The French name for the element (azote), which stuck in Russian, was proposed in the 18th century. Lavoisier, having formed it from the Greek negative prefix "a" and the word "zoe" - life (the same root in the words zoology and the mass of its derivatives - zoo, zoogeography, etc.), i.e. Nitrogen means lifeless, lifeless. The German name for this element, Stickstoff, is of the same origin - a suffocating substance. The root "azo" is also present in the chemical terms "azide", "azo compound", "azine", etc. And the Latin nitrogenium and English nitrogen come from the Hebrew "neter" (Greek "nitron", Latin nitrum); so in ancient times they called natural alkali - soda, and later - saltpeter. The name "nitrogen" is not entirely apt: although gaseous nitrogen is not suitable for breathing, this element is absolutely necessary for life. The composition of all living things includes a relatively small number of elements, and one of the most important of them is nitrogen, in proteins - about 17% nitrogen. Nitrogen is also included in the composition of DNA and RNA molecules, which provide heredity.
There is a lot of nitrogen on Earth, but its main reserves are concentrated in the atmosphere. However, due to the high strength of the triple bond NєN (942 kJ / mol, which is almost 4 times the energy of the Cl – Cl bond), the nitrogen molecule is very strong, and its reactivity is low. As a result, no animal or plant is able to assimilate nitrogen gas from the air. Where do they get this element, which they need for the synthesis of proteins and other essential components of the body? Animals get nitrogen by eating plants and other animals. Plants extract nitrogen along with other nutrients from the soil, and only a few legumes can absorb nitrogen from the air - and then not on their own, but thanks to the nodule bacteria living on their roots.
The main source of nitrogen in the soil is biological nitrogen fixation, that is, the binding of atmospheric nitrogen and its conversion by microorganisms into forms assimilable by plants. Microorganisms can live in the soil by themselves, or they can be in symbiosis ("commonwealth") with some plants, mainly with legumes - clover, peas, beans, alfalfa, etc. Bacteria "settle" on the roots of these plants - in special nodules; they are often called nodule bacteria. These microorganisms contain a complex enzyme called nitrogenase, which is capable of reducing nitrogen to ammonia. Then, with the help of other enzyme systems, ammonia is converted into other nitrogen compounds, which are assimilated by plants. Free-living bacteria bind up to 50 kg of nitrogen per year per 1 ha, and nodule bacteria - another 150 kg, and in especially favorable conditions - up to 500 kg!
The second source of natural nitrogen in soil is lightning. Every second, an average of 100 lightning flashes on the globe. And although each of them lasts only a fraction of a second, their total electrical capacity reaches 4 billion kilowatts. A sharp increase in temperature in the lightning channel - up to 20,000 ° С leads to the destruction of nitrogen and oxygen molecules with the formation of nitrogen oxide NO. Then it is oxidized by atmospheric oxygen into dioxide: 2NO + O 2 2NO 2. Dioxide, reacting with an excess of oxygen with atmospheric moisture, turns into nitric acid: 4NO 2 + 2H 2 O + O 2 4HNO 3. As a result of these transformations, about 2 million tons of nitric acid or more than 700 million tons per year are formed in the atmosphere. A weak solution of nitric acid falls to the ground with rain. It is interesting to compare this amount of "celestial acid" with its industrial production; production of nitric acid is one of the largest production facilities. It turns out that here man lags far behind nature: the world production of nitric acid is about 30 million tons. Due to the splitting of nitrogen molecules by lightning, about 15 kg of nitric acid falls annually for every hectare of the earth's surface, including mountains and deserts, seas and oceans. In the soil, this acid passes into its salts - nitrates, which are perfectly absorbed by plants.
It would seem that "thunderstorm nitrogen" is not so important for crops, but clover and other legumes cover only a small part of the earth's surface. Lightning began to flash in the atmosphere billions of years ago, long before the appearance of nitrogen-fixing bacteria. So they played a prominent role in the binding of atmospheric nitrogen. For example, in the last two millennia alone, lightning has transferred 2 trillion tons of nitrogen into fertilizers - approximately 0.1% of its total amount in the air!
