Peat

Jai Ganesh · Yesterday 23:14:56

Peat

Gist

Peat is the surface organic layer of a soil that consists of partially decomposed organic matter, derived mostly from plant material, which has accumulated under conditions of waterlogging, oxygen deficiency, high acidity and nutrient deficiency.

Peat is used as a fuel for heating and electricity generation, a soil conditioner in horticulture to improve moisture retention and aeration, and as a material for filtering and absorbing pollutants. It also has industrial and therapeutic uses, such as producing activated carbon and in certain medicinal baths.

Summary

Peat is partially decayed plant material that forms in waterlogged, low-oxygen environments like peatlands and bogs. It is a spongy, organic material, often consisting of sphagnum moss, that is crucial for various uses including horticulture, as a fuel source, and in scientific research, but its harvesting can harm ecosystems and contribute to climate change.

Formation and characteristics

* Formation: Peat forms when plant matter accumulates faster than it can decompose, which happens in waterlogged conditions that limit oxygen. Sphagnum moss is a very common component, but other plants like shrubs, trees, and herbs also contribute depending on the region.
* Characteristics: It is a dark, spongy, and spongy material with a high water retention capacity.
* Geographical spread: It is found globally, particularly in temperate, boreal, and sub-arctic regions, and in tropical coastal fringes.

Uses

* Horticulture: Peat is widely used in gardening and agriculture as a soil additive to improve water retention and aeration.
* Fuel: It can be used as a fuel source, especially in some parts of Europe, and is an intermediate stage in the formation of coal.
* Other: Peat is also used in the production of activated carbon, as a growing medium in horticulture, and as a filter or absorbent material.

Environmental impact

* Carbon sink: Peatlands are significant carbon sinks, storing large amounts of carbon, and restoring them can help mitigate climate change.
* Destruction: The destruction and drainage of peatlands for other uses, such as agriculture, release stored carbon and other greenhouse gases into the atmosphere.
* Biodiversity: Peatlands are unique habitats that support diverse ecosystems, and their destruction can lead to a loss of biodiversity.

Scientific interest

* Fossil record: Peat deposits have preserved ancient plant and animal remains, providing valuable insights into past ecosystems and geological history.
* Catalyst: Recent research has explored the potential of using peat as a low-cost catalyst in some chemical reactions, such as those in fuel cells.

Details

Peat is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. Sphagnum moss, also called peat moss, is one of the most common components in peat, although many other plants can contribute. The biological features of sphagnum mosses act to create a habitat aiding peat formation, a phenomenon termed 'habitat manipulation'. Soils consisting primarily of peat are known as histosols. Peat forms in wetland conditions, where flooding or stagnant water obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition. Peat properties such as organic matter content and saturated hydraulic conductivity can exhibit high spatial heterogeneity.

Peatlands, particularly bogs, are the primary source of peat; although less common, other wetlands, including fens, pocosins and peat swamp forests, also deposit peat. Landscapes covered in peat are home to specific kinds of plants, including Sphagnum moss, ericaceous shrubs and sedges. Because organic matter accumulates over thousands of years, peat deposits provide records of past vegetation and climate by preserving plant remains, such as pollen. This allows the reconstruction of past environments and the study of land-use changes.

Peat is used by gardeners and for horticulture in certain parts of the world, but this is being banned in some places. By volume, there are about 4 trillion cubic metres of peat in the world. Over time, the formation of peat is often the first step in the geological formation of fossil fuels such as coal, particularly low-grade coal such as lignite. The peatland ecosystem covers 3.7 million square kilometres (1.4 million square miles) and is the most efficient carbon sink on the planet, because peatland plants capture carbon dioxide (CO2) naturally released from the peat, maintaining an equilibrium. In natural peatlands, the "annual rate of biomass production is greater than the rate of decomposition", but it takes "thousands of years for peatlands to develop the deposits of 1.5 to 2.3 m [4.9 to 7.5 ft], which is the average depth of the boreal [northern] peatlands", which store around 415 gigatonnes (Gt) of carbon (about 46 times 2019 global CO2 emissions). Globally, peat stores up to 550 Gt of carbon, 42% of all soil carbon, which exceeds the carbon stored in all other vegetation types, including the world's forests, although it covers just 3% of the land's surface.

Peat is in principle a renewable source of energy. However, its extraction rate in industrialized countries far exceeds its slow regrowth rate of 1 mm (0.04 in) per year, and is also reported that peat regrowth takes place only in 30–40% of peatlands. Centuries of burning and draining of peat by humans has released a significant amount of CO2 into the atmosphere, contributing to anthropogenic climate change.

Formation

Peat forms when plant material does not fully decay in acidic and anaerobic conditions. It is composed mainly of wetland vegetation: principally bog plants including mosses, sedges and shrubs. As it accumulates, the peat holds water. This slowly creates wetter conditions that allow the area of wetland to expand. Peatland features can include ponds, ridges and raised bogs. The characteristics of some bog plants actively promote bog formation. For example, sphagnum mosses actively secrete tannins, which preserve organic material. Sphagnum also have special water-retaining cells, known as hyaline cells, which can release water ensuring the bogland remains constantly wet which helps promote peat production.

Most modern peat bogs formed 12,000 years ago in high latitudes after the glaciers retreated at the end of the last ice age. Peat usually accumulates slowly at the rate of about a millimetre per year. The estimated carbon content is 415 gigatonnes (457 billion short tons) (northern peatlands), 50 Gt (55 billion short tons) (tropical peatlands) and 15 Gt (17 billion short tons) (South America).

