Peat specific weight: weight of 1 m³ and density

Peat is an organic substance of plant origin that people have used for many centuries. It is used as fuel, a component of soils and fertilizers, animal bedding and, in some construction solutions, as a thermal-insulation or fill material. By origin, peat is associated with the accumulation and incomplete decomposition of bog vegetation.

Without knowing the rich chemical composition and varieties of peat, of which there are now more than 35 types, the philosopher and historian Pliny wrote about it in the first years of our era as “combustible earth”. Only in the 18th century did the German researcher Degner, using a microscope, study the structure of peat and refute many mistaken judgments about its origin.

Peat formation

The main place where peat forms is peat bogs, but it is also found in river floodplains and valleys. Under high humidity, dying plants accumulate and decompose incompletely without air access. Decomposition occurs under the active influence of decomposer microorganisms, invertebrates and leaching.

In the upper peat-forming layer, at a depth of up to 0.9 m, the decomposition process is completed. About 30% of the decomposed biomass becomes peat; the rest is mineralized or washed out as various compounds. The formed peat gradually sinks below the peat-forming layer and is preserved without air access, retaining its properties for centuries.

Classification

Peats are classified according to phytomass composition, such as trees, grasses and mosses, and trophicity, meaning the amount of nutrients contained in the plants, into three categories:

• Raised peat. It has increased acidity and a low degree of decomposition. It is characterized by high moisture capacity and low ash content.

• Light raised, or transitional, peat. It belongs to the upper layer of the deposit; the degree of decomposition of plant residues is about 15%. The weight of 1 m³ of peat in such a layer is quite low, about 150-250 kg. In its natural state, it has high gas and water absorption capacity: 1 kg of such peat can absorb up to 10 liters of water.

• Lowland peat, or lower peat. This type includes ancient deposits up to 30 thousand years old. The substance has a fine, light and moist structure. The degree of decomposition of plant residues is more than 15%, and it has a high humus content; this is “mature” peat. The weight of a cubic meter is 350 kg/m³. The environment is slightly acidic, with a high content of nitrogen, phosphorus, potassium and other organic substances useful for garden plants.

• Fibrous peat is a special type of peat that contains plants with a pronounced fibrous structure. Such peat is not sifted and not molded like other types for further use; it is only crushed into small lumps.

How much does peat weigh?

As mentioned above, peat of different maturity levels has different degrees of water saturation and therefore different bulk weight. The same may apply to a product being sold. The table gives average theoretical peat weight data depending on moisture level.

The bulk weight of peat also depends on the degree of decomposition and group. At the same moisture content up to 85%, raised peats are heavier than lowland peats, but if moisture is above 85%, the weight of lowland peat will be higher.