Liebig vs. Malthus... In 1798, the English economist Thomas Malthus (1766-1834) published his famous book Population experience... In it, he pointed out that the population tends to grow exponentially, i.e. like 1, 2, 4, 8, 16 ... At the same time, livelihoods for the same periods of time, even in the most favorable conditions, can grow only in an arithmetic progression, i.e. like 1, 2, 3, 4 ... For example, according to this theory, food production can only grow by expanding agricultural land, better cultivating arable land, etc. From the theory of Malthus it followed that in the future, humanity is threatened with hunger. In 1887 this conclusion was confirmed by the English scientist Thomas Huxley (1825–1897), a friend of Charles Darwin and popularizer of his teachings.
To avoid the "starvation" of mankind, it was necessary to dramatically increase the productivity of agriculture, and for this it was necessary to solve the most important issue of plant nutrition. Probably, the first experiment in this direction was carried out in the early 1630s by one of the greatest scientists of his time, the Dutch physician and alchemist Jan Baptiste van Helmont (1579-1644). He decided to check whether the plants get their nutrients from water or from soil. Van Helmont took 200 pounds (approx. 80 kg) of dry soil, poured it into a large pot, planted a willow branch in the ground, and diligently sprinkled it with rainwater. The branch took root and began to grow, gradually turning into a tree. This experience lasted exactly five years. It turned out that during this time the plant gained 164 pounds 3 ounces (about 66 kg), while the earth "lost weight" by only 3 ounces, ie. less than 100 g. Consequently, Van Helmont concluded, plants take nutrients only from water.
Subsequent studies seem to have refuted this conclusion: after all, there is no carbon in water, which makes up the bulk of plants! From this it followed that plants literally "feed on air", absorbing carbon dioxide from it - the same gas that Van Helmont discovered and even called it "forest air." This name was given to the gas not at all because there is a lot of it in the forests, but only because it is formed when charcoal burns ...
The question of "air nutrition" of plants was developed at the end of the 18th century. Swiss botanist and physiologist Jean Senebier (1742-1809). He experimentally proved that carbon dioxide decomposes in the leaves of plants, while oxygen is released, and carbon remains in the plant. But some scientists strongly objected to this point of view, defending the "humus theory" according to which plants feed mainly on organic matter extracted from the soil. This seemed to be confirmed by the centuries-old practice of farming: the soil, rich in humus, well fertilized with manure, gave increased yields ...
However, the humus theory did not take into account the role of minerals, which are absolutely necessary for plants. Plants extract these substances from the soil in large quantities, and during harvesting they are carried away from the fields. For the first time, the German chemist Justus Liebig pointed out this circumstance, as well as the need to return mineral substances to the soil. In 1840 he published the book Organic chemistry as applied to agriculture and physiology, in which, in particular, he wrote: "The time will come when each field, in accordance with the plant that will be cultivated on it, will be fertilized with the proper fertilizer prepared in chemical factories."
At first, Liebig's ideas were met with hostility. "This is the most shameless book of all that ever fell into my hands," - wrote about her professor of botany at the University of Tübingen Hugo Mohl (1805-1872). "A completely meaningless book," - echoed the famous German writer Fritz Reiter (1810-1874), who was engaged in agriculture for some time. German newspapers began to publish offensive letters and cartoons of Liebig and his theory of the mineral nutrition of plants. Liebig himself was partly to blame for this, who at first mistakenly believed that mineral fertilizers should contain only potassium and phosphorus, while the third necessary component - nitrogen - plants themselves can assimilate from the air.
Liebig's mistake was probably due to a misinterpretation of the experiments of the famous French agrochemist Jean Baptiste Boussingault (1802–1887). In 1838, he planted the suspended seeds of some plants in soil that did not contain nitrogen fertilizers, and after 3 months he weighed the shoots. In wheat and oats, the weight practically did not change, while in clover and peas it increased significantly (in peas, for example, from 47 to 100 mg). From this, it was incorrectly concluded that some plants can assimilate nitrogen directly from the air. At that time, nothing was known about the nodule bacteria living on the roots of legumes and capturing atmospheric nitrogen. As a result, the first attempts to apply only potash-phosphorus fertilizers everywhere yielded negative results. Liebig had the courage to openly admit his mistake. His theory won out in the end. The result was the introduction to agriculture in the second half of the 19th century. chemical fertilizers and construction of plants for their production.
