Classification and application of mineral fertilizers
The land, endowing us with generous harvests of fruits, vegetables, cereals, is greatly depleted. Cultivated lands - fields, orchards, backyards and summer cottages - do not have the opportunity to rest, recuperate, and maintain fertility. All this should be done by a person, artificially introducing into the soil the organic and mineral elements consumed by it. Sources of these elements are organic and mineral fertilizers. We will talk about their classification and types in the garden later in our article.
Complex mineral fertilizers in horticulture
A good fertile soil should include a certain amount of micro and macroelements that provide adequate nutrition, development and fruiting of plants growing on these soils. The absence of this or that useful substance, as well as oversaturation, has a very detrimental effect on the state of crops, their yield. To prevent this from happening, the soil and crops growing on it are fed with mineral supplements.
Mineral fertilizers are balanced mixtures of mineral salts in the most accessible form for planting.
It often happens that the absence of just one element interferes with the full absorption of other nutrients present in the soil in sufficient quantities. To fill the gap, complex mono-feeding is used. For example, sandy soils often need additional fertilization with magnesium, and manganese is lacking on chernozem lands. For all crops, regardless of the growing soil, nitrogen is vital.
The most important thing is that the chemical composition of salts and compounds that make up mineral fertilizers is specially selected so that plants easily absorb nutrients and quickly react to their presence. For each, there are certain rates and terms of application, and which one is necessary for your land plot can be determined by the condition and appearance of the plantings, the quality of the soil, as well as the expected result.
Plant and Soil Condition as Indicator of Mineral Deficiency
Nitrogen, potassium, phosphorus are the basis of plant crops nutrition. It is these elements that most of all have an impact on the active growth and harmonious development of fruit trees, shrubs, vegetables and flowers. And, accordingly, their lack affects the vegetation and the appearance of trees and grasses.
Lack of nitrogen
As you know, nitrogen is the main element that ensures the growth of garden and vegetable crops throughout the entire vegetative cycle, and it can be absorbed exclusively from the soil (in the air, 78% of nitrogen is in a form inaccessible to plants).
Therefore, it is necessary to constantly maintain the rate of nitrogen content in the soil. Its lack is manifested already at the very beginning of spring in the early stages of development of crops, seedlings: too weak stems, small leaves, a very small number of inflorescences. Further, the lower leaves begin to brighten - first the veins, and then the tissues around them, gradually die off, and the next leaves weaken. Plants lack the vitality to grow and form ovaries.
Lack of potassium
It can be seen closer to the middle of vegetative development - the green mass acquires an unnatural turquoise-blue hue, the leaves become faded, the natural bright greens are not pleasing to the eye. Then, brown spots appear along the edge of the leaf, the tissues gradually die off (dry out). The stems are thin and prone to lodging, growth is slow, there are few fruits and they develop very poorly.
Leaves on tomatoes, carrots acquire "curliness", fruit trees bloom too abundantly, but the fruits are small and ugly. Potassium deficiency also affects root development. Most often, acidic soils are poor in this element.
Leaves on tomatoes, carrots acquire "curliness", fruit trees bloom too abundantly, but the fruits are small and ugly. Most often, acidic soils are poor in this element.
Reduced phosphorus content
Symptoms resemble a lack of nitrogen: stunted growth, thin lifeless stem, late flowering and fruit formation, as well as their ripening, falling of the lower leaves.
Only in contrast to nitrogen, the lack of phosphorus causes an unnatural darkening of the stems and leaves, their partial color in purple and burgundy shades. Phosphate starvation also indicates an increased acidity of the soil, and is most pronounced on tomatoes, black currants, apple trees, and peaches.
Nitrogen, phosphorus and potash fertilizers
All fertilizers that are required for application to the soil and for plants can be divided into organic (fresh or rotted manure, compost, bird droppings) and mineral fertilizers. The latter, in turn, are subdivided into simple and complex.
Simple mineral remedies contain salts of only one essential substance, in a form readily assimilable by plants and usually highly soluble in water:
- nitrogen: the most commonly used forms are sodium nitrate, calcium nitrate, alkaline dressings used on acidic soils), ammonium nitrate (acid fertilizer for neutral and alkaline soils), urea (as a liquid dressing, it is quickly absorbed by the root system of plants and acts very effectively);
- potash fertilizers in the form of potassium sulfate are necessary for all horticultural crops to increase resistance to typical diseases, frost and heat, as well as the accumulation of starch and sugar in fruits. The most acceptable form for plants is potassium sulfate. Potassium salt and potassium chloride contain a certain amount of harmful impurities, therefore, it is advisable to use it only in the fall, so that a significant part of the harmful impurities is washed out with snow by spring;
- phosphorus fertilizing required during the flowering period, the formation of ovaries, fruit ripening Phosphoric flour, simple or double superphosphate is used on acidic soils, since they show positive properties only by interacting with acids. They contain sulfur and gypsum as auxiliary substances, which neutralize acidic soils.
Complex mineral supplements consist of two or more components, may include a number of trace elements.
Naturally, it is much more profitable to use such balanced additives, immediately saturating the soil with a whole complex of nutrients. But the choice should be approached more carefully, having established exactly what elements your plants lack. The most common names are ammophos, nitrophoska, nitroammophoska, diammophoska. Instructions for the use of these drugs are always printed on the packaging.
Dolomite flour and instructions for use
Dolomite flour - natural mineral fertilizer, which is obtained by grinding dolomite into the finest flour. It contains useful elements such as calcium and magnesium in the form of carbonates (calcium and magnesium salts CaCO3, MgCO3). This form saturates the missing nutrients, but prevents their excessive accumulation in fruits and vegetables.