Types of peat material

Peat material is either fibric, hemic, or sapric. Fibric peats are the least decomposed and consist of intact fibre. Hemic peats are partially decomposed and sapric are the most decomposed.

Phragmites peat are composed of reed grass, Phragmites australis, and other grasses. It is denser than many other types of peat.

Engineers may describe a soil as peat which has a relatively high percentage of organic material. This soil is problematic because it exhibits poor consolidation properties—it cannot be easily compacted to serve as a stable foundation to support loads, such as roads or buildings.

Additional Information

Peat is a spongy material formed by the partial decomposition of organic matter, primarily plant material, in wetlands such as swamps, muskegs, bogs, fens, and moors. The development of peat is favoured by warm moist climatic conditions; however, peat can develop even in cold regions such as Siberia, Canada, and Scandinavia. Beyond its considerable ecological importance, peat is economically important as a carbon sink, as a source of fuel, and as raw material in horticulture and other industries.

The wetlands in which peat forms are known as peatlands. The peat formed and housed in these special ecosystems is the largest natural terrestrial carbon store, and it sequesters more carbon than all other vegetation types in the world combined. Peat is thus critical for preventing and mitigating the effects of anthropogenic global warming. Peatlands also help minimize flood risks and filter water, both of which are invaluable ecosystem services. Peat harvesting and land-use changes that damage peatlands are a major source of greenhouse gas emissions, and in the 21st century the use of peat increasingly has been discouraged in an attempt to protect these valuable ecosystems.

Peat formation

Peat moss (Sphagnum) is one of the most common constituents of peat. Peatification is influenced by several factors, including the nature of the plant material deposited, the availability of nutrients to support bacterial life, the availability of oxygen, the acidity of the peat, and temperature. Some wetlands result from high groundwater levels, whereas some elevated bogs are the result of heavy rainfall. Although the rate of plant growth in cold regions is very slow, the rate of decomposition of organic matter is also very slow. Plant material decomposes more rapidly in groundwater rich in nutrients than in elevated bogs with heavy rainfall. The presence of oxygen (aerobic conditions) is necessary for fungal and microbial activity that promotes decomposition, but peat is formed in waterlogged soils with little or no access to oxygen (anaerobic conditions), largely preventing the complete decomposition of organic material. The formation of abundant peat was not possible before land plants spread widely during and after the Devonian Period (beginning approximately 419.2 million years ago).

The formation of peat is the first step in the formation of coal. With increasing depth of burial and increasing temperature, peat deposits are gradually changed to lignite. With increased time and higher temperatures, these low-rank coals are gradually converted to subbituminous and bituminous coal and under certain conditions to anthracite.

Types and processing

Peats may be divided into several types, including fibric, coarse hemic, hemic, fine hemic, and sapric, based on their macroscopic, microscopic, and chemical characteristics. Peat may be distinguished from lower-ranked coals on the basis of four characteristics: peats generally contain free cellulose, more than 75 percent moisture, and less than 60 percent carbon, and they can be cut with a knife. The transition to brown coal takes place slowly and is usually reached at depths ranging from 100 to 400 metres (approximately 330 to 1,300 feet).

Peat is usually hand-cut, although progress has been made in the excavation and spreading of peat by mechanical methods. Peat may be cut by spade in the form of blocks, which are spread out to dry. When dry, the blocks weigh from 0.34 to 0.91 kg (0.75 to 2 pounds). In one mechanized method, a dredger or excavator digs the peat from the drained bog and delivers it to a macerator (a device that softens and separates a material into its component parts through soaking), which extrudes the peat pulp through a rectangular opening. The pulp is cut into blocks, which are spread to dry. Maceration tends to yield more uniform shrinkage and a denser and tougher fuel. Hydraulic excavating can also be used, particularly in bogs that contain roots and tree trunks. The peat is washed down by a high-pressure water jet, and the pulp runs to a sump. There, after slight maceration, it is pumped to a draining ground in a layer, which, after partial drying, is cut up and dried further.

Uses

Dried peat can be used as a fuel and burns readily with a smoky flame and a characteristic odour. The ash is powdery and light, except for varieties that have a high content of inorganic matter. Peat is used for domestic heating purposes as an alternative to firewood and forms a fuel suitable for boiler firing in either briquetted or pulverized form. Peat is also used for household cooking in some places and has been used to produce small amounts of electricity.

Peat is only a minor contributor to the world energy supply, but large deposits occur in Canada, China, Indonesia, Russia, Scandinavia, and the United States. In the early 21st century the top four peat producers in the world were Finland, Ireland, Belarus, and Sweden, and most of the major users of peat were these and other northern European countries. Peat is sometimes considered a “slowly renewable energy” and is classified as a “solid fossil” rather than a biomass fuel by the Intergovernmental Panel on Climate Change (IPCC). Although peat is not strictly a fossil fuel, its greenhouse gas emissions are comparable to those of fossil fuels.

In horticulture, peat is used to increase the moisture-holding capacity of sandy soils and to increase the water infiltration rate of clay soils. It is also added to potting mixes to meet the acidity requirements of certain potted plants.

Peat can be used in water filtration and is sometimes utilized for the treatment of urban runoff, wastewater, and septic tank effluent. It is also used to soften aquarium water and to mimic habitats for freshwater fish.

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#1 Yesterday 23:14:56

Peat

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