Nitrogen crisis.
There were no particular problems with phosphorus and potash fertilizers: in the bowels of the earth, compounds of potassium and phosphorus are found in abundance. The situation was completely different with nitrogen: with the intensification of agriculture, which was supposed to feed the rapidly growing population of the Earth, natural sources ceased to cope with the replenishment of nitrogen reserves in the soil. There is an urgent need to find sources of "bound" nitrogen. Chemists were able to synthesize some compounds, for example, lithium nitride Li 3 N, starting from atmospheric nitrogen. But in this way it was possible to get grams, at best - kilograms of matter, while millions of tons were required!
For centuries, practically the only source of bound nitrogen has been saltpeter. This word comes from the Latin sal - salt and nitrum, literally - "alkaline salt": at that time the composition of the substances was unknown. Currently, some nitric acid salts - nitrates are called nitrate. Several dramatic milestones in human history are associated with saltpeter. Since ancient times, only the so-called Indian saltpeter has been known - potassium nitrate KNO 3. This rare mineral was brought from India, while in Europe there were no natural sources of saltpeter. Indian nitrate was used exclusively for the production of gunpowder. Every century more and more gunpowder was required, but there was not enough imported saltpeter, and it was very expensive.
Over time, they learned to get saltpeter in special "saltpeter" from various organic residues that contain nitrogen. Quite a lot of nitrogen, for example, in proteins. If the solids are simply incinerated, the nitrogen contained in them will mainly oxidize to gaseous N 2. But if they undergo rotting, then under the action of nitrifying bacteria, nitrogen is converted into nitrates, which were leached in the old days in special heaps - piles, and saltpeter was called burtovaya. They did it this way. They mixed various organic waste - manure, animal entrails, silt, swamp slurry, etc. Garbage, lime, ash were also added there. This terrible mixture was poured into pits or made heaps of it and poured abundantly with urine or slurry. You can imagine what a smell came from this production! Due to the decomposition processes within one to two years from 6 kg of "saltpeter earth" received 1 kg of saltpeter, which was purified from impurities. Most of all saltpeter was received in France: the government generously rewarded those who were engaged in this unpleasant production.
Thanks to the efforts of Liebig, it became obvious that saltpeter would be needed for agriculture, and in much larger quantities than for the production of gunpowder. The old way of obtaining it was completely unsuitable for this.
Chilean saltpeter.
Since 1830, the development of Chilean saltpeter deposits, the richest natural source of nitrogen, began. Chile has huge areas that never rain, for example, the Atacama Desert, located in the foothills of the Cordillera at an altitude of about 1000 m above sea level. As a result of millennial processes of decomposition of plant and animal organic residues (mainly bird droppings - guano), unique deposits of saltpeter were formed in Atacama. They are located 40-50 km from the ocean coast. When these deposits began to be developed, they stretched in a strip about 200 km long and 3 km wide with a stratum thickness of 30 cm to 3 m. In the basins, the strata thickened significantly and resembled dried up lakes. As analyzes have shown, Chilean nitrate is sodium nitrate with admixtures of sodium sulfate and chloride, clay and sand; sometimes undecomposed guano remains are found in saltpeter. An interesting feature of Chilean nitrate is the presence of sodium iodate NaIO 3 in it.
Usually the rock was soft and easy to extract from the ground, but sometimes the saltpeter deposits were so dense that blasting was required to extract them. After dissolving the rock in hot water, the solution was filtered and cooled. At the same time, pure sodium nitrate precipitated out, which was sold as fertilizer. Iodine was extracted from the remaining solution. In the 19th century. Chile has become a major supplier of saltpeter. The development of deposits ranked first in the mining industry of Chile in the 19th century.