Limestone dolomite flour, deoxidizing the soil, also contributes to the assimilation of those elements that are already in it, but due to high acidity are inaccessible to plants, do not split. Flour is a type of mineral dressing. In addition, fertilization negatively affects some types of weeds and pests. The list of positive qualities of this deoxidizer is quite long:
- improves the chemical, physical and biological (promotes the development of healthy microflora) soil structure;
- promotes a more complete assimilation of nutrients when applying any other mineral fertilizers;
- promotes the formation of a stronger and more developed root system of plants, its enhanced nutrition;
- cleans plants from radionuclides;
- helps to increase the keeping quality and safety of the crop;
- destroys terrestrial insects by dissolving their chitinous shell.
Another important advantage is a very low price and complete harmlessness to humans and other living organisms (except insects). To improve all the qualities of the soil, it is necessary to pour the correct fertilizer from dolomite every year, preferably 2-3 weeks before the start of planting work.
The value of adding mineral supplements to the garden
Nitrogen, potassium and phosphorus are the most basic components for plant nutrition in horticulture: nitrogen makes them strong, strong; potassium makes the fruit appetizing and beautiful, while phosphorus stimulates the growth of the root system. These dressings make the land fertile, allow you to constantly increase the yield of crops on the same cultivated soils. They very quickly help plants to restore strength, resume growth, bloom and bear fruit abundantly. Therefore, their use is 100% justified.
Mineral fertilizers - food for garden crops, trees, berry bushes, vegetables, root crops in the country. We need to feed the earth in order for it to feed us. And fertilize not only as needed, but always: both in spring and autumn.
Mineral fertilizers - inorganic compounds containing nutrients necessary for plants in the form of various mineral salts. The use of mineral fertilizers is one of the main methods of intensive farming. With the help of fertilizers, you can increase yields. Depending on what nutrients they contain, fertilizers are divided into simple and complex (complex). Simple (one-sided) fertilizers contain any one nutritional element. These include phosphorus, nitrogen, potash and micronutrient fertilizers. Complex (complex), or multilateral, fertilizers contain simultaneously two or more basic nutrients. For the introduction of mineral fertilizers, fertilizer seeders are used. Agrotanks are used to store liquid mineral fertilizers.
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Mineral fertilizers contain nutrients in the form of various mineral salts. Depending on what nutrients are included in them, fertilizers are divided into complex and simple.
Mineral fertilizers are a powerful means of influencing the physical, chemical and biological properties of the soil and the plants themselves. In the soil, mineral fertilizers undergo various transformations that affect the solubility of the nutrients they contain, the ability to move in the soil and the availability of plants. The nature and intensity of these transformations depend on the properties of the soil. Mineral fertilizers enrich the soil with nutrients, change the reaction of the soil solution, affect microbiological processes, etc. Since plant nutrition is carried out mainly through the roots, the introduction of mineral fertilizers into the soil allows you to actively influence the growth and development of plants, and, consequently, the overall biological productivity of a vegetable garden, fields, meadows, etc.
The correct use of mineral fertilizers is the most effective means of increasing the yield of agricultural crops and the quality of products (sugar content of sugar beets, fruits and berries, protein content of grain, oil content of sunflower, etc.)
Almost all mineral fertilizers are produced by the chemical industry (they are obtained by processing agronomic ores or by synthesis), in relatively small quantities in agriculture they use natural salts, for example, potash, sodium (Chilean) nitrate, as well as industrial waste.
For agronomic purposes, direct and indirect fertilizers are distinguished among mineral fertilizers.
Direct mineral fertilizers (contain elements of direct plant nutrition - N, P, K, Mg, B, Cu, Mn, etc.) are subdivided into one-sided and complex fertilizers.
Single-sided mineral fertilizers contain predominantly any one nutrient. These include nitrogen fertilizers (ammonium, sodium, calcium nitrate, ammonium sulfate, urea, etc.), phosphoric (superphosphate, phosphorite flour, precipitate, etc.), potassium (potassium chloride, 30- and 40% potassium salt, potassium sulfate, etc.), micronutrient fertilizers.
Complex fertilizers (double and triple) contain two or more nutrients (nitrophos, ammophos, nitrophoska, etc.)
Indirect mineral fertilizers are used to improve the agrochemical and physicochemical properties of the soil and mobilize its nutrients (for example, lime fertilizers, gypsum). The same fertilizer can have direct and indirect effects. So, the introduction of phosphate rock not only increases the level of phosphorus nutrition of plants, but also weakens the acidity of the soil.
Mineral fertilizers are solid - powder and granular (most of them) - and liquid - ammonia water, liquid ammonia, ammonia.
Depending on the effect on the reaction of the soil solution, physiologically acidic, alkaline and neutral mineral fertilizers are distinguished. Fertilizers are physiologically acidic, the cations of which are better absorbed by the soil than anions, and the latter acidify the soil solution. Fertilizers are physiologically alkaline, the anions of which are better assimilated by plants, and the cations gradually accumulate and alkalinize the soil.
Physiologically neutral mineral fertilizers do not change the reaction of the soil solution.
The efficiency of mineral fertilizers increases in conditions of irrigation and high technology of crop cultivation. Mineral fertilizers in crop rotation are used in a specific system, which is called a fertilization system. It provides for their distribution by areas, rates, timing and methods of application, determined according to the data of agrochemical analysis of the soil and the results of field experiments.
Mineral fertilizers are applied in autumn or spring (main fertilizer), simultaneously with sowing (sowing fertilizer) and during the growing season (plant feeding).
Application methods: scattered with incorporation into the soil with a plow, cultivator or harrow - fertilizers are mixed with the soil of the entire arable layer local - in rows or holes when sowing seeds, planting tubers, seedlings, seedlings.
Mineral fertilizers are also treated with seeds before sowing (dusting, soaking in solution).
Improper use of mineral fertilizers (for example, excessive doses, poor embedding) can reduce soil fertility, cause the death of plants and animals, and pollute rivers and water bodies.
