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Composts

Compost is an organic fertilizer produced in the process of decomposition of one or more organic components.

Composting is a biothermal process of mineralization and humification of one or more organic components, sometimes with the addition of mineral fertilizers and ameliorants, reducing the loss of nutrients, accelerating the decomposition of organic matter and increasing the availability of nutrients to plants.

The composting of organic waste is thermally decontaminated, with the temperature rising to 60 °C, which kills eggs and larvae of flies and helminthes, pathogenic non-native microorganisms, and suppresses weed seeds.

In organic composts, one of the components may act as an absorber of moisture, ammonia, and carbon dioxide, and it may decompose poorly without composting, such as peat, sawdust, household garbage, sod soil, and straw. Some components may be enriched with microflora, such as manure, slurry, feces, poultry manure, and contain large amounts of degradable nitrogenous and nitrogen-free organic compounds.

The degree of decomposition and homogeneity of the mass is the measure of compost readiness.

Peat-manure composts

Peat-manure composts are prepared near livestock buildings, in manure storages or in field stacks. The ratio of manure and peat depends on the quality of components and their availability in farms. In winter, the ratio is usually 1:1, in summer up to 1:3. Any peat with a moisture content of up to 60% is suitable for composting.

Layer composting is used at any time of the year. For this purpose, the peat is leveled by a layer of up to 50 cm on the prepared places with a width of 4-5 m of any length. Then it is covered with a layer of manure, which is again covered with peat. The layers of peat and manure alternate until the stack is 2 m high. The thickness of the layers depends on the ratio of the components. Top the stack with a layer of peat.

Focal composting is preferably used in winter. For this purpose manure on a prepared 50-60 cm layer of peat is placed in a continuous or discontinuous layer 70-80 cm thick and 1.0-1.5 m wide less than the underlying peat. If there is a shortage of manure, it is placed by intermittent layer (piles) with all sides covered with a layer of peat 50-70 cm. In winter, a stack of hearth compost is placed 1-2 days in advance, preferably during thaws, then the temperature inside does not drop below 25-30 °C.

In layer-by-layer and focal composting, to improve the quality of peat with manure, 1.5-3.0% (15-30 kg/t) phosphate meal is added to the mixture. This produces peat-manure-phosphoritic composts, which are as efficient as good manure with a content of 30-50%. Phosphoric flour is poured over layers of peat and manure.

When composting manure and peat with phosphoric flour, along with potash fertilizer at the rate of 1 ton of peat 5-6 kg of fertilizer. Depending on the acidity, lime fertilizer is added additionally, and phosphoric flour in this case is added to the manure, and potash and lime fertilizer – to the peat. The efficiency of such compost at equivalent rates is higher than that of manure.

Peat-slurry composts

Peat is composted with sewage, liquid and semi-liquid manure in the same way as with slurry.

Peat-slurry composts are prepared with any peat, except lime peat containing more than 5% of calcium, in winter in manure storages or next to livestock buildings, in summer – in field stacks and on drained peatlands. For 1 ton of aerated peat, depending on the moisture content, 1-3 ton of slurry and 1.5-2.0% of the mass of the compost phosphate meal are added. The peat is placed in two adjacent shafts with a trough-shaped depression between them, in which the slurry is poured.

After the absorption of slurry by peat, the mass is raked into stacks, covered with peat and compacted when the temperature reaches 60 ° C. Depending on the properties of components and the ambient temperature mass kept for 1-4 months. Used as a main fertilizer for crops in the same doses as the litter manure. Peat-slurry-phosphate composts are as effective as good manure.

Peat-fecal composts

Peat-fecal composts are produced by composting fecal matter with peat or straw, municipal garbage, and other low-degradable materials. Fast-acting organic fertilizer. Fecal matter contains on average 0.5-0.8% N, 0.2-0.4% P2O5 and 0.3-0.4% K2O. 70-80% of nitrogen is in the form of ammonia compounds and urea, phosphorus and potassium are in plant-available forms. Dried fecal matter (powders) contains 2% N, 4% P2O5 and 2% K2O. To reduce nitrogen losses during drying of fecal masses, 8-10% of dry peat powder is added to them. Powders are used under ornamental and bast crops at a dose of 2-3 t/ha. By efficiency are not inferior to equivalent doses of mineral fertilizers.