To obtain potassium nitrate from Chilean nitrate, the reaction NaNO 3 + KCl ® NaCl + KNO 3 was used. This reaction is possible due to the sharp difference in the solubility of its products at different temperatures. The solubility of NaCl (in grams per 100 g of water) changes only from 39.8 g at 100 ° C to 35.7 g at 0 ° C, while the solubility of KNO 3 at the same temperatures differs very strongly and amounts to 246 and 13.3 G! Therefore, if you mix hot concentrated solutions of NaNO 3 and KCl, and then cool the mixture, then a significant part of KNO 3 will precipitate, and almost all of the NaCl will remain in solution.
For decades, Chilean nitrate, a natural sodium nitrate, has satisfied human needs. But as soon as the unique value of this mineral for world agriculture was revealed, they began to calculate how long this unique gift of nature would last for mankind. The first calculations were quite optimistic - in 1885 the stock of nitrate was determined at 90 million tons. It turned out that one need not worry about the "nitrogen starvation" of plants for many more years. But these calculations did not take into account the rapid population growth and rates of agricultural production around the world.
During the time of Malthus, the export of Chilean nitrate was only 1000 tons per year; in 1887 it reached 500 thousand tons per year, and at the beginning of the 20th century. already calculated in millions of tons! Chilean nitrate stocks were rapidly depleted, while the demand for nitrates grew extremely rapidly. The situation was aggravated by the fact that the military industry also consumed large quantities of saltpeter; gunpowder of the late 19th century contained 74–75% potassium nitrate. It was necessary to develop new methods for obtaining nitrogen fertilizers, and their source could only be atmospheric air.
Overcoming the "nitrogen hunger".
At the beginning of the 20th century. the cyanamide method has been proposed for industrial nitrogen fixation. First, by heating a mixture of lime and coal, calcium carbide was obtained: CaO + 3C ® CaC 2 + CO. At high temperatures, carbide reacts with nitrogen in the air to form calcium cyanamide: CaC 2 + N 2 ® CaCN 2 + C. This compound turned out to be suitable as a fertilizer not for all crops, therefore, ammonia was first obtained from it by the action of superheated steam: CaCN 2 + 3H 2 O ® CaCO 3 + 2NH 3, and ammonium sulfate was already obtained from ammonia and sulfuric acid.
Norwegian chemists chose a completely different way, using cheap local electricity (there are many hydroelectric power plants in Norway). They actually mimicked the natural process of nitrogen fixation by passing humid air through an electric arc. At the same time, about 1% of nitric acid was obtained from the air, which, by interaction with lime, was converted into calcium nitrate Ca (NO 3) 2. Not surprisingly, this substance was called Norwegian nitrate.
However, both methods were too expensive. The most economical method for fixing nitrogen was developed in 1907-1909 by the German chemist Fritz Haber (1868-1934); this method converts nitrogen directly to ammonia; converting ammonia into nitrates and other nitrogen compounds was no longer difficult.
At present, the production of nitrogen fertilizers is estimated at tens of millions of tons per year. They come in different types depending on their chemical composition. Ammonium and ammonium fertilizers contain nitrogen in the oxidation state –3. This is liquid ammonia, its aqueous solution (ammonia water), ammonium sulfate. NH 4 + ions under the action of nitrifying bacteria are oxidized in the soil into nitrate ions, which are well absorbed by plants. Nitrate fertilizers include KNO 3 and Ca (NO 3) 2. Ammonium nitrate fertilizers include, first of all, ammonium nitrate NH 4 NO 3, which contains both ammonia and nitrate nitrogen. The most concentrated solid nitrogen fertilizer is carbamide (urea), containing 46% nitrogen. The share of natural nitrate in the world production of nitrogen-containing compounds does not exceed 1%.
Application.
The development of new varieties of plants, including genetically modified ones, and improved agricultural techniques do not negate the need to use artificial fertilizers. Indeed, with each harvest, fields lose a significant proportion of nutrients, including nitrogen. According to long-term observations, each ton of nitrogen in nitrogen fertilizers increases the yield of wheat by 12–25%, beets by 120–160%, and potatoes by 120%. In our country, over the past half century, the production of nitrogen fertilizers at the nitrogen fertilizer plants has increased tenfold.
