Nitrogen fertilizers: characteristics, groups, benefits for plants, top dressing. Fertilizers with amide form of nitrogen Nitrate form of nitrogen

Forms of nitrogen fertilizers

In a nitrogen fertilization system, the choice of the form of nitrogen is important. Nitrogen in The composition of fertilizers can be in various forms:

- Ammonia (NH 4). It binds well with the soil, is freely absorbed by the plant, including when low temperatures Oh. The ammonia form promotes the growth of the root system, tillering, better absorption of phosphorus, sulfur, boron, etc. It is recommended to apply under winter wheat in early spring, under sugar beet for cultivation and top dressing. Well absorbed in alkaline soils. It is desirable to earn in the soil.

best form nitrogen for pre-sowing application. Contained in saltpeter, ammonia water, ammonium sulfate, ammophos, nitrophoska.

- Nitrogen (NO 3). It is not retained by the soil and is easily washed out into deeper layers, it works better at higher temperatures. There is evidence that 3 mm of precipitation leaches nitrates 1 cm deep, i.e. if 60 mm of rain falls in a month, nitrates will move 20 cm deeper. Well absorbed in acidic soils. This form of nitrogen has a positive effect on the absorption of potassium, magnesium and calcium. There is no need to wrap in the soil. The best form of nitrogen for top dressing. It should be applied in those phases of vegetation when there is an intensive growth of plants. Contained mainly in various types of saltpeter.

- Nitrate-ammonia (NO 3, NH 4). The most versatile form of nitrogen fertilizer for pre-sowing application and top dressing.

- Amide (NH 2). In the soil, it should decompose first to the ammonia form, and later to the nitrogen form. Assimilated by plants more slowly than nitrogen and ammonia. It is a slow acting form of nitrogen. The higher the temperature, the faster the amide form of nitrogen works. It has a positive effect on reducing the accumulation of nitrates in the plant. It must be wrapped in the soil.

The best nitrogen fertilizer for the main application is urea, in which nitrogen is in the amide form and does not leach deep into the soil. However, at low temperatures nitrogen from urea is more difficult for plants to access.

Ammonium nitrate (NH 4 N0 3, (N34)). Ammonium nitrate fertilizer in the ratio NH 4: NO 3 = 1:1. In terms of efficiency, ammonium nitrate often ranks first among nitrogen fertilizers. It is the best fertilizer for feeding winter cereals and rapeseed. It is used in fertilizer systems in all soil and climatic zones of Ukraine for pre-sowing application and for top dressing. Water-soluble, physiologically slightly acidic, fast-acting nitrogen fertilizer.

The fertilizer is concentrated, contains almost no ballast compounds and quickly dissolves in water. A characteristic feature of ammonium nitrate is that the ammonium cations of the fertilizer are absorbed by the soil complex but are not washed out into the lower layers of the soil and are absorbed by the root system of plants for a long time. Ions of nitrate nitrogen fertilizers are not absorbed by soil colloids, are in a mobile state and are quickly absorbed. This is relevant for early spring feeding, when nitrification processes in the soil do not yet occur.

Ammonium and nitrogen forms of nitrogen are easily absorbed by the plant. The recommended average application rate of ammonium nitrate is 3-4 c/ha, up to 6 c/ha.

It is advisable to use in the spring for feeding winter crops, spring cereals, oilseeds, sugar beets.

Under conditions of sufficient moisture, the nitrate form of nitrogen can be washed out, therefore, saltpeter is used for spring-summer top dressing, or applied in the spring with incorporation into the soil before sowing. In areas with insufficient moisture supply, it can be applied from autumn. Saltpeter is also used for fertilizing tilled and vegetable crops with the obligatory simultaneous incorporation into the soil by a cultivator during inter-row loosening.

When processing saltpeter granules at chemical plants with special anti-shrink agents (lylamine), it can be stored in polypropylene containers for 6-8 months.

Ammonium nitrate is a good component for the production of mixtures of mineral fertilizers.

Lime ammonium nitrate (NH 4 NO 3 + CaCO 3, (N27Ca12)). Universal, nitrogen-carbonate, neutral fertilizer. It is characterized by high efficiency on acidic soils. Lime-ammonium nitrate has better physical and mechanical properties compared to ammonium nitrate and urea. Does not acidify the soil.

