- Mineral fertilizers
- Complex fertilizers
- Organic fertilizers
- Mineral fertilizers
- Complex fertilizers
- Organic fertilizers
Some industrial waste containing organic matter can be used as an organic fertilizer, thus achieving:
- increased crop yields;
- industrial production becomes more economical and gets rid of the costs of storage and disposal of waste.
Industrial organic waste used as fertilizer is divided into three groups:
- Waste requiring composting. This group includes wastes that are dangerous in sanitary, helminthological, entomological and phytosanitary respect, such as waste feathers, down, husks of oil seeds, cranberry and apple press cake, pomace from grapes, wine sludge.
- Wastes requiring advance application such as pulp and mash, grape seed grist, bristle factory waste, wool shop sweepings, cuttings from felt products, wool waste and wool dust. Often, these are wastes with a wide ratio of carbon to ammonium nitrogen (C:NH4). When applied directly to the soil before sowing, there is a temporary biological fixation of available soil nitrogen by microorganisms, which leads to nitrogen starvation of plants and reduces yields. Therefore, they are applied long before sowing – under the main tillage, before sowing nitrogen fertilizers are applied.
- Waste suitable for fertilizing without restrictions.For example, pork and beef slurry (processing waste), raw fish waste, wastes of skin dressing, glue production waste, horn and halalite chips, silk pupa, silk down, silkworm excrement, tobacco and tobacco dust, tobacco leaves after nicotine extraction, castor oil grist, castor oil cake, cotton, oilcake, rape seed press cake, supremium press cake.
The maximum application rates of industrial wastes in the soil are usually 80-100 kg of total nitrogen. Up to 6 t/ha can be applied by manure spreaders or in mixtures with manure and compost.
Wood bark and sawdust
Tree bark, which makes up 10-20% of the total tree volume and is accumulated at tree processing plants, can serve as an organic fertilizer. Tree bark and sawdust are used for mulching and as fertilizer, preparation of artificial soil for greenhouse and greenhouse farms, as bedding at poultry farms and poultry farms with subsequent use as fertilizer.
Stocks of woody greens in the Russian Federation exceeds 20 million tons per year, of which less than 10% is used. Woody bark contains the main nutrients, which in the process of mineralization become available to plants. It has a good humus-forming potential; in the process of mineralization carbon dioxide is released, thus improving air nutrition of plants.
Woody bark contains 33-35% cellulose, 22-30% lignin, 5.3-12 mg/100 g potassium, minor amounts of phosphorus. The strength, elasticity, high filtration capacity of bark improves the water-physical properties of the soil, its hard-to-degrade part enriches the soil with lignin and tannins involved in humus formation. The disadvantage of bark as a fertilizer is that it does not contain plant-available nitrogen. The ratio of carbon to nitrogen is 140:1. Ash content of pine bark is 2.8%, spruce bark 3.1-5.9%. Acidity is pH 4.8-5.7. Bark is biologically active: it contains a large number of bacteria and mold fungi.
Wood bark is plowed into the soil to a shallow depth. When you apply 125 m3/ha the soil structure improves, the moisture capacity increases. When non-composted bark is applied, nitrogen fertilizers are additionally required for normal life activity of microorganisms that contribute to bark decomposition. Decomposition of conifer bark crushed to 5 cm takes about 2 years.
Other uses of wood bark are composting with mineral and organic additives, and as biofuel, mulch and substrates in protected areas.
Methods of composting: layer-by-layer, focal, area-by-area.
Bark composting is most effective in bunches (piles) 3.0-4.0 m wide at the base, 1.5-2 m high, and at least 4.0 m long. When composting in winter, to avoid freezing, the height of the pile is increased to 2-5 m and the length to 10 m. The weight of the stack is 100-120 tons, as the weight of less than 60 tons the stack freezes. The temperature during the composting period reaches 40-60 °C.
The finished compost must contain at least 80% of organic matter per dry weight at moisture no higher than 60%, 10-15% of humic acids from the total organic matter, pH of the water extract – at least 5.5, the ratio of C:N – no more than 30:1, nitrogen, phosphorus and potassium – respectively 3.0%, 0.1% and 0.1% of dry weight. The density is 0.18-0.3 g/cm3, a lumpy structure and moisture capacity of 250-350 g of water per 100 g of dry matter. Due to the calcium content compost is a meliorant for acidic soils. Compost helps to reduce the incidence of root rot and suppresses the development of nematodes.
The use of bark-based composts can provide greenhouse and greenhouse facilities with high-quality soils.
Sawdust has a similar use in agriculture. All kinds of sawdust improve the physical properties of soils, increase porosity and water retention capacity, reduce the density of heavy clay soils. As well as wood bark, sawdust contains little nitrogen, so the most effective way to use them is composting with nitrogen fertilizers.
Hydrolysis lignin is the main waste product of the hydrolysis industry, which makes up to 40% of the weight of the feedstock. When unloaded from the hydrolysis unit, it retains the shape of particles of the feedstock with a dark brown color. According to the chemical composition is a complex of substances, the bulk of which – the products of condensation and polymerization of natural lignin. Also present are non-hydrolyzable polysaccharides, unsaturated sugars, humic substances, organic acids, sulfuric acid, and ash elements. The first two, lignin and polysaccharides, account for 84-91% of the weight of hydrolyzed lignin. Polysaccharides account for 24-45% and lignin for 39-70%. Lignin has an acidic reaction, with a moisture content of 63-75%.
