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Peat

Peat – organic fertilizer, which is plant residues of varying degrees of decomposition.

The area of peatlands in Russia is over 80 million hectares, the total reserves of peat on air-dry matter amount to 160 billion tons, which is equal to more than 1/2-2/3 of the world reserves. 

Peat reserves in Russia are distributed as follows: about 70% are located in the West Siberian region, 13% in the Northwest region, 6% in the Urals, and 3-4% each in the Far Eastern, Central and East Siberian regions. 50.6% of the deposits are represented by high-moor peat, 31.1% by low-moor peat, and the rest by transitional peat.

Types of peat are unequal in quality, so the ways of its use as a fertilizer are different. All peat bogs and extracted peat are divided into highland, lowland and transitional peat. Depending on the degree of peat decomposition, determined by the content of humified substances, peat is distinguished:

  • slightly decomposed – degree of decomposition 5-25%;
  • medium-decomposed – 25-40%;
  • highly decomposed – more than 40%.

Types of peats

The type of peat is determined by the location of the bog in terms of relief elements and the composition of vegetation.

The high-moor type is formed on elevated elements of the relief from white sphagnum mosses with small amounts of moss-grass, Ledum, blueberry, cranberry and other plants undemanding for nutritional elements. Sphagnum top peat is the most poor in elements, very acidic, low-humic (up to 20%), low ash, the most moisture- and gas-intensive, contains up to 40% hemicellulose and cellulose. It is the best litter material for animals and a component of composts.

The lowland (low-moor) type is formed under the influence of groundwater with high mineral content in the depressions of the relief with sedges, reeds, reeds, horsetails, green hypnum mosses, alder, willow, birch and other moisture-loving and more demanding to nutrients plants.

Lowland peat is the remnants of herbaceous and woody vegetation, contains more nutrients, is less acidic, highly ashy, contains up to 50% of humic substances, is highly humic, enriched with lime and phosphorus. When drained it is suitable for cultivation of vegetable, fodder and other crops, can be used as an organic fertilizer in the open and closed ground, for the preparation of pots and as a component of composts.

Transitional type is intermediate between the high-moor and low-moor types. And the lower layers of transitional peat are usually closer to the lowland, the upper ones to the high-moor.

The type of peat is determined by low-decomposed residues of plants – peat formers, which content is more than 20% of the dry matter mass.

Composition and properties of peats

The botanical composition, degree of decomposition, ash content, nutrient content, acidity, moisture capacity and cationic absorption capacity (CAC) are important for agrochemical assessment of peat quality. Botanical composition determines the ash content, acidity, degree of humification, provision with nutrients.

The degree of decomposition is an indicator of the agronomic use of peat. Weakly decomposed peat is used mainly for animal bedding, medium-decomposed peat after extraction and ventilation is used as fertilizer, for compost preparation or for cultivation of crops after hydromelioration of peatlands.

Ash content of peats can be normal, i.e. up to 12%, and high – more than 12%. High ash content, as a rule, lowland peats (20-30%) are obtained in the presence of sand, clay, increased quantities of lime (peat-tuff) or vivianite in them. Increased ash content at the expense of calcium and phosphorus (vivianite) increases the value of peat. Peat turf and vivianite peat without composting is used as a direct fertilizer as well as for the liming of acidic soils and for phosphoritization.

Table. Agrochemical indicators, % on the absolute dry weight of different types of peat[1] Yagodin B.A., Zhukov Y.P., Kobzarenko V.I. Agrochemistry / Edited by B.A. Yagodin. - Moscow: Kolos, 2002. - 584 p.: ill.

Type of peat
Ash
рН
Organic matter
N
P2O5
K2O
CaO
pH of the salt extract[1]
Hг
T
H2O
KCl
mg⋅eq/100 g dry weight
Lowland peat
8-15
5,5-7,0
4,8-5,8
85-92
2,5-3,5 (2,3-3,3)
0,2-0,6 (0,12-0,5)
0,15-0,20 (< 0,15)
2,0-6,0
4,7-5,5
70-80
160-250
Transitional peat
5-8
4,0-6,0
3,5-4,8
90-95
1,2-2,5 (1,0-2,3)
0,10-0,25 (0,1-0,2)
< 0,15 (0,1)
0,2-0,4
3,5-4,7
-
-
Highland peat
< 5
3,0-4,5
2,6-3,2
95-98
0,7-1,5 (0,8-1,2)
< 0,15 (0,06-0,12)
< 0,10
< 0,4
2,8-3,5
120-180
100-200

Nitrogen contained in peat is in organic compounds that are poorly absorbed by plants. Therefore, the use of peat in its pure form is ineffective. The costs of extracting and using peat in its pure form are often not repaid by an increase in yield.