Sodium nitrate (NaNO 3, (N15-16)). Well soluble in water. The fertilizer is physiologically alkaline. When applied to the soil, nitrate nitrogen remains in the soil solution, while sodium is absorbed by the soil absorbent complex. Nitrogen is easily absorbed by plants, but its significant disadvantage is the ability to be washed out and lost. It is recommended to apply on acidic soils.

Ammonium sulfate ((NH 4) 2SO 4, (N21 S24)). It is a crystalline salt of white, yellowish or gray color, highly soluble in water.

The fertilizer is more physiologically acidic than ammonium nitrate. It is recommended for application on non-acidic (saturated with bases) soils and on acidic soils during liming.

Can be applied in autumn. Fertilizer valuable sulfur content. Slow-acting fertilizer for the main or pre-sowing application.

When introduced into the soil, ammonium sulfate dissolves quickly. The ammonium group is absorbed by the soil absorbent complex, keeps nitrogen from being washed out. Due to good sorption in the soil, it is not washed out and is the only source of nitrogen for plants for a long time.

If the fertilizers used during the main application did not contain sulfur, then potatoes can be fed with ammonium sulfate, preferably 8-15 days after planting the tubers. Scattered fertilizers are incorporated into the soil during mechanical loosening.

A single application of ammonium sulfate, even on podzolic soils, does not significantly affect the change in the reaction of the soil solution, and the systematic use of this fertilizer on podzolic and podzolized soils leads to acidification of the soil solution. This feature of the fertilizer is taken into account when using it, simultaneously liming the soil.

On chernozems, the use of ammonium sulfate on the development of plants from does not negatively affect.

Carbamide (urea) ((NH 2) 2CO, (N46)). Amide fertilizers- the most concentrated among solid nitrogen fertilizers. It is synthesized from two gases CO 2 and NH 3 at a temperature of 185-200°C and a pressure of 180-200 atmospheres. Water-soluble, slow-release, nitrate-free fertilizer with an almost neutral reaction.

It is used in fertilizer systems in all soil and climatic zones of Ukraine in the main application and for foliar foliar feeding. In the fertilization system, vigorous grain crops are introduced into pre-sowing cultivation. It is more expedient to use carbamide for crops with a long growing season - beets, corn for grain. In the soil, the amide form is transformed into ammonia, and later - nitrate. This process occurs slowly, so nitrogen from urea is evenly assimilated by plants during the growing season, and does not accumulate excessively in the plant and in groundwater. Little is washed out of the soil, the loss of nitrogen in the soil is minimal. Fertilizer should not contain more than 0.8% biuret and 0.3% water, this is especially important in puff application. The amide form of nitrogen is rapidly absorbed through sheet surface.

During the granulation process, biuret is formed in the urea. According to the content of 3%, biuret is toxic to plants, so the application immediately before sowing inhibits the development of plants. In the soil, biuret completely decomposes in 10-15 days - this interval is recommended to be maintained between the introduction of carbamide into the soil and sowing. Biuret content of 0.8% and below does not have a negative effect on plant seedlings, regardless of the period of fertilizer application (it can be applied immediately before sowing).

The higher the soil temperature, the better and faster the absorption of nitrogen from urea. On soils that are very acidic or freshly limed, it has a lesser effect. Less effective also on waterlogged, cold soils and during early spring application on winter crops.

A single application of urea should not exceed 2.5 c/ha. Carbamide needs to be applied to the soil, since losses during surface application are 20-30% higher than in saltpeter. With the surface introduction of NH 4 NO 3, nitrogen losses are 1-3%, and CO (NH 2) are already 20-30%. With the surface application of urea to the soil without immediate incorporation, gaseous losses of nitrogen in the form of ammonia can reach 30-50%.

Permissible concentration of urea solution for foliar top dressing of cereals is 5-30%. The content of biuret should not exceed 0.3%.

Ammonia water ((NH4OH), (N20)). Ammonia solution in water. Mass fraction of nitrogen 20.5%. The fertilizer is physiologically acidic. Nitrogen is found in the forms of free ammonia (NH 3) and ammonium (NH 4 OH). The content of ammonia is greater than ammonium. To avoid nitrogen losses, it is better to apply before plowing or after plowing, before sowing winter crops to a depth of 10-18 cm, in spring before sowing fertile crops and in summer to feed tilled crops.

Surface application is unacceptable, since ammonia evaporates quickly.