Fertilizer classification, their properties
Classification of existing fertilizers
The enormous importance of fertilizers in increasing soil fertility and crop yields has been proven by numerous experiments of scientific institutions, as well as confirmed by the practice of world agriculture. According to experts, about half of the total increase in crop yields is obtained through the use of fertilizers. The effectiveness of fertilizers in different climatic conditions is not the same and depends on the properties of the soil. Fertilization has a positive effect on all soils under irrigation and in areas with sufficient moisture. Mineral fertilizers, when used correctly, significantly increase yields, as well as improve product quality, as a result of which their use causes a high economic effect.The entire history of world agriculture testifies to the existence of a direct dependence of crop yield on the amount of fertilizers used.
The use of fertilizers is of great importance in solving important national economic problems, for example, in increasing the production of grain and wheat and in providing livestock with fodder. The effectiveness of mineral fertilizers depends on their correct use in combination with organic, methods of chemical reclamation in combination with the use of chemical plant protection agents, as well as growth regulators when growing varieties with high productivity. All of the above conditions for the effective use of fertilizers are taken into account with modern technologies of crop cultivation, one of the most important elements of which is to ensure the optimal nutrition of plants during the growing season with the help of fertilizers. Fertilizers can be classified into mineral and organic fertilizers. Mineral fertilizers, in turn, are subdivided into nitrogen, nitrate, phosphoric, potassium, micronutrient fertilizers. Organic manure includes manure, slurry, bird droppings, peat composts, and green manure.
Mineral fertilizers contain nutrients in the form of various mineral salts. Depending on what nutrients are included in them, fertilizers are divided into complex and simple. Mineral fertilizers are a powerful means of influencing the physical, chemical and biological properties of the soil and the plants themselves. In the soil, mineral fertilizers undergo various transformations that affect the solubility of the nutrients they contain, the ability to move in the soil and the availability of plants. The nature and intensity of these transformations depend on the properties of the soil. Mineral fertilizers enrich the soil with nutrients, change the reaction of the soil solution, affect microbiological processes, etc. Since plant nutrition is carried out mainly through the roots, the introduction of mineral fertilizers into the soil allows you to actively influence the growth and development of plants, and, consequently, the overall biological the productivity of fields, meadows, etc. The correct use of mineral fertilizers is the most effective means of increasing the yield of agricultural crops and the quality of products (technological properties of fiber of spinning crops, sugar content of sugar beets, fruits and berries, protein content of grain, oil content of sunflower, etc.).
The level of supply of mineral fertilizers for 1 hectare of sowing is one of the main indicators of the intensification of agricultural crops in production and its most important industry - agriculture. Almost all mineral fertilizers are produced by the chemical industry (they are obtained by processing agronomic ores or by synthesis), in relatively small quantities in agriculture they use natural salts, for example, potash, sodium (Chilean) nitrate, as well as industrial waste. For agronomic purposes, direct and indirect fertilizers are distinguished among mineral fertilizers. Direct mineral fertilizers (contain elements of direct plant nutrition - N, P, K, Mg, B, Cu, Mn, etc.) are subdivided into one-sided and complex. Single-sided mineral fertilizers contain predominantly any one nutrient. These include nitrogen fertilizers (ammonium, sodium, calcium nitrate, ammonium sulfate, urea, etc.), phosphoric (superphosphate, phosphorite flour, precipitate, etc.), potassium (potassium chloride, 30- and 40% potassium salt, potassium sulfate, etc.), micronutrient fertilizers. Complex fertilizers (double and triple) contain two or more nutrients (nitrophos, ammophos, nitrophoska, etc.). Indirect mineral fertilizers are used to improve the agrochemical and physicochemical properties of the soil and mobilize its nutrients (for example, lime fertilizers, gypsum). The same fertilizer can have direct and indirect effects. So, the introduction of phosphate rock not only increases the level of phosphorus nutrition of plants, but also weakens the acidity of the soil.
Mineral fertilizers are solid - powdery and granular (most of them) - and liquid - ammonia water, liquid ammonia, ammonia. Depending on the effect on the reaction of the soil solution, physiologically acidic, alkaline and neutral mineral fertilizers are distinguished. Fertilizers are physiologically acidic, the cations of which are better absorbed by the soil than anions, and the latter acidify the soil solution. Fertilizers are physiologically alkaline, the anions of which are better assimilated by plants, and the cations gradually accumulate and alkalinize the soil. Physiologically neutral mineral fertilizers do not change the reaction of the soil solution. The efficiency of mineral fertilizers increases in conditions of irrigation and high technology of crop cultivation. Mineral fertilizers in crop rotation are used in a specific system, which is called a fertilization system. It provides for their distribution by fields, rates, timing and methods of application, determined according to the data of agrochemical analysis of the soil and the results of field experiments. Mineral fertilizers are applied in autumn or spring (main fertilizer), simultaneously with sowing (sowing fertilizer) and during the growing season (plant feeding).
Application methods: spreading (fertilizer seeders, from an airplane) with incorporation into the soil with a plow, cultivator or harrow - fertilizers are mixed with the soil of the entire arable layer local - in rows or holes using combined seeders and planters when sowing seeds, planting tubers, seedlings, seedlings ... Mineral fertilizers are also treated with seeds before sowing (dusting, soaking in solution). Improper use of mineral fertilizers (for example, excessive doses, poor embedding) can reduce soil fertility, cause the death of plants and animals, and pollute rivers and water bodies. Nitrogen fertilizers, their classification Nitrogen is one of the main nutrients that are necessary for plant life. Nitrogen plays an extremely important role in metabolism. It is a part of such important organic substances as proteins, nucleic acids, nucleoproteins, chlorophyll, alkaloids, phosphatides, etc. On average, its content in proteins is 16-18% of the mass. Nucleic acids play an important role in the metabolism in plant organisms. They are also carriers of the hereditary properties of living organisms. Therefore, it is difficult to overestimate the role of nitrogen in these vital processes in plants.