Table. Agrochemical indices of hydrolysis lignin (in recalculation on dry matter) (Tsurkan M.A., Russu A.P., 1980).
|Ash content, %|
|Total carbon, %|
|Humic acid carbon, %|
|Fulvic acid carbon, %|
|Total nitrogen, %|
|Nitrate nitrogen, mg/100 g|
|Ammonium nitrogen, mg/100 g|
|Nitrogen easily hydrolyzable, mg/100 g|
|Total phosphorus, % P2O5|
|Total potassium, % K2O|
|Total calcium, % CaO|
|Total sulfur, % SO4|
Among the nutrients it contains a large amount of sulfur and calcium. Phosphorus and potassium contain on average 0.06% and 0.09% of dry matter, respectively. The content of total nitrogen in hydrolysis lignin is 0.34-0.39%, 14% of which is hydrolysable. The C:N ratio ranges from 75:1 to 117:1.
The return of organic matter lignin into the biological cycle contributes to the protection of the environment from pollution and increases the total production of local fertilizers.
The disadvantages of using lignin as a fertilizer are related to its acidity and low content of nitrogen, phosphorus and potassium. The positives are: improvement of air permeability, porosity, soil structure and physical and chemical properties. It has the ability to adsorb the nitrogen of mobile nitrogen-containing fertilizers, enter with it in a chemical bond, thereby reducing the washout of nitrogen from the upper layers of the soil and increasing the rate of plants.
An industrial method of composting lignin with mineral fertilizers and treating the compost with an ammonia solution before applying it to the soil has been developed. To prepare composts, lignin is pre-neutralized with dolomite flour at the rate of 30-35 kg per ton of fertilizer. The most effective lignin-manure composts have a ratio of manure and lignin of 1:1. For the preparation of 100 tons of compost, 48.2-48.5 tons of lignin with a moisture content of 60%, 1.5-1.75 tons of dolomite meal and 50 tons of manure are used. To accelerate maturation, the piles are made to a height of 1.5 m and the mixture is well mixed. In the raw mass of the compost contains: N – 0,36%, P2O5 – 0,32%, K2O – 0,34%, pH 5.7. The efficiency of the lignin-manure compost is not inferior to the peat-manure compost.
Household waste and municipal garbage, such as kitchen waste, paper, rags, dirt, dust, ash, can be comparable to litter manure in terms of nutrient content and fertilizing qualities. The rate of their mineralization in the soil depends on the amounts and ratios of the components. With large amounts of food waste and dust, litter decomposes quickly; it can be applied as fertilizer without composting. If paper and rags predominate, the rate of decomposition is lower, so composting is more effective.
Household waste is 0.15-0.25 t/year per capita in Russia. They often include up to 30-40% organic food components and 20-30% paper. The chemical composition of household waste varies greatly. On average they contain 40-70% organic matter, 28-30% ash, 23-37% carbon, 0.75-1.15% nitrogen and 2.0-5.5% calcium. Per dry weight: 0.6-0.7% N, 0.5-0.6% P2O5 and 0.6-0.8% K2O.
Household waste is highly biologically contaminated, can pose an epidemiological hazard, and requires decontamination. This problem is solved by disinfection in landfills, incineration, biothermal disinfection in the production of compost at the plants.
Decontamination of garbage by long-term composting in landfills, although common, but in sanitary and hygienic terms – unpromising. Disinfected garbage without removal of impurities from the landfills is not suitable for use as a fertilizer. The use of such garbage leads to the littering of fields with metal, glass, bricks, plastics, plastic film and other wastes.
A better way to decontaminate and recycle household waste is field composting.
Industrial biothermal decontamination and processing into compost and biofuel of household waste is now spreading.
Household waste arriving at the plant is subjected to separation: ferrous metals are extracted by electromagnetic belt separators, then the waste is treated with air and water at a temperature above +40 ° C. The garbage is self-heated to 60-70 ° C and decontaminated for 3 days.
The resulting compost contains 40-52% of the dry weight of organic matter, 1.0-1.3% – nitrogen, 0.8-0.7% – phosphorus and 0.4-0.6% of potassium. The presence of up to 3% of glass with a particle size of not more than 15 mm and 4% of foreign inclusions is allowed. The moisture content is 30-40%, and the pH is 7.8.
Industrial compost from municipal solid waste can be applied to fruit crops in an amount of 50-150 tons/ha, grapes – 20 tons/ha, cereals – 20-50 tons/ha, sunflowers, corn – 30-100 tons/ha. Yield increase depending on culture and soil is 10-50%. Compost is safe in sanitary-hygienic, helminthological and entomological respect. Autumn application is preferable. Due to the lead and zinc content in the compost, their use for vegetable crops is prohibited.
As a pre-sowing fertilizer for the main tillage, garbage without pre-composting can be applied to different crops in doses of 20-60 t/ha. In protected ground it is effective in greenhouses and greenhouses as a biofuel, after which it becomes a homogeneous, crumbly and decomposed organic fertilizer for open ground. After composting or use in greenhouses, the decomposed homogeneous trash is applied to crops in doses up to 20 t/ha.
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.