Phosphate fertilizer groups

According to the degree of solubility, phosphate fertilizers are divided into three groups s:

1. Water-soluble and readily available for all plants (monosubstituted phosphates: Ca (H 2 PO 4) 2, Mg (H 2 PO 4) 2, K 2 H 2 PO 4, NaH 2 PO 4, NH 4 H 2 PO 4, etc. ..) - various types of superphosphates, ammophos, nitroammophos.

2. Insoluble in water, but soluble in weak acids (citric) or in alkaline citric solutions (disubstituted phosphates: CaHPO 4 , MgHPO 4) - partially available for plant nutrition.

3. Insoluble in water and weak acids (trisubstituted: Ca 3 (PO 4) 2, Mg 3 (PO 4) 2) - hard-to-reach for plants - phosphate rock. Partially it can be used by crops whose root system is capable of secreting weak organic acids (buckwheat, mustard, lupine, peas).

The coefficient of phosphorus assimilation is very low (15-30%) as a result of the rapid conversion of the introduced soluble phosphorus into phosphates that are inaccessible to plants. Therefore, to increase the content of mobile phosphates in the soil, on sandy and sandy soils, it is recommended to add P40-60, on light and medium loamy soils - P60-90 and heavy loamy - P90-120.

Superphosphate granulated . Ca (H 2 PO 4) 2-H 2 O + H 3 PO 4+2CaS0 4 , (P20 S11 Ca30)

Physiologically acidic, water-soluble phosphate fertilizer. Contains more than 30% calcium sulfate, which has practical value as a source of sulfur (11%). It is used for the main and pre-sowing application in fertilizer systems in all soil and climatic zones of Ukraine, for all crops. It is characterized by slow and uniform release of batteries. The composition of the fertilizer includes trace elements: B, Cu, Mn, Mo, Zn. Valuable fertilizer for cruciferous crops (rapeseed, etc.), and legumes.

Superphosphate ammoniated granular.

NH 4 H 2 PO 4 + Ca (H 2 PO 4) 2 x H 2 O + CaSO 4 + H 3 PO 4 - brand N3: P17: S 12

It is used in fertilizer systems in all soil and climatic zones of Ukraine. In addition to 3% nitrogen and 17% phosphorus, it contains 12% sulfur (40-55% calcium sulfate CaSO 4), which is especially valuable on soils where it is necessary to additionally include sulfur-containing fertilizers in the fertilizer system. It is better to use for legumes, cruciferous oilseeds that are demanding on sulfur nutrition.

Fertilizer application rates are calculated based on the results of agrochemical analyzes of the soil, climatic conditions, biological needs and programmable yield. Optimal rate ammoniated superphosphate for winter wheat is 3-6 c/ha, for sugar beet - 5-8 c/ha. The best way making - on the stubble before plowing.

The fertilizer is chemically acidic, water-soluble. Due to the neutralization of the acidic action by ammonia, it does not acidify the soil, unlike superphosphate. It has a minimum of 10% higher efficiency compared to traditional superphosphate.

Phosphate flour. Ca 3 (PO 4) 2 x CaCO 3, (P18-20 Ca3 4)

Contains trisubstituted phosphorus in the form of Ca 3 (PO 4) 2, which is insoluble in water, but only in weak acids. Great importance in improving the efficiency of phosphate rock has a degree of grinding. The smaller the better. The remainder of the particles that do not pass through the sieve holes with a diameter of 0.18 mm is allowed, not more than 10%.

Phosphorus in fertilizer is in a hard-to-reach form. Its effectiveness increases on acidic soils with a pH of 5.6 and below.

The availability of phosphorus from flour for most crops is low. It is absorbed only by cultures whose root system has acid secretions, namely: lupine, buckwheat, mustard. Cereal crops poorly absorb phosphorus from this fertilizer.

The effectiveness of phosphorus flour increases significantly when it is composted with organic fertilizers. Promotes the transfer of phosphorus into accessible forms by sowing green manure, especially white mustard, which absorbs it well. The next crop already uses phosphorus, which is released during the decomposition of green manure biomass.

The application rate of phosphorus flour for the main treatment is 5-20 c/ha once every 5-6 years to provide phosphorus and especially calcium. This fertilizer is primarily a good ameliorant for radical improvement of the soil, in particular the reduction of its acidity.