Ilya Leensonne
- (Alchem.) The creative principle in Nature, most of which is stored in the Astral Light. It is symbolized by a figure representing a cross (see. Theosophical Dictionary
In the dacha and vegetable garden business, nitrogen fertilizers are the main substance that provides the plant with a good compaction of the roots, the appearance of new leaves, the growth of flowers and the development of fruits.
Nitrogen replenishment is especially important for fruit and berry crops. It provides an increase in the growth of fruits and improves their taste. Nitrogen is easily assimilated in such types of soil as podzolic, peat, black soil.
A lot of nitrogen is found in organic compounds, however, this form acts as a kind of bait for many pests. Under the influence of a large number of insects, the plant may not survive. Therefore, summer residents use a form of nitrogen fertilizer based on minerals that is more useful for horticultural crops.
With an insufficient amount of nitrogenous fertilizers, the plant grows very weakly, the vegetative organs develop slowly, the leaves grow small, their appearance is colored with a yellowish tint, and soon they crumble prematurely. These processes have a detrimental effect on the plant, and can lead to an interruption in the flowering period and a reduction in fruiting.
Timely and correctly applied nitrogen mineral fertilizers will contribute to the healthy development of the plant and obtain the desired result for the summer resident.
Liquid nitrogen fertilizers
The production of liquid fertilizers is much cheaper than their solid counterparts. Therefore, liquid fertilizers can be purchased at lower prices. The effectiveness of such fertilizers does not depend on their natural state.
Most summer residents who are just starting gardening are interested in what liquid nitrogen fertilizers are they?
There are three main types of nitrogen compounds for soil fertilization:
- Anhydrous ammonia;
- Ammonia water;
- Ammonia.
Anhydrous ammonia. A fairly concentrated solution that looks like a colorless liquid. Anhydrous ammonia is created in the factory, as a result of the liquefaction of ammonia from a gaseous state under the influence of high pressure. The resulting liquid contains 82.3% nitrogen.
Liquid nitrogen fertilizer is stored in tightly closed containers. Do not store it in containers made of copper, zinc or similar alloys. It is recommended to use iron containers, or steel and cast iron. Anhydrous ammonia must be stored in closed containers as it tends to evaporate quickly.
Ammonia water. The nitrogen concentration in this fertilizer is about 16.4% minimum and up to 20.5% maximum. It does not have a destructive effect on ferrous metals. The ammonia water has a low pressure, which allows it to be stored in carbon steel vessels. It is not profitable and not practical to use this type of liquid nitrogen fertilizer over long distances, since nitrogen tends to evaporate quickly. Nitrogen-based fertilizer loses some of its original properties during transportation.
The application of nitrogen fertilizer to the soil is quite simple, but nitrogen losses can also occur as a result of the evaporation process of free, anhydrous ammonia. Soil colloids absorb nitrogen instantly. A small part of nitrogen fertilizers, as a result of reaction with soil moisture, turns into ammonium hydroxide.
In saturated soils, the efficiency of nitrogen fertilization increases several times. In this case, the loss of ammonia is minimal.
In sandy loam and sandy, unstable soils with a minimum saturation of humus, the loss of ammonia increases several times, respectively, the effectiveness of the application decreases.
In the presence of large volumes of land that need fertilizing with nitrogen fertilizers, there is a special technique. With its assistance, fertilizer is applied to a depth of 12 cm on light soils. This is done to minimize nitrogen losses and increase its efficiency. Surface application to the soil will not give any result.
Fertilizers containing nitrogen are also applied to frozen soil in the fall, or when cultivating the soil before the sowing campaign.
Ammonia. Ammonia production is carried out by mixing aqueous ammonia and nitrogen fertilizers. The resulting composition has about 30-50% nitrogen. It is found in ammonia in different compounds and proportions (nitrate and amide forms)
For horticultural crops, liquid ammonia is not inferior in properties to solid nitrogen fertilizers.