For sanitary, agronomic and environmental reasons fecal matter is better to use in the form of composts. For their preparation to 1 ton of lowland peat with a moisture content of 70% add 0.5 tons of feces to 1 ton of highland peat – 2 tons, when wet peat to 50% – up to 3.5 tons of feces. To decontaminate and reduce the loss of nutrients, composting must proceed at a temperature of 56-60 °C followed by compaction. The method of preparing compost is similar to that for slurry compost.

In the second year after laying, peat-fecal compost can be applied to any crops, except vegetable crops, at a dose of 10-25 tons/ha.

They often surpass manure in equivalent rates of nutrients by 30-50% in terms of efficiency.

Peat-mineral composts

Peat-mineral composts may contain lime, ash, phosphate meal, liquid ammonia and other mineral additives.

Peat-lime and peat-ash composts are prepared with acidic peat (pH of salt extract less than 5), pouring them over 15-20 cm layers when laying the stack. The dose of lime is calculated by 0.8 hydrolytic acidity (Hg) of peat, that is, when the moisture content of peat 60-70% on average 1-3% of the mass of the compost. The best form of lime fertilizer in this case is dolomite flour. Composts are kept before application for 4-5 months. Poor in potassium and phosphorus.

To enrich calcium, phosphorus and potassium composts are prepared with ash, with the additional neutralization of exchange acidity. The stack is prepared in the same way as with lime, adding 2.5-5.0% ash (25-50 kg/t) per 1 ton of aerated peat.

Peat-phosphate composts with a good mixing of the components already in a month of storage convert 30-60% P2O5 phosphate meal in the form assimilable for plants with a simultaneous reduction in the acidity of the peat.

To prepare these composts acid peat is used, which does not contain mobile forms of aluminum. Per 1 ton at 65-70% moisture content is added 10-30 kg of phosphate meal and kept 2-3 months.

Peat-lime and peat-phosphate composts are used in the same rates as manure. Their effectiveness increases when combined with nitrogen-potassium mineral fertilizers.

Peat-ammonia and peat-mineral-ammonia fertilizers (composts) are prepared by saturating the peat with liquid ammonia or its aqueous solution with the addition of phosphorus and potash mineral fertilizers. For these suitable peat ash content up to 25%, humidity 55-65% and the degree of decomposition of the lowland 15-20%, for the highland – 20-25%. For 1 ton of dry peat in the peat-mineral-ammonia fertilizers composition, 30-35 kg of phosphate meal or its mixture with superphosphate in the ratio 1:1, 10-12 kg of potassium chloride or other potassium fertilizers, 30-35 l of 25% ammonia solution or the equivalent dose of liquid ammonia by NH3 are used. In peat-mineral-ammonia fertilizers based on lowland peat, the amount of mineral components is reduced by 30-50%.

Composts prepared on peatlands

Preparation of compost on drained peatlands near fertilized fields reduces the cost and increases their efficiency.

The technology of compost preparation on peatlands is a combination of their treatment and loosening with the introduction of organic and mineral components, such as manure, slurry, fecal mass, lime, phosphate meal, with subsequent raking and compaction of mixtures in stacks.

When calculating the quantities of components and compost, take into account that at a mass of 1 m3 of 400 kg and the depth of the raked layer of 20 cm on each hectare of peatland for the season receive 800 tons of peat.

Peat-plant composts

Peat-plant composts are obtained by growing legumes or green manure crops on peatlands with subsequent plowing and preparation of stacks of the resulting mixtures of peat and plants.

Plant mass of green manure in the flowering phase is dug, crushed and plowed to a depth of 15 cm. After 2-3 weeks, the peat is disked, and the peat-sideral mass is raked into stacks 1.5-2.0 m high and left to stand for 1-2 months. Peat-plant composts are used for crops in the same doses as litter manure. In terms of efficiency in equivalent rates they are not inferior to semi-decomposed manure of dense storage.

Composts from household waste

In connection with the requirements for environmental protection and an increase in the amount of household waste, industrial methods of biothermal decontamination of waste and the preparation of composts on their basis are widespread. The average content of plant composts (% on dry weight) is 40-52 % of organic matter, 1-1.3 % N, 0.7-0.8 % P2O5, 0.4-0.6 % K2O, 3 % of crushed glass <15 mm, 4 % of foreign inclusions. The moisture content of the composts is 30-40% and the pH of the salt extract is 6.0-7.8.

In terms of the effect on the crop, compost from household waste is not inferior in equivalent rates to manure. Application requires agrochemical control for the presence of hazardous impurities.

Sources

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