In such fertilizers as nitrophos, nitrophoska, more than half of the phosphorus is in a hard-to-reach state, so it is advisable to apply them on acidic soils to the main fertilizer (for plowing).

potash fertilizers

Potassium chloride granular, potassium chloride fine-grained (KS1, (K 6 0))

In the world, among the entire range of potash fertilizers, more Potassium chloride is used more - 80-90%.

It is used in fertilizer systems in all soil and climatic zones of Ukraine (except solonetsous soils) for the main tillage for crops that are not sensitive to the harmful effects of chlorine. When applied under plowing, chlorine is washed into the deep layers of the soil, which reduces the possibility of getting into the plant. It is a highly concentrated fertilizer, water-soluble, physiologically acidic.

Potassium salt((KCl + NaCl), (K 4 0)). The fertilizer is water-soluble, physiologically acidic. Contains 20% NaCl 2-3% MgCl. It is used in all soil-climatic zones in autumn for the main tillage for crops (beets, cereals, grasses) that are not sensitive to the harmful effects of chlorine.

Kalimagnesia((K 2 SO 4 x MgSO 4 x 6H 2 O), (K28 Mg8 S15)). Two grades are produced: in grade "A" the potassium content is 28%, in grade "B" - 25%.

The magnesium content in both grades is 8%. It is used in all soil and climatic zones. High fertilizer efficiency is observed on soils that have a low supply of magnesium and on crops that are sensitive to the harmful effects of chlorine (buckwheat, potatoes, soybeans, peas, flax, vegetables, tobacco, grapes). Due to the presence of magnesium, which has a positive effect on growth processes, carbohydrate synthesis, fertilizer is especially effective on light soils.

Also valuable is the sulfur content, which can reach 15%. This is one of the best fertilizers.

Cainite natural ((KCl x MgSO 4 x ZN 2 O)). Raw, low concentrated fertilizer, mass fraction potassium (K 2 0) is at least 9.5%, 6-7% MgO, 22-25% Na 2 0.

Appears dark gray or red large crystals. The fertilizer is water-soluble, chlorine. It is recommended to apply from autumn for the main tillage for sugar, fodder beet, perennial herbs. Offered in bulk. Its disadvantage is the low content of potassium and the high content of chlorine. For 1 kg of K 2 O, there are 3.3 kg of chlorine. Valuable is the content of magnesium, sulfur, sodium.

potassium sulfate(K 2 S0 4 , (K45-52 S45)). Valuable chlorine-free potash fertilizer, physiologically acidic (pH-4), water-soluble. It is recommended to apply under all cultures, especially sensitive to chlorine. Valuable fertilizer for vegetable crops, for use in greenhouses. The presence of sulfur makes this fertilizer very valuable for application under cruciferous, legumes and other crops that react positively to sulfur fertilizers.

Suitable for feeding in dissolved form. Foliar top dressing is carried out with a working solution concentration of 1-3%.

The concentration of the working solution for fertigation: greenhouses -0.01-0.05% (0.1-0.5 kg per 1000 liters of water), open ground - 0.01-0.1% (0.1-1 kg 1000 l of water).

This fertilizer is very expensive, which limits its about use.

Complex fertilizers

Advantages of complex fertilizers:

One granule contains two or more elements elements of mineral nutrition, which ensures their high positional availability to plants;

High quality of a granulation: uniformity of introduction;

Concentrated, contain less ballast compounds, it is possible to use in conditions of insufficient moisture;

Various grades are produced with a wide range of use on all types of soils and ensuring the physiological characteristics of various crops;

Provide constant yield, improved quality and environmental friendliness of products that can be used for baby and diet food;

Provides reduced transport costs handling, storage and use.

Nitroammophoska (azofoska) (N16P16K1 6). One of the best fertilizers. Fertilizer - concentrated, nitrogen-phosphorus-potassium, granulated, is produced in various grades with different content and ratio of mineral nutrition elements: N: P: K = 16:16:16, 15:15:15 and others.

The main elements of mineral nutrition are contained in the form of water-soluble and easily accessible compounds for plants: NH 4 H 2 PO 4, (NH 4), HPO 4, NH 4 NO 3, NH 4 Cl, KCl, KNO 3, CaHPO 4

The phosphorus of nitroammophoska is more mobile in the soil than the phosphorus of superphosphate, and is easily absorbed by plants. Each granule contains the same amount of nitrogen, phosphorus and potassium, useful material are evenly distributed in the soil, surpassing fertilizer mixtures in this indicator.