The soil should be replenished with liquid fertilizers in a special uniform to prevent it from getting on the skin and in the respiratory tract, as well as on the mucous membranes. Use goggles to protect your eyes and use masks or respirators to protect your breathing.
Types of nitrogen fertilizers and methods of their application
Nitrogen is one of the main components of the plant nutrition complex. Its main function in this complex is to increase the fertility of horticultural crops.
As for the doses for application to the soil, the norm for berry and fruit crops is 9-12 g / 1m 2 of soil. For crops that have a seed inside, these values are equal to 4-6 g / 1m 2 of soil. With simple top dressing, to maintain the general condition of the fruit, a dosage of up to 4 g / 1 m2 of area is applied.
The main types of nitrogen fertilizers:
Nitrogen fertilizers play an important role in the good development of horticultural crops. The main task for the summer resident is the timely feeding of the plant with this type of fertilizer. How to use nitrogen fertilizers, and in what proportions, are detailed in the instructions on the packages and in information sources.
The use of nitrogen fertilizers for fruit trees (video)
The term "nitrogen-containing fertilizers" usually causes a negative reaction among summer residents who have little experience in growing garden and garden plants, as well as among supporters of organic farming. Few people think that "environmentally friendly" manure or bird droppings are organic nitrogen fertilizers, and their excess is harmful to human health no less than the so-called "chemistry". This article will address the questions of what nitrogen fertilizers are and what types of them are used in personal plots.
Nitrogen in plant life
The role of nitrogen and its derivatives in plant life can hardly be overestimated. Metabolic processes at the cellular level occur in plants with the participation of protein, which is a building material for cell division, the synthesis of chlorophyll, trace elements, vitamins, etc.
Nitrogen is a chemical element that is an important component of vegetable protein. With its lack, all organic processes in cells slow down, plants stop developing, begin to ache and wither.
Nitrogen for all plants is as important and necessary as sunlight and water; without it, the process of photosynthesis is impossible.
Most of the nitrogen in a bound form (organic chemical compounds) is contained in the soil, rich in humus and waste products of worms (biohumus). The maximum concentration of nitrogen (up to 5%) is recorded in chernozem, the minimum - in sandy and sandy loam types of soil. Under natural conditions, the release of nitrogen in a form suitable for assimilation by plants occurs rather slowly, therefore, when growing crops, it is customary to use fertilizers containing nitrogen in a form that is easily absorbed by the roots. They contribute to:
- accelerated vegetation of crops;
- elimination of the deficiency of amino acids, vitamins and minerals;
- building up green mass of plants;
- easier assimilation of nutrients from the soil by plants;
- normalization of soil microflora;
- increasing disease resistance;
- increased productivity.
However, it should be remembered that not only a lack of nitrogen in plants is harmful, but also its excess, which contributes to the accumulation of nitrates in vegetables and fruits. An excess of nitrates used in food can cause significant harm to human health.
Signs of a lack and excess of nitrogen in plants
The use of fertilizers directly depends on the composition of the soil, its chemical composition, fertility, acidity, structure, etc. Depending on these factors, the required amount of fertilizers is determined and top dressing is carried out.
Lack of nitrogen
With an insufficient concentration of nitrogen, this immediately affects the appearance of the plants, their tone, namely:
- leaves become small;
- the green mass is thinning;
- foliage loses color, turns yellow;
- leaves, shoots and fruit ovaries die off en masse;
- plants stop growing;
- the emergence of young shoots stops.
When such symptoms appear, it is necessary to fertilize with nitrogen-containing fertilizers.
Excess nitrogen
With an excessive nitrogen content, all the strength of the plants is spent on building up green mass, they begin to fatten and the following signs appear:
- large, "fat" leaves;
- darkening of the green mass, its excessive juiciness;
- there is a delay in flowering;
- ovaries either do not appear, or there are very few of them;
- fruits and berries are small, inconspicuous.
The main types of nitrogen fertilizers
Nitrogen fertilizers are chemical compounds containing nitrogen molecules in various forms that are used in agriculture to improve crop growth and improve the quality and quantity of crops. Initially, their classification implies division into two large groups:
- Mineral.