The content of nutrients decreases in the transition from lowland to highland peat. Peat contains most of the nitrogen, and most of it is contained in the organic form and becomes available to plants only after mineralization, which in acidic environments almost does not proceed, but can be accelerated after neutralization and at composting with manure, slurry, poultry manure, feces.

The content of phosphorus in peats is small, with 2/3 soluble in weak acids and available to plants.

Potassium content in peat is the least, and only half of the gross content is available for plants, of trace elements – the least of all copper. Therefore, when cultivating crops on drained peatlands, they are fertilized with potassium and copper fertilizers.

The acidity of peat is an indicator of the type and methods of its application. When the acidity is less than 5.5 lowland decomposed peat is not suitable for use as a fertilizer without prior composting with lime, phosphate flour, ash, manure, slurry. All peats can, when composted with phosphate flour, convert phosphorus into forms available to plants.

Raw peat contains 80-90% water. With one ton of such peat 100-200 kg of dry organic matter is applied. Raw peat does not allow quality uniform application to the field. Too dry peat is also inexpedient to use, as it has a high absorption capacity. Peat with moisture content of 35-40% absorbs moisture of the soil layer, which leads to soil drying and causes moisture deficiency. In the dry arable layer the speed of decomposition of peat is very slow.

The absorption capacity is important when peats are used as bedding material for birds and animals, due to the absorption of moisture and gases, in particular ammonia. The maximum moisture absorption capacity of upland peats is 1000-1800% on the dry mass, and gradually decreases in the transition to lowland peats, remaining at 500-1000%. The absorption capacity of all types of peats is higher than that of heavy chernozem. It is also important for the storage in peats in the absence of storage facilities of significant amounts of liquid ammonia of industrial production and local preparation of peat-ammonia fertilizers (PAF).

Application of peat and peatlands

Peat is used:

  • for litter for livestock and poultry;
  • as a component of composts;
  • for the preparation of peat-mulch pots and cubes;
  • as a mulching material;
  • substrate for cultivation of crops in an indoor environment;
  • as organic fertilizer.

Upper sphagnum peat with degree of decomposition up to 25%, ash content up to 10-15%, moisture content of 50%, content of wood particles up to 6 cm in size up to 10% is used primarily as litter. Gypne, sedge and reed types of peat for these purposes are used rarely and only in slightly decomposed (up to 20%) state.

As a direct fertilizer, lowland peat rich in lime or phosphorus is used, mainly on light soils, with pH over 5.5, ash content over 10%, including СаО over 4% and the degree of decomposition over 40-50%. Doses of pure peat 50-100 t/ha can be reduced by its combined introduction with slurry (5-10 t/ha), semi-liquid manure, faeces, poultry manure. Rates of peat-tuffs are determined by the content of CaO, vivianite peats – by the content of P2O5.

Surface aerated lowland and transitional peats with a layer of up to 5 cm in the inter-row plantings of berry, fruit and vegetable crops are used as mulching material. Mulching contributes to improvement of water, air, heat and nutrient regimes in the upper soil layer, suppresses growth and development of weeds and formation of soil crust.

The use of peatlands after drainage for cultivation of agricultural crops is possible without and after removal of the top peat layer, but in the latter case the thickness of the peat layer should be at least 50 cm.

Peat soils need liming.

Since peat soils are poor in phosphorus, potassium and copper, mineral fertilizers are applied when cultivating crops. On the newly developed peatlands and nitrogen fertilizers are effective, and on the developed after 8-10 years, they often lose effectiveness. Since peatlands are poor in microflora, the newly developed to accelerate the decomposition of organic matter is advisable to make a small doses of fertilizers rich in microflora, such as feces, poultry manure, manure, slurry, bacterial preparations. Rates of macro- and microfertilizers are established taking into account the needs of crops and planned yields.

Application of peat for composting

To increase the availability of peat nitrogen for plants, it is composted with biologically active components or used for livestock litter.

Composts are placed in round piles 3-4 m in diameter at the base, 1-2 m at the top and up to 1.5 m high, or in stacks 1.5-2 m wide, 1 m high and 1 m long – depending on the amount of material. Loose materials are tamped down, covered with soil, straw or peat, to prevent drying out.

In all composts any peat is the most valuable component, but it is better with a higher degree of decomposition (more than 20%), ash content up to 25% and the content of wood inclusions up to 10%, and with lime, ash and phosphate flour – with a pH less than 5 and ash content less than 10%.

To make seedling cubes and pots to peat add compost, humus, poultry manure, silt, sod soil, mineral fertilizers, lime or ash. For this purpose, lowland and transitional peat with a neutral or weakly acidic reaction, the degree of decomposition of 30-40% and ash content up to 15% are better suited.