Physiologically neutral fertilizer. The efficiency of nitroammophos fertilizer increases with the additional application of nitrogen fertilizers. The optimal application rate of nitroammophoska for sugar beet is 8-10 c/ha, for winter wheat 5-8 c/ha. In autumn, 3-4 c/ha is applied after grain predecessors, where straw is used as fertilizer. After other (best) predecessors, the norm of autumn application is no more than 1-2 q/ha.

It is better to use nitroamofoska for early spring feeding (3-5 centners/ha) of winter wheat on thawed soil. It is very important for the first feeding of winter crops instead of saltpeter to use nitroamophoska in areas where phosphorus and potassium are not applied for the main treatment, or the application rate of these fertilizers is not residual for the formation of a programmable yield.

diammofoska marks 10:26:26. The fertilizer is highly concentrated, granular, contains significantly less free chemical acids compared to nitroammophoska, therefore it is considered chemically neutral. Biogenic elements are contained in the forms of water-soluble and readily available compounds for plants: NH 4 H, PO 4, (NH) 3HPO 4, NH 4 NO 3, NH 4 Cl, KCl, KNO 3.

It is advisable to use in the fall for winter crops, malting barley and for feeding sugar, table beet, potatoes, vegetable crops during the growing season. Diammofoska can be applied superficially with subsequent incorporation into the soil, but it is also advisable to use it locally into the soil using a tape method to a depth of 8-10 cm.

Potassium nitrate (potassium nitrate) (KNO 3), (N14, K46). Concentrated nitrogen-potassium physiologically neutral fertilizer. Fine crystalline powder. Completely water soluble fertilizer. Does not contain salts (Сl and Na) and heavy metal compounds. Nitrogen in the nitrate form does not evaporate, improves the absorption of other cations (Ca, Mg ...).

Potassium nitrate is important source replenishment of plants with potassium. Suitable for all crops in all phases of development.

The ratio of nitrogen and potassium (1:3.5) in the fertilizer allows it to be used to feed all crops, it is especially effective on soils that have an average and high level of phosphorus compounds.

It is better to apply in the spring, because when applied in the fall, the nitrate nitrogen contained in the fertilizer is washed out during the autumn-winter period by precipitation into the lower layers of the soil, which leads to groundwater pollution, and it becomes almost inaccessible for plant nutrition.

It is used in the nutrition systems of crops sensitive to the harmful effects of chlorine-potassium fertilizers.

Recommended for use in fertigation systems and foliar applications. It is used for foliar foliar feeding of winter wheat in the heading phase at a dose of 3-6 kg/ha for a working solution volume of 200-250 liters of water per hectare, as well as for the preparation of mixtures of mineral fertilizers.

One of the best fertilizers to use with drip irrigation. For greenhouse plants up to 0.5% concentration (50 g per 10 l of water), for open ground plants - 0.5-1.0% concentration (50-100 g per 10 l of water).

calcium nitrate (calcium nitrate) 5Ca (NO 3) 2 + NH 4 NO 3 x 10H 2 O, (N15, Ca26).

Physiologically alkaline fertilizer, highly soluble in water, hygroscopic. Contains water-soluble calcium, which is readily available for plant nutrition. Best used on acidic sod-podzolic soils. It is characterized by fast action even under adverse conditions. climatic conditions: low temperature, excessive humidity, drought, low pH. The use of calcium nitrate promotes the absorption of calcium, magnesium, potassium and other cations due to nitrate nitrogen, which is part of the fertilizer. The high efficiency of calcium nitrate is observed when applied locally to the soil to a depth of 8-10 cm, although production experience confirms good results when applied superficially. The loss of nitrate nitrogen fertilizer during use is negligible.

The main agrochemical features of calcium nitrate:

Stimulates the development of the root system (core roots - root hairs) and vegetative growth and development of agricultural and ornamental crops (sugar beet, fodder beet, table beet, potatoes, winter and spring rapeseed, grain corn and silage, soybeans, cabbage, tomatoes, cucumbers, beans, parsley, apple trees, strawberries, roses, chrysanthemums, carnations)

Improves the formation of membranes and cell walls in plants;

Activates the activity of enzymes and metabolism in plants;

Improves processes of photosynthesis, transportation of hydrocarbons and assimilation of nitrogen in plants;

Increases plant resistance to environmental stress factors, fungal and bacterial diseases that occur due to calcium deficiency - creamy rot of tomatoes, peppers, browning of potato pulp, bitter pitting of apple fruits.