- Organic.
Mineral nitrogen fertilizers and their types (by groups):
- nitrate;
- ammonium;
- complex (ammonium nitrate);
- amide;
- liquid form.
Each of the groups includes its own types of fertilizers, which have different names and special properties, the effect on plants and the procedure for feeding.
Nitrate group
This group includes fertilizers, which include the so-called nitrate nitrogen, its formula is written as follows: NO3. Nitrates are salts of nitric acid НNO3. Nitrate fertilizers include sodium nitrate, calcium nitrate and potassium nitrate.
The chemical formula - NaNO3, is sodium nitrate (another name is sodium nitrate), in which the concentration of nitrogen is up to 16%, and sodium is up to 26%. Outwardly, it resembles an ordinary coarse-crystalline salt, it is highly soluble in water. The disadvantage is that during long-term storage, sodium nitrate cakes, although it absorbs moisture from the air poorly.
Consuming the nitrate component of the fertilizer, plants deoxidize the soil, reducing its acidity. Thus, sodium nitrate and its use on soils with an acidic reaction gives an additional deoxidizing effect.
The use of this species is especially effective when growing potatoes, beets, berry bushes, fruit crops, etc.
Calcium nitrate
The chemical formula - Ca (NO3) 2, is calcium nitrate (another name is calcium nitrate), in which the nitrogen concentration reaches 13%. It also looks very similar to table salt, but is highly hygroscopic, absorbs moisture well from the air, and damp. Stored in a moisture-proof package.
Its granular form is produced, during production the granules are processed with special water-repellent additives. Calcium nitrate copes well with excessive soil acidity, additionally providing a structuring effect. Calcium improves the processes of nitrogen absorption, has a general strengthening effect on almost all crops.
Potassium nitrate
Chemical formula - KNO3, it is potassium nitrate, nitrogen concentration - 13%, potassium - 44%. Externally, it is a white powder with a crystalline particle structure. It is used throughout the season, and especially during the period of ovary formation, when plants need a large amount of potassium, which stimulates fruit formation.
Usually potassium nitrate is applied under fruit and berry crops such as strawberries, raspberries, beets, carrots, tomatoes, etc. For all types of greens, cabbage, potatoes, it is not used.
Ammonium group
Ammonium is a positively charged NH4 + ion. When interacting with sulfuric and hydrochloric acids, ammonium sulfate and ammonium chloride are formed, respectively.
Chemical formula - (NH4) 2SO4, contains up to 21% nitrogen and up to 24% sulfur. Outwardly, it is a crystallized salt that dissolves well in water. It absorbs water poorly, therefore it is stored for a long time. Produced as a by-product in the chemical industry. Usually it is white, but when received in the by-product coke industry it is colored in different colors by impurities (shades of gray, blue or red).
Chemical formula - NH4Cl, nitrogen content - 25%, chlorine - 67%. Another name is ammonium chloride. Received as an accompanying substance in the production of soda. Due to the high concentration of chlorine, it is not widely used. Many crops react negatively to the presence of chlorine in the soil.
It should be noted that fertilizers of the ammonium group, with regular use, significantly increase the acidity of the soil, since plants absorb mainly ammonium as a source of nitrogen, and acid residues accumulate in the soil.
To prevent soil acidification, lime, chalk or dolomite flour are added along with the fertilizer at the rate of 1.15 kg of deoxidizer per 1 kg of fertilizer.
Ammonium nitrate group
The main fertilizer. Chemical formula - NH4NO3, nitrogen content - 34%. Another name is ammonium nitrate or ammonium nitrate. It is the product of the reaction between ammonia and nitric acid. Appearance - white crystalline powder, readily soluble in water. Sometimes it is produced in granular form, since ordinary nitrate has an increased ability to absorb moisture and cakes strongly during storage. Granulation eliminates this disadvantage. It is stored as an explosive and flammable substance in compliance with safety standards, because it can detonate.