In addition, nitrogen is the most important component of chlorophyll, without which the process of photosynthesis cannot proceed and, therefore, organic substances, which are essential for human and animal nutrition, cannot be formed. It is also impossible not to note the great importance of nitrogen as an element that is part of enzymes - catalysts of life processes in plant organisms. Nitrogen is included in organic compounds, including the most important of them - amino acids of proteins. Nitrogen, phosphorus and sulfur, together with carbon, oxygen and hydrogen, are the building blocks for the formation of organic matter and, as a result, living tissue. The nitrogen content in plants varies significantly depending on their type, age, soil and climatic conditions of growing crops, agricultural techniques, etc. For example, in the family of grain crops nitrogen contains 2-3%, in legumes - 4-5%. The highest nitrogen content is observed in the vegetative organs of young plants. As they age, nitrogenous substances move to the newly appeared leaves and shoots. Sources of nitrogen for plants can be salts of nitric and nitrous acids (nitrates, nitrites), ammonia forms of nitrogen, some organic nitrogen compounds - urea and amino acids.
Leguminous plants are known to assimilate atmospheric molecular nitrogen (N2) with the help of nodule bacteria. However, in whatever form mineral nitrogen comes in during plant nutrition, it can take part in the synthesis of amino acids, proteins and other nitrogen-containing organic substances only in the reduced form in the form of ammonium. Therefore, the nitrate nitrogen supplied to plants as a result of the oxidation of carbohydrates is reduced to the anion of nitrous acid, and then to ammonia. The entire complex cycle of synthesis of nitrogenous organic substances in plants begins with ammonia, and their decay ends with its formation. The nitrogen reserve in the soil is to some extent replenished with nitrogen from atmospheric precipitation. It usually comes in the form of ammonia and partly nitrates. These nitrogen compounds are formed in the atmosphere and under the influence of lightning discharges. According to the majority of experts, from 2 to 11 kg of nitrogen is supplied with precipitation per hectare annually. The listed sources of replenishment of natural nitrogen reserves are of undoubted practical interest, but they deliver only a part of nitrogen, which is carried out with crops. Therefore, it is necessary to take measures to optimally increase soil fertility and, above all, replenish the reserves of organic and mineral fertilizers in it. Lack of nitrogen is often a limiting factor in crop growth.
There are numerous pathways for nitrogen loss in nature. The main ones are as follows:
- Immobilization, that is, the consumption of nitrogen by the soil microflora.
- Leaching, primarily of nitrate forms of nitrogen into groundwater.
- Volatilization of ammonia, nitrogen oxides and molecular nitrogen into the air.
- Fixation of ammonium in the soil or its non-exchange absorption.
Nitrates, on the other hand, can accumulate in plants up to a certain limit without harm. In addition, the transition of nitrates to ammonia occurs as it is used for the synthesis of amino acids. No synthesis - no formation of ammonia from nitrates. Nitrates are the best form of plant nutrition at a young age, when the leaf surface is small, as a result of which photosynthesis is still weak in plants and carbohydrates and organic acids are not formed in sufficient quantities. With an increase in the leaf surface, the photosynthesis of carbohydrates increases, the oxidation of which leads to the formation of organic acids, which, in turn, promotes the binding of ammonia by dicarboxylic acids with the formation of amino acids, and then proteins. For crops that contain a sufficient amount of carbohydrates (for example, potato tubers), ammonia and nitrate forms of nitrogen are practically equivalent at the beginning of plant growth. For crops, the seeds of which contain few carbohydrates (for example, sugar beet), nitrate forms of nitrogen have an advantage over ammonia.
The conditions of nitrogen nutrition have a great influence on the growth and development of plants. With a lack of nitrogen, their growth deteriorates sharply. The lack of nitrogen affects the growth of leaves especially strongly: they become smaller, have a light green color, and turn yellow prematurely. The stems become thin and weakly branched. Such plants give a low yield. With normal nitrogen nutrition of plants, the synthesis of protein substances increases, growth is accelerated and leaf aging slows down somewhat. The leaves have an intense green color, the plants form powerful stems, grow and bush well. Excessive nitrogen nutrition during the growing season retards the development of plants, they form a large vegetative mass to the detriment of the reproductive organs. For the development of the leaf surface, the plant needs increased nitrogen nutrition at the beginning of its life. But the excess of ammoniacal nitrogen during germination of seeds, poor in carbohydrates, has a negative effect. Ammonia nitrogen in this case is not fully utilized by the plant, it accumulates in tissues, causing ammonia poisoning.
This does not happen with a nitrate diet. All vegetable crops have high requirements for nitrogen nutrition during the entire growing season. The most intensive increase in cabbage yield is observed in July – August, at which time it absorbs the bulk of nitrogen. Carrots absorb the most nitrogen in late August - early September. The supply of nitrogen to cucumbers increases gradually, reaching a maximum during the period of the greatest growth of ovaries. It has been experimentally proven that only 3-4 weeks after the emergence of seedlings, most vegetable crops use the nutrients of fertilizers applied before sowing to a depth of 20 cm. Lack of nutrition in the initial period of growth, when the root system is still weak and has not penetrated deeply, significantly reduces the subsequent yield ... Therefore, in order to get a high yield of vegetable crops, it is necessary to apply small doses of fertilizers to the rows and holes immediately after sowing seeds and planting seedlings, which ensures normal nutrition at an early age.
The main place in the range of nitrogen fertilizers produced is occupied by concentrated forms of nitrogen: ammonium nitrate, urea, anhydrous ammonia, as well as complex fertilizers, the share of low-percentage fertilizers, such as calcium and sodium nitrate, ammonia water, ammonium sulfate, is constantly decreasing. Nitrogen fertilizers are divided into the following groups: - nitrate fertilizers (nitrate), which contain nitrogen in nitrate form - ammonium and ammonium fertilizers (solid and liquid), which contain nitrogen in ammonium and ammonia form - ammonium-nitrate fertilizers, they contain nitrogen in ammonium and nitrate form (ammonium nitrate) - fertilizers in which nitrogen is in amide form (urea, or urea) - aqueous solutions of urea (urea) and ammonium nitrate, which are called UAN (urea-ammonium nitrate). The production of various nitrogen fertilizers is based on the production of synthetic ammonia from molecular nitrogen and hydrogen. Nitrogen is obtained by passing air into a generator with burning coke, while natural gas, oil and coke gases are used as sources of hydrogen. Synthetic ammonia is used not only for the production of urea, ammonium salts and liquid ammonium fertilizers, but also nitric acid, from which ammonium nitrate fertilizers are obtained.