Improves keeping quality of fruits and vegetables during storage and transportation;

Increases yield by 10-15%, improves presentation and taste qualities vegetables and fruits;

Physiological alkaline fertilizer (1 q equivalent to 0.2 q CaCO 3), which is effective on acidic and alkaline soils.

Calcium nitrate is also used for foliar application at a concentration of 0.5-2.0%, especially when symptoms of calcium deficiency appear in plants. High efficiency from foliar feeding with calcium nitrate is observed in regions with a hot arid climate and high solar insolation. Recommended for use on beets, vegetables, rapeseed, wheat, etc.

Do not mix calcium nitrate with fertilizer ions containing phosphates and sulfates.

Ammophos(NH 4 H 2 PO 4 , (N12, P52)). Complex highly concentrated nitrogen-phosphorus granular fertilizer. Compounds of nitrogen and phosphorus contained in the fertilizer are water-soluble (the content of water-soluble monoammonium phosphate (NH 4 H 2 P0 4) is 85-90%, and citrate diammonium phosphate (NH 4) 2HPO 4 is 10-15%) and readily available to plants. It is used in fertilizer systems in all soil and climatic zones of Ukraine.

The optimal application rate for winter wheat is 1-2 c/ha, for sugar beet - 2-4 c/ha, preferably on stubble before plowing. Ammophos phosphorus is less bound by soil than superphosphate phosphorus. Probably the reason for this is the formation of ammonium, which contributes to the dissolution of phosphates and their transformation into more accessible forms for plants.

In ammophos, phosphorus is more mobile than in superphosphate. The nature of the transformation of ammophos in soddy-podzolic soil largely depends on the level of its cultivation. On acidic soils, ammophos, as the most soluble form, retrograded faster than other fertilizers, which led to a decrease in the content of mineral phosphates in the soil and an increase in the fraction of organic phosphorus and inaccessible phosphates compared to soil fertilized with superphosphate. Liming of such soils also did not reduce the amount of ammophos phosphorus retrogradation. On neutral and slightly alkaline soils, ammophos provides a more favorable phosphorus regime. them compared to superphosphate.

Liquid complex fertilizers stamps 8-24-0; 10-34-0. These are solutions of nitrogen and phosphorus. The ZhKD 8-24-0 brand is made on the basis of evaporated orthophosphoric acid, and the ZhKD 10-34-0 brand is based on superphosphoric acid.

The ammonia form of nitrogen in fertilizers is chemically bound with ortho- and polyphosphoric acids and therefore is transported in leaky closed containers and applied to the soil surface without simultaneous sowing.

In the system of mineral nutrition, LCD 10-34-0 can be used with herbicides, macro- and microfertilizers, growth stimulants in one working solution, respectively, the agro-economic efficiency of intensive technologies for growing crops increases. Fertilizer is also applied locally in the soil by a belt method to a depth of 8-10 cm by special plant feeders. It is used in mineral nutrition systems of all soil and climatic zones of Ukraine. It is advisable to apply in the zone of insufficient moisture and on carbonate soils saturated with basics, with an alkaline pH.

Monopotassium phosphate (KN 2 RO 4, (K34, P50)). One of the most concentrated phosphate-potassium fertilizers. Completely water soluble, high level uptake by plants. Increases the yield and quality of fruits and vegetables due to an increase in the content of sugars and vitamins, improves wintering ornamental trees and bushes. For foliar feeding, a solution of 0.1-0.2% concentration is used.

Mainly used in systems drip irrigation, hydroponics and for foliar feeding of vegetable, fruit, ornamental crops, vineyards on all types of soils and substrates.

The mass fraction of phosphorus (P 2 O 5 - 52%, P - 23%) and potassium (K 2 O - 34% K - 28%) is high. Therefore, the fertilizer is also used for the production of liquid and solid mixtures of mineral fertilizers.

The use of fertilizer increases the resistance of plants to fungal diseases.

Monopotassium phosphate should not be mixed with drugs containing calcium and magnesium.

magnesium nitrate(N 9 Mg 8). Fully water soluble foliar fertilizer in greenhouses and open ground. Provides the need for plants in magnesium during the growing season.