Due to the double content of nitrogen in different forms, it is a versatile fertilizer that can be used for all types of agricultural plants on all soils. Both ammonium and nitrate forms of nitrogen are perfectly absorbed by all crops and do not change the chemical composition of the soil.
Saltpeter can be added for digging in the fall, in the spring when preparing the soil for planting, as well as in the planting holes directly when planting seedlings.
As a result, the shoots and deciduous mass are strengthened, and the endurance of crops increases. To prevent acidification of the earth, additives neutralizing acidity are introduced into the fertilizer - dolomite flour, chalk or lime.
Amide group
Urea
It is a prominent representative of the group, another name is urea. Chemical formula - CO (NH2) 2, nitrogen content - not less than 46%. Outwardly, it is a white salt with small crystals, quickly dissolves in water. It absorbs moisture moderately, with proper storage it practically does not cake. Also available in granular form.
According to the mechanism of chemical action on the soil, the amide type of fertilizer has a double effect - it temporarily alkalizes the soil, then acidifies it. It is considered one of the most effective fertilizers comparable to ammonium nitrate.
The main advantage of urea is that when it gets on the leaves, it does not cause burns, even at high concentrations, and is perfectly absorbed by the roots.
Liquid fertilizers
Liquid nitrogen fertilizers are distinguished by a higher degree of absorption by plants, a prolonged action and an even distribution in the soil. This type includes:
- anhydrous ammonia;
- ammonia water;
- ammonia.
Liquid ammonia. Chemical formula - NH3, nitrogen content - 82%. It is produced by liquefying its gaseous form under pressure. Outwardly, it is a colorless liquid, with a pungent odor, and evaporates easily. Stored and transported in thick-walled steel containers.
Ammonia water. Chemical formula - NH4OH. In fact, it is a 22-25% ammonia solution, colorless, with a pungent odor. It is transported in sealed containers under low pressure, easily evaporates in air. More suitable for use for feeding than anhydrous ammonia, but its main disadvantage is the low concentration of nitrogen.
UAN - urea-ammonia mixture. These are ammonium nitrate and urea (urea) dissolved in water. The nitrogen content is from 28 to 32%. The cost of these types is much lower, since there are no expensive procedures for evaporation, granulation, etc. The solutions contain almost no ammonia, so they can be freely transported and applied to plants by spraying or watering. They are widespread due to their relatively low cost, ease of transportation and storage, and versatility of use.
Ammonia. Chemical composition - ammonium and calcium nitrate, urea, etc., dissolved in ammonia. The nitrogen concentration is 30-50%. In terms of the effectiveness of the impact, they are comparable to solid forms, but a significant drawback is the difficulty of transportation and storage - in sealed low-pressure aluminum containers.
Organic fertilizers
Various types of organic matter also contain nitrogen, which is used for plant nutrition. Its concentrations are low, for example:
- manure - 0.1-1%;
- bird droppings - 1-1.25%;
- compost based on peat and food waste - up to 1.5%;
- green mass of plants - 1-1.2%;
- sludge mass - 1.7-2.5%.
Experts believe that the use of organic matter alone on a personal plot does not give the desired effect, and sometimes it can harm the composition of the soil. Therefore, it is preferable to use all types of nitrogen fertilizers.
How to use nitrogen fertilizers
It should be remembered that these are chemically active substances that can cause severe poisoning if they enter the human body. That is why you should strictly adhere to the recommendations for dosage and frequency of top dressing.
Each package contains complete information and instructions for use, they must be carefully studied before processing the beds.
When working with chemicals, you need to use personal protective equipment - gloves, goggles and suits to protect the skin and mucous membranes. When working with liquid forms of fertilizers, you must use a mask or respirator to protect the respiratory tract.
Particular attention should be paid to the storage of fertilizers and in no case should they be used after the expiration of the guaranteed shelf life and expiration date. Subject to all conditions, there will be no unpleasant consequences from the use of nitrogen fertilizers.
Thus, nitrogen fertilizers and their application on a personal plot can multiply the yield of crops, increase their resistance to diseases and pests, as well as restore the structure and fertility of the soil.
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