Nitrate fertilizers - sodium and calcium nitrate - make up about 1% of the produced nitrogen fertilizers. Sodium nitrate (sodium nitrate, Chilean nitrate) contains 16% nitrogen and 26% sodium. It is a by-product in the production of nitric acid from ammonia and is a fine-crystalline white or yellowish-brown salt, readily soluble in water. Possesses weak hygroscopicity. If you store this fertilizer in unsuitable conditions for it, then it can cake. Provides good dispersibility when stored correctly. Calcium nitrate (calcium nitrate) contains about 13% nitrogen. It is obtained by neutralizing nitric acid with lime, and also as a by-product in the production of complex fertilizers - nitrophos - by nitric acid processing of phosphates. Calcium nitrate is a white crystalline salt, readily soluble in water. Highly hygroscopic. Under improper storage conditions (for example, with high humidity in the room), it becomes very damp, cakes and spreads. It is stored and transported in special waterproof packaging.
To reduce hygroscopicity, calcium nitrate is granulated using hydrophobic coatings. Calcium and sodium nitrate are physiologically alkaline fertilizers. Plants consume more anions than cations.The use of calcium nitrate on acidic, poor in bases soils gives good results. When applied, acidity decreases, and the physical properties of the soil are improved. In humid climates or with abundant irrigation, nitrate nitrogen can be washed out of the soil, and also lost in the form of gaseous products during denitrification. It is not recommended to apply saltpeter in the fall, it is better to close them up in the spring for pre-sowing cultivation. These fertilizers can be used as top dressing for winter and row crops, and sodium nitrate - when sowing sugar beets, fodder and table root crops in rows. The effectiveness of sodium nitrate is related to the role of sodium.
It enhances the outflow of carbohydrates from the leaves, resulting in an increase in the yield of root crops and their sugar content. Ammonium and ammonium fertilizers Solid ammonium fertilizers account for approximately 4% of the gross production of nitrogen fertilizers. The production of solid fertilizers is constantly increasing. Solid ammonium fertilizers include ammonium sulfate and ammonium chloride. Ammonium sulfate contains approximately 21% nitrogen. Ammonium sulfate is a crystalline salt that is highly soluble in water. The hygroscopicity of the fertilizer is weak, under normal storage conditions it cakes little and retains good spreading ability. Ammonium sulfate is obtained by capturing ammonia with sulfuric acid from gases that are formed during coking of coal, or by neutralizing spent sulfuric acid from various chemical industries with synthetic ammonia. A large amount of ammonium sulfate is produced as a by-product in the production of caprolactam. Synthetic ammonium sulfate is white, and coke-chemical has a gray, bluish or reddish color. The fertilizer contains 24% sulfur and is a good source of this nutrient for plants.
Ammonium chloride is a byproduct of soda production. The fertilizer contains about 25% nitrogen. It is of little use for crops, as it contains a large amount of chlorine. Ammonium sulfate and ammonium chloride are physiologically acidic fertilizers. With a single application of moderate doses of these fertilizers, soil acidification is not observed, but if they are used constantly, then low-buffer soils are significantly acidified. After application to the soil, ammonium fertilizers quickly dissolve in soil moisture and enter into exchange reactions with cations. Absorbed ammonium is readily available to plants. Its mobility in the soil and the risk of leaching under normal moisture conditions are reduced. Ammonium fertilizers are best applied using special machines in autumn for plowing.
For feeding, it is better to use nitrate fertilizers, ammonium fertilizers are used before sowing as the main fertilizer. Over time, the difference in the mobility of nitrate and ammonium fertilizers smoothes out, since ammonium nitrogen is gradually nitrified and converted into the nitrate form. Ammonium chloride is nitrified more slowly than ammonium sulfate, which is due to the negative effect of chlorine on the activity of nitrifying bacteria. With the constant use of ammonium fertilizers, especially on low-buffered and poorly cultivated sod-podzolic soils, the active, exchangeable and hydrolytic acidity increases, the degree of soil saturation with bases decreases, and the content of mobile forms of aluminum and manganese increases. As a result, the conditions for plant growth deteriorate and the effectiveness of fertilizers decreases. The need for liming is increasing. Crops sensitive to soil acidity, such as wheat, barley, cabbage, and beets, strongly react to the acidifying effect of ammonium fertilizers. For these plants, ammonium fertilizers from the first years of their use are less effective than nitrate fertilizers.
A good filling of the soil with manure, which increases its buffering capacity, also reduces the negative effect of these fertilizers on soil properties and is of great importance for their more efficient use. Liquid ammonia fertilizers include anhydrous ammonia and ammonia water. Anhydrous ammonia contains 82% nitrogen. It is obtained by liquefying gaseous ammonia under pressure. In appearance, a colorless, mobile liquid, boiling point 20 ° C. Evaporates quickly when stored in open containers. Anhydrous ammonia has a high vapor pressure, so it is stored and transported in steel cylinders or tanks that can withstand high pressure. Ammonia water is an aqueous 25% and 22% ammonia solution produced in two grades with a nitrogen content of 20, 5% and 18%. The solution is a colorless or yellowish liquid with a pungent ammonia odor. The vapor pressure is low. It is necessary to transport and store ammonia water in hermetically sealed tanks, which are designed for low pressure. The advantage of liquid nitrogen fertilizers is that their production and use are much cheaper than solid ones.