Application rate on grain crops and grasses - 10-20 liters in 400 liters of water per 1 ha, on potatoes and root crops - 6-10 liters in 400 liters of water per 1 ha, on vegetable crops - 4 liters in 400 liters of water per 1 ha.

Magnesium sulfate(MgS0 4 x H 2 O, Mg26 S21). A valuable source of magnesium and sulfur for agricultural crops. Water-soluble fertilizer as impurities contains Na 2 0 (0.1%), Cl (0.2%), Fe (0.01%), Mn (0.01%).

Used for the main application for vegetables (70-150 kg/ha), field (120-160 kg/ha) and fruits (300-500 kg/ha) and for top dressing - 30-50 kg/ha every 10-20 days .

Foliar application is carried out 1 time in 3-4 weeks with a solution of 1.5-2% during the growing season. Quickly eliminates the lack of magnesium in the leaves.

Highly effective - it is used normally half as much as magnesium sulphate seven-shaped (epsomite). Epsomite (MgS0 4 x 7H 2 0) is used at a 5% concentration, and kieserite (MgS0 4 x H2O) at a 2.5% concentration.

Urea CO(NH 2) 2 contains 46% nitrogen. Urea is the most concentrated nitrogen fertilizer available in granular form. During granulation, to reduce caking, the granules are coated thin film fat supplement. Granular urea has good physical properties, practically does not cake, and maintains good dispersibility. However, during granulation under the influence of temperature, biuret is formed in it:

2CO(NH 2) 2 → (CONH 2) 2 HN+NH 3 . At its content of more than 3%, plant growth is inhibited, therefore, biuret should not exceed 1% in granular urea. In this amount, it does not adversely affect plant seedlings. In the soil, under the influence of urobacteria that secrete urease, urea is ammonified, forming ammonium carbonate:

CO (NH 2) 2 + 2H 2 O \u003d (NH 4) 2 CO 3.

At favorable conditions on humus-rich soils, urea turns into ammonium carbonate in 2-3 days. On infertile sandy and marsh soils, this process is weaker.

Ammonium carbonate is a fragile compound. In air, it decomposes to form ammonium bicarbonate and ammonia gas:

(NH 4) 2 CO 3 → NH 4 HCO 3 + NH 3. Therefore, with the surface application of urea without incorporation into the soil and in the absence of precipitation, there may be partial losses of nitrogen in the form of ammonia, especially on soils with a neutral and alkaline reaction. At the ammonification stage, urea temporarily alkalizes the soil:

(NH 4) 2 CO 3 + H 2 O \u003d NH 4 HCO 3 + NH 4 OH.

At the stage of nitrification, the soil reaction shifts towards the acid interval. However, as a result of the assimilation of nitrogen by plants, neither alkaline nor acidic fertilizer residues remain in the soil.

Urea is a valuable nitrogen fertilizer. Used for various cultures. In terms of its effect on the crop of agricultural plants, it can be put on a par with NH 4 NO 3. In a zone of sufficient moisture on light soddy-podzolic soils and during irrigation on gray soils, urea is more effective than ammonium nitrate, since the amide nitrogen of urea quickly turns into ammonia, and the latter is absorbed by the soil and less washed out. With the main application in rainfed conditions, it is equivalent to ammonium nitrate. Urea is highly effective for feeding winter crops with subsequent immediate incorporation by harrowing, as well as for feeding tilled field and vegetable crops by cultivators-plant feeders.

Urea is also used in the form of a solution for foliar feeding of plants, especially wheat, to increase its protein content. In this case, it is better to use crystalline urea, since it contains less biuret (0.2-0.3%).

Urea is widely used not only as a direct fertilizer, but also as a component for the production of complex fertilizers, as well as for the production of new types of slow-acting nitrogen fertilizers. Due to the higher efficiency of using urea and other highly concentrated nitrogen fertilizers, low-percentage nitrogen fertilizers are gradually losing their importance in the overall balance of nitrogen fertilizer consumption.

calcium cyanamide CaCN 2 contains 20-21% nitrogen. It is a light black or dark gray powder, physiologically alkaline fertilizer (up to 20-28% CaO). Systematic application on acidic soils improves its physical properties by neutralizing acidity and enriching with calcium. They are applied in advance, 7-10 days before sowing or under fall. It is not recommended for top dressing, since calcium cyanamide undergoes hydrolysis in the soil and interacts with the absorbing complex. This produces cyanamide (H 2 CN 2), which is poisonous and has an anesthetic effect on plants. However, it quickly turns into urea, and therefore its advance application is recommended.