Peat-manure composts

When composting peat with manure, excessive acidity of peat is eliminated, conditions for the course of biological processes are created, decomposition of peat is accelerated, the amount of mobile nitrogen available to plants increases. Microbiological processes proceed faster if the temperature rises to 60-65 ° during composting in the stack, so unlike manure, stacks of peat-manure composts are not recommended to compact. Composting peat with manure also contributes, due to its high absorption capacity, to the preservation of ammonia of manure.

Peat-manure composts are prepared in the field, at the place of application, less often near livestock buildings or in manure storages. For one weight part of manure in winter time take 1 part of peat; in spring-summer harvesting – 1-2 parts. All types of peat, the humidity of which is no more than 60%, are suitable for the preparation of peat-manure composts.

Adding phosphate meal to peat-manure compost is recommended in an amount of 2-3% of the mass of the compost. If the compost is prepared for application to potatoes on light soils, potash fertiliser in an amount of 0.5% of the mass of the compost must also be added, provided it is well mixed and then evenly spread in the field.

Preparation of peat-manure compost is carried out by different methods.

The layered method can be used at any time of the year. To do this, unload the peat at the site and bulldoze it with a layer of 40-50 cm. Manure is taken out onto the peat and leveled out by a layer of 25-30 cm. The subsequent layering of peat and manure in stacks is done by loaders. The stack is completed with a layer of peat with a thickness of 40-50 cm. The finished stack has a width at the base of 3-4 m, a height of 2 m, any length. In winter, to avoid freezing of manure, stacking is carried out within 1-2 days.

Focal method of stacking differs from layer-by-layer method in that the manure is placed on the peat cushion in separate piles at a distance of 1 m from each other, the gaps between them are filled with peat. Laying is carried out by the same machines. The focal method of composting provides a better warming of the compost in winter.

The site method consists in creating a peat cushion with a layer of 25-30 cm, followed by laying and leveling the manure. Then there is 2-3 times discing with a heavy disc harrow to mix the manure with peat, the mixture is raked by bulldozer into stacks for composting. This method is more suitable for composting in the spring-summer and autumn periods.

Properly prepared peat-manure composts have the same effect as manure.

Peat-slurry and peat-fecal composts

To preserve the nutrients of slurry and feces, and to increase the fertilizing effect of peat, peat-slurry and peat-fecal composts are prepared. It is better to prepare them in spring and summer. To do this, the peat is placed in two continuous adjacent rolls so that between them formed a trough-shaped depression. The thickness of the layers at the contact points of the shafts should be 40-50 cm. End walls are made manually or by bulldozer. Slurry or feces is poured into this pit from a tanker or a slurry spreader. The liquid should not overflow or leak through the side walls of the pit. After the slurry or faeces have been absorbed by the peat, the mass is raked into stacks without compaction.

Per 1 ton of peat, depending on the type and moisture content, 0.5-1 tons of slurry or faeces are taken. As a rule, fecal matter contains 1.5 times more nitrogen than manure. Phosphate meal should be added to the peat-slurry compost in an amount of 1.5-2% of the mass of the compost. All types of peat, except carbonate peat with a high lime content, are used for the preparation of peat-slurry and peat-fecal composts. They are prepared more often in the field at the place of application. Peat-slurry composts in the spring and summer mature within 1-1.5 months.

Such composts are also prepared on drained peatlands, near the location of sources of faeces and fertilized field.

For this purpose, directly on the peat field after drying peat crumbs in layers-surface method rake in swaths, make feces at a ratio of 1:1. If there is a shortage of faecal matter, 3-5 tons of lowland peat per 1 ton, but this compost is less concentrated, and its doses of making twice as much. The compost is suitable for use after a few months, and it has a homogeneous appearance, easily crumbling.

During the preparation of peat-fecal compost temperature must rise to 55-60 °C, in order to under the influence of high temperature to destroy the eggs helminths and pathogens. If the temperature in the toro-fecal compost does not rise to 55-60 °C, you can use it for potatoes and vegetable crops only in the second year after putting it in.

As a rule, peat-fecal and peat-slurry composts are not inferior to manure in terms of efficiency. They have the best effect on the harvest in combination with mineral fertilizers. Under cereals as a basic fertilizer contribute 10-15 t/ha of peat compost, under potatoes, silage and other forage crops – 20-25 t/ha, vegetable crops – 30-40 t/ha.

In the absence of peat, faeces can be composted with soil. To do this, lay faeces and dry soil in layers at a ratio of 1:1.

Sources

Yagodin B.A., Zhukov Y.P., Kobzarenko V.I. Agrochemistry/Under ed. B.A. Yagodin. – M.: Kolos, 2002. – 584 p.: ill.

Agrochemistry. Textbook / V.G. Mineev, V.G. Sychev, G.P. Gamzikov et al. – M.: Publishing house of the All-Russian Scientific Research Institute named after D.N. Pryanishnikov, 2017. – 854 с.