In the production of liquid ammonium fertilizers, there is no need for the construction of nitric acid shops, as well as crystallization, evaporation, granulation, drying, which can significantly reduce capital investments for the construction of a nitrogen fertilizer plant of equivalent capacity. When used correctly, liquid nitrogen fertilizers give the same increase in crop yields as an equal dose of nitrogen in ammonium nitrate. Liquid ammonia fertilizers are applied by special machines that ensure their immediate incorporation to a depth of 12 cm on heavy soils and up to 18 cm on light soils. Surface application of these fertilizers is unacceptable, as the ammonia evaporates quickly. With shallow incorporation, significant losses are possible, especially on light sandy and sandy loam soils. The loss of ammonia from wet soil is much less than from dry soil. When applying liquid ammonia fertilizers, the ammonium ion is absorbed and therefore weakly moves in the soil. In the first days after the incorporation of fertilizers, the soil is alkalized, and then, as ammonia nitrogen nitrifies, its reaction shifts towards acidification. With nitrogen nitrification of fertilizers, its mobility in the soil increases. In the zone of anhydrous ammonia application, the soil is temporarily sterilized, and the rate of nitrification slows down. Liquid ammonium fertilizers can be used for the main application for all crops, not only for presowing cultivation, but also in autumn for plowing. They can also be used for feeding tilled crops. In this case, in order to avoid plant burns, fertilizers are embedded in the middle of the rows or at a distance of at least 12 cm from the plants. When working with liquid ammonium fertilizers, you should follow the safety rules, since ammonia vapors irritate the mucous membranes of the eyes and respiratory tract, choking and coughing. When inspecting and repairing containers for these fertilizers, you must take precautions, since the mixture of ammonia with air is explosive.
Ammonium nitrate fertilizers
Ammonium nitrate is the main nitrogen fertilizer, which contains 34% nitrogen. Fertilizer is produced in the form of white crystals or granules up to 3 mm in size of various shapes (spherical, in the form of scales, plates). Non-granular crystalline ammonium nitrate is highly hygroscopic, cakes during storage, so it must be stored in waterproof bags in a dry room. Granular nitrate produced for agriculture is less hygroscopic, less caking, retains good dispersibility, especially if special conditioning additives are introduced into it in small quantities in the process of obtaining fertilizer. Ammonium nitrate is a highly soluble, highly concentrated universal fertilizer. It can be used for any crops and on all soils before sowing, when sowing in rows or holes, and as a top dressing. In fertilizers, half of the nitrogen is in the nitrate form, and half in the ammonium form. Ammonium nitrate is a physiologically acidic fertilizer, but acidifies the soil less than ammonium sulfate. On soils saturated with bases, calcium nitrates are formed in the solution, and the soil solution does not acidify even with constant application of high doses of fertilizer. For such soils, ammonium nitrate is one of the best forms of nitrogen fertilizers. On acidic soddy-podzolic soils, containing little calcium and many hydrogen ions in an absorbed state, as a result of which the soil solution is acidified, acidification is temporary, since it disappears as the plants consume nitrate nitrogen. At first, especially when a large dose of ammonium nitrate is applied and its uneven sieving, foci with high acidity can be created in the soil. With prolonged use of ammonium nitrate on low-buffer sod-podzolic soils, acidification can be very strong, as a result, the effectiveness of this fertilizer, especially when applied under crops sensitive to high acidity, is noticeably reduced. To increase the efficiency of ammonium nitrate on acidic soils, their liming is of great importance. On acidic soddy-podzolic soils, neutralized, or lime, ammonium nitrate gives a higher effect, especially with constant use. It contains up to 23% nitrogen and is obtained by fusing or mixing ammonium nitrate with an equivalent amount of lime, chalk or dolomite.
Urea (carbamide) contains at least 46% nitrogen. It is obtained by synthesis from ammonia and carbon dioxide at high pressures and temperatures. White, fine-crystalline product, readily soluble in water. The hygroscopicity is low at temperatures up to 20 ° C. Under good storage conditions, there is little caking, maintains normal spreading properties. Granular urea has good physical characteristics. During the granulation of urea, biuret is formed, which has a toxic effect, however, its content in the granular fertilizer does not exceed 1% and is almost harmless to plants in normal use. In the soil, under the influence of urobacteria, which secrete the enzyme urease, urea is ammonified for 2-3 days with the formation of ammonium carbonate. In the first days after the introduction of urea, due to the formation of a hydrolytic alkaline salt, a temporary local alkalinization of the soil occurs. The resulting alkaline salt is absorbed by the soil and gradually nitrified, and nitrification proceeds faster, and the temporary alkalization of the soil is replaced by some acidification. On poorly buffered light soils, displacements in the reaction of the soil solution can be especially noticeable.
Urea is one of the best nitrogen fertilizers and is equivalent in efficiency to ammonium nitrate. It can be used as a basic fertilizer or as a top dressing for all crops and on various soils. When urea is introduced into the soil, it is necessary to seal it up in advance, since when the fertilizer is placed on the surface, nitrogen losses are possible due to the volatilization of ammonia from ammonium carbonate, which is easily decomposed in the air. Significant losses in the form of ammonia can occur when using urea for fertilizing in meadows and pastures, since the sod has a high urease activity. In addition, urea can be used for foliar feeding of vegetable and fruit crops, as well as for late feeding of wheat in order to increase the protein content in the grain. Unlike other nitrogen fertilizers, urea, even in high concentrations, does not burn the leaves and, at the same time, is well absorbed by plants.
Also, urea is used in animal husbandry as a nitrogen supplement to carbohydrate feed. Aqueous solutions of ammonium nitrate and urea Ammonia and UAN are used as liquid nitrogen mixtures. Ammoniases are called solutions obtained by joint or separate dissolution in ammonia water of specified amounts of ammonium or calcium nitrate, carbamide or other nitrogen-containing substances. UAN is called liquid nitrogen fertilizers, consisting of aqueous solutions of urea and ammonium nitrate. Unlike liquid ammonia fertilizers, UAN contains almost no free ammonia; it can be applied using high-performance ground-based implements without simultaneous incorporation into the soil. UAN with a corrosion inhibitor can be transported in conventional rail tank cars and tank trucks; transportation of UAN through pipelines and water transport is especially advantageous. The low crystallization and freezing temperature makes it possible to transport and store UAN year-round, especially in naturally insulated storage facilities buried in the soil, made of concrete and asphalt with an inner film coating, reinforced fiberglass or mild steel.
