consists of plant residues that have undergone varying degrees of decomposition. Humus imparts a dark colour to peat. In the total peat mass, the relative concentration of the products of the decomposition of plant tissues that have lost their cellular structure is called the degree of peat decomposition.

A distinction is made between weakly decomposed (approximately 20 percent), moderately decomposed (20–35 percent), and strongly decomposed (more than 35 percent) peat. Depending on the conditions under which it was formed and on its properties, peat is classified as high-moor, transitional, or low-moor peat.

Peat has a complex chemical composition, which is determined by the conditions under which peat-forming plants originated, by the chemical composition of the plants, and by the degree of decomposition. By combustible weight, peat consists of 50–60 percent carbon, 5–6.5 percent hydrogen, 30–40 percent oxygen, 1–3 percent nitrogen, and 0.1–1.5 (sometimes 2.5) percent sulfur. The organic matter is made up of 1–5 percent water-soluble substances, 2–10 percent bitumens, 20–40 percent readily hydrolyzable compounds, 4–10 percent cellulose, 15–50 percent humic acids, and 5–20 percent lignin.

Much peat collection is done on a large industrial scale which totally destroys vast habitats which have taken centuries to form and so cannot be regenerated – they are gone forever. Living in these habitats are many rare and endangered species of plants and wildlife. Boglands are home for lots of different birds, butterflies and dragonflies. Water tables are affected by large-scale peat extraction and as the land dries up, the bog dries out and will die. Garden plants don’t actually need peat, whereas bog plants growing in the wild do.

The soils are organic accumulations of peat and other organic matter occasionally interlayered with clay and can be as deep as 9m. They are very acid and have extremely low fertility. Drainage, fertility and acid sulphate toxicity are the main limitations to agriculture. However, with the correct amount of liming this soil type is used to grow sugarcane and other vegetable crops in Guyana. The land cover is mainly natural vegetation of grassland and swamp forest.

Some economic benefits of peatlands

Peatlands bring enormous economic benefits to regions where they are found.
1. Peat is extracted for use as horticultural compost. It is highly sought after in commercial horticulture because of its high water retaining ability and flow of air.
2. Peat is used for fuel to generate electricity. It is also sold as briquettes for heating homes in cold climatic regions.
3. Peatlands are drained and used for agricultural purposes (pasture and crop production) and forestry.

Peat use for forestry and agriculture are beneficial but it alters the natural peatland hydrology. This causes oxidation of stored carbon, therefore, declining its organic matter content. During peat extraction, peat is drained and dried before storage or transportation for sale. These processes reduce the water content and encourage microbial decomposition of organic matter.