UAN has a high density, which can significantly reduce capital investments for transportation and storage. When using UAN, high dosing accuracy and uniformity of application over the entire area are ensured. For transportation and application of UAN, you can use the same technique as for liquid complex fertilizers, ammonia water. The use of UAN in agriculture has its advantages over solid fertilizers.
First, full mechanization of all loading and unloading operations, reducing production and application costs.
Secondly, working conditions are improved, container consumption is eliminated, and the uniformity of nitrogen application and dosage is ensured.
Thirdly, it simplifies the preparation of the necessary fertilizer mixtures, including those with the addition of trace elements and pesticides.
Liquid nitrogen fertilizers do not have the disadvantages that are often seen in solid fertilizers. They have free fluidity, do not generate dust and do not cake. Damp weather and even rain do not negatively affect them. They are also much cheaper than solid ones, and the labor costs for their introduction are less. Liquid nitrogen fertilizers are applied to the soil by trailed or mounted machines in an aggregate with plows or cultivators to a certain depth (to avoid ammonia losses): ammonia water and ammonia - by 10-12 cm, liquid anhydrous ammonia - by 15-20 cm (depending on mechanical composition of the soil). Liquid fertilizers can be used not only in spring, but also at the end of summer (for sowing winter crops) and in autumn (for the next spring crop). Solutions of ammonium nitrate and urea (up to 30–32%) do not contain ammonia, so they can be applied as a top dressing by sprinkling on the soil surface. Doses of liquid fertilizers (nitrogen) are the same as for solid nitrogen fertilizers.
Complex liquid fertilizers are aqueous solutions containing up to 27% nitrogen, phosphorus and potassium. With the introduction of stabilizing additives, for example, colloidal clay, bentonite, which protect the solution from crystallization, the concentration of nutrients in the fertilizer can be increased up to 40%. Complex liquid fertilizers do not contain free ammonia, so they can be applied superficially for plowing, cultivation or harrowing and in rows when sowing. From the point of view of consumer properties, the use of solutions (suspensions) makes it possible to completely mechanize the laborious processes of loading and unloading fertilizers, and their introduction into the soil. Improving the efficiency of nitrogen fertilizers Until recently, it was believed that plants use up to 80% of the nitrogen fertilizer. The coefficient of nitrogen utilization by plants was determined by the difference method (according to the difference in nitrogen removal with the crop with and without nitrogen application) and was expressed as a percentage of the applied amount of fertilizer.The use of the tagged atom method in agrochemical studies made it possible to establish that in field conditions, plants assimilate only 30–50% of nitrogen directly from fertilizers.
However, when nitrogen fertilizers are applied, the mineralization of soil nitrogen and its assimilation by plants increase. Nitrogen utilization rates for different forms of nitrogen fertilizers do not differ significantly. The conversion of nitrogen into organic form increases sharply when organic matter with a low nitrogen content is plowed into the soil. Fixed nitrogen is slowly mineralized and poorly absorbed by plants. Losses of nitrogen during the denitrification of nitrates formed during the nitrification of ammonium nitrogen of the soil and ammonium nitrogen fertilizers and urea, as well as from nitrate nitrogen fertilizers, are very significant. Losses of fertilizer nitrogen increase sharply in steaming soil and reach 50%. The most intense gaseous nitrogen losses during biological and indirect denitrification occur in the first 20 days after the application of nitrogen fertilizers and under conditions of limited biological absorption in the soil. With increasing doses of nitrogen fertilizers, losses increase.
Losses of nitrogen in fertilizers due to leaching of nitrates on cohesive soils are insignificant, and on light drained soils with a leaching mode of moistening can be significant. Large losses due to the volatilization of ammonia are observed when the technology of applying ammonia forms of liquid nitrogen fertilizers is violated, as well as during surface application and untimely incorporation of urea on carbonate and alkaline soils. An increase in the efficiency of nitrogen in fertilizers and a decrease in losses are provided with an increase in the amount of nitrogen assimilation by agricultural crops by optimizing the regime and conditions of plant nutrition, as well as agrotechnical measures and creating a favorable water regime and soil reaction. Under the influence of nitrogen fertilizers, the mineralization of organic matter increases and not only the assimilation of soil nitrogen by plants increases, but also its loss.
Losses of nitrogen in fertilizers can be reduced by enhancing the immobilization or inhibition of mineralization of soil organic matter by applying organic fertilizers, including straw, carrying out agrotechnical soil protection and nature conservation measures, growing stubble crops and catch crops, cultivating grasses, and using green fertilizers. To avoid nitrogen losses and eliminate the risk of nitrate pollution in plants and the environment,
Potassium has a beneficial effect on increasing yields and increasing plant resistance to diseases. Also, the keeping period of fruits increases and their taste improves.
Usually potash fertilizers are not used in their pure form, but combined with nitrogen, phosphorus and trace elements (copper, zinc, iron, magnesium, etc.). This type of fertilizer is highly soluble in water.
The main types of potash fertilizers:
Potassium chloride - natural fertilizer for the garden, obtained from potash ore. It also contains chlorine, undesirable for a number of plants. Due to this combination, potassium chloride is introduced into the ground in the fall and washed off in the spring. Potassium is good for potatoes, beets, buckwheat and a number of other grains. Application rate per 1 sq. m is 15-20 g.
Potassium salt - fertilizer with potassium chloride, sylvinite and kainite. It is an analogue of potassium chloride and is introduced into the ground in the fall. Potassium salt application rates 12-25 g per sq. m.
Potassium sulfate - due to the absence of chlorine in the composition, it is extremely useful for all plants and for root crops in particular. This fertilizer can be applied directly to the soil or top dressing. It goes well with calcium-free micro and macro fertilizers. The application rate is different for different crops.
The calculation of the rate of application of mineral dressings is made for large areas planted with one type of plants. However, if you correctly calculate the ratio of the components included in them, you can successfully apply mineral fertilizers even in a small summer cottage. Reference books indicate the norms for each of the groups of fertilizers (nitrogen, magnesium, potash, etc.). Here are some of the dosages:
1. Nitrogen-containing preparations:
- saltpeter - up to 25 g / m2
- urea - up to 20 g / m2
- ammonium sulfate - up to 40 g / m2.
2. Phosphorus-containing mineral fertilizers:
- superphosphate - up to 60 g / m2
- double superphosphate - 1.5 times less than the previous one
- phosphate rock. Cannot be used with lime!
- potassium sulfate - up to 25 g / m2
- potassium-magnesium preparation - up to 25 g / m2
- potash. Apply only on acidic soil under potatoes!
Dolomite flour can be used as a magnesium fertilizer for acidic soils. Its application rate is up to 300 g / m2.
Complex fertilizers are applied in the following dosage:
- ammophos - up to 30 g / m2
- nitrophoska - up to 80 g / m2
- diammophos - up to 30 g / m2
- nitroammophoska - up to 80 g / m2.
In each case, before applying mineral fertilizer, it is recommended to check the reaction of the soil to the composition using a litmus test. If it turns blue, the soil is alkaline, if it turns red, it is acidic. Competent dosing with an integrated approach will give excellent results.
Mineral fertilizers are industrial or fossil products containing nutrients in the form of salts, usually mineral, but sometimes organic (urea). [four]
According to the content of nutrients, one-component (one-component) fertilizers are distinguished, containing only one main nutrient (nitrogen, phosphorus, potassium, magnesium, boron, etc.).
According to their state of aggregation, they are solid, liquid or suspended.
By structure - powdery, crystalline, granular.
- ammonia - fertilizers containing nitrogen in the form of an ammonia group
- nitrate - fertilizers containing nitrogen in the form of a nitrate group
- ammonia-nitrate - fertilizers containing nitrogen in both nitrate and ammonia form at the same time
- amide - fertilizers containing nitrogen in the amide form of an organic urea compound (urea or carbamide)
- liquid nitrogen fertilizers - fertilizers containing nitrogen and in a liquid state of aggregation (ammonia water, anhydrous ammonia, UAN). (Photo)
Until the beginning of the last century, the supply of nitrogen fertilizers to the world market was due to the natural deposits of Chilean nitrate on the coast of South America, as well as due to the ammonia of the waste gases of the coke ovens of the metallurgical industry. However, these sources were limited and could not meet the growing demand for nitrogen fertilizers. 
Modern production of various nitrogen fertilizers is based on the formation of synthetic ammonia from molecular nitrogen and air. [four]
Classification scheme for the main types of fertilizers
- Containing phosphorus in a water-soluble form - phosphorus is readily available to plants. This group includes simple superphosphate, double superphosphate, superphos.
- Containing phosphorus, insoluble in water, but soluble in weak acids (2% citric acid) - phosphorus of these fertilizers is available to plants to a somewhat lesser extent. This group of fertilizers includes precipitate, tomoslag, open-hearth phosphate slag, defluorinated phosphate.
- Containing phosphorus, insoluble in water, poorly soluble in weak acids and completely soluble in strong acids (sulfuric, nitric) - the phosphorus of these fertilizers is difficult to access for most plants. This group includes phosphate rock, bone meal. 
Phosphorus does not have natural sources of replenishment in the soil like nitrogen, but the natural reserves of phosphorus in the soil are quite significant. However, most of the soil phosphorus compounds are difficult for plants to access. In addition, agricultural crops carry out the removal of some of the phosphorus with the harvest, which necessitates the use of phosphorus fertilizers. 
The raw materials for the production of phosphorus fertilizers are apatites and phosphorites - natural phosphorus-containing ores, and metallurgical waste. 
Raw potassium salts
Concentrated potash fertilizers
The provision of arable soils with potassium in Russia is better than phosphorus. However, more than a third of the areas have a low and medium level of its content and require the introduction of potash fertilizers. 
Complex fertilizers, depending on the amount of nutrient components, are double and triple. By production methods - complex, complex-mixed and mixed. By the form of release - liquid, suspended, granular.
All technologies for obtaining complex fertilizers are reduced to nitric acid decomposition of phosphate raw materials or the use of phosphoric acids.
Complex fertilizers are highly soluble and highly effective on all types of soils. [one]
- Boron fertilizers (boric acid, borosuperphosphate, boron-magnesium fertilizers, sodium salt (borax)). Boric fertilizers are needed for sod-gley and dark-colored boggy soils, as well as limed sod-podzolic, saturated with bases, sandy and sandy loam soils. [four]
- Molybdenum fertilizers (ammonium molybdate). The maximum effect is shown by the use of molybdenum for grain legumes and vegetables, perennial and annual legumes in meadows and pastures with the presence of legumes in herbage on acid soddy-podzolic, gray forest soils and leached chernozems. [four]
- Manganese fertilizers (manganese sulfate pentahydrate). Plants on sandy, sandy loam soils and carbonate peatlands especially need this element. [four]
- Copper fertilizers (pyrite cinders, copper sulfate). Cultures on newly developed low-lying peatlands and waterlogged soils with a neutral or alkaline reaction, as well as sod-gley soils, especially suffer from a lack of copper. [four]
- Zinc fertilizers (zinc sulfate). Zinc deficiency most often affects fruit and citrus crops on calcareous soils with a neutral and slightly alkaline reaction. [four]
Trace elements are necessary for plants in small quantities. Moreover, each of them performs strictly defined functions in metabolism, plant nutrition and cannot be replaced by another element. [four]