Liquid nitrogen fertilizers

Anhydrous ammonia(NH 3) - the most concentrated non-ballast fertilizer with a nitrogen content of 82.3%. It is obtained by liquefying gaseous ammonia under pressure. It is a colorless liquid in appearance with a specific gravity of 0.61 at 20°C. When stored in open containers, it evaporates quickly. Therefore, it is stored and transported in special thick-walled steel tanks designed for a pressure of 25-30 atm. At 20-40°C, its pressure is from 9 to 18 atm. vapor pressure, specific gravity and the nitrogen content in 1 m 3 of anhydrous ammonia vary with temperature. When ammonia is stored in hermetic pressure vessels, it separates into two phases: liquid and gaseous. Due to the high vapor pressure, storage and transportation tanks for liquid ammonia are not completely filled. Liquid ammonia corrodes copper, zinc and their alloys, but is practically neutral with respect to iron, cast iron, steel.

ammonia water(aqueous ammonia) - a solution of ammonia in water. The first grade of this fertilizer contains 20.5% nitrogen (25% ammonia), the second - 16.4% nitrogen (20% ammonia). Ammonia water has a low pressure, does not destroy ferrous metals. Therefore, to work with it, tanks made of ordinary carbon steel are used. At a temperature of 15°C, the density of aqueous ammonia of the first grade is 0.910, the second - 0.927. 25% aqueous ammonia freezes at -56°C, 20% at -33°C. Nitrogen in ammonia water is found in the form of ammonia (NH 3) and ammonium (NH 4 OH). Moreover, free ammonia contains much more than ammonium, which causes possible losses of nitrogen due to volatilization. Working with ammonia water is easier than with anhydrous ammonia, but it is not very transportable due to the low nitrogen content, so it is more economical to use ammonia water in farms located near enterprises producing this fertilizer.

The ammonia introduced into the soil is quickly adsorbed by it, and also absorbed by soil moisture, turning into ammonium hydroxide. Ammonia in the soil undergoes nitrification. The intensity of ammonia uptake by the soil depends on its mechanical composition, humus content, moisture content, fertilizer application depth, etc. On heavy, highly humus and well-cultivated soils, ammonia is absorbed better than on light soils poor in humus. In this regard, from soils of light mechanical composition and dry ammonia evaporates faster.

All liquid nitrogen fertilizers should not be applied superficially and shallowly, especially in dry sandy soil, to avoid losses from volatilization. These fertilizers are applied by special machines and embedded on heavy soils to a depth of at least 10-12 cm, and on light soils - 14-18 cm. In all cases, anhydrous ammonia is embedded to a depth of at least 14-15 cm, and water - 10-12 cm If the soil is coarse-lumpy, then the depth of incorporation of these fertilizers increases by 1.2-1.5 times. They are applied as the main method for autumn plowing, in spring - for pre-sowing cultivation and for fertilizing row crops in the same doses (for nitrogen) as solid nitrogen fertilizers. Due to the fact that liquid nitrogen fertilizers are applied locally, the arrangement of feeding coulters must be carried out for continuous sowing crops at 20-25 cm, and in meadows and pastures - 30-35 cm, when fertilizing tilled crops - depending on the row spacing. The technology of applying liquid nitrogen fertilizers requires higher vocational training specialists, skill and responsibility of machine operators. The farms must be fully provided with a modern material and technical base for their storage, transportation and application.

Ammonia contain 30 to 50% nitrogen. Appearance is a light yellow liquid. yellow color. They are obtained by dissolving ammonium nitrate, ammonium and calcium nitrate, urea or ammonium nitrate and urea in aqueous ammonia. This is done in special installations. A hot solution of ammonium nitrate (or a mixture of calcium and ammonium nitrate) is introduced into 10-15% ammonia water, driven by a centrifugal pump, and the fertilizer is adjusted to the required composition. Transported and stored in special, hermetically sealed tanks, designed for low pressure.

Ammonia differs significantly not only in the concentration of total nitrogen, but also in the ratio of its various forms (free ammonia, bound ammonia, amide and nitrate nitrogen). Therefore, they are diverse in physical properties. Due to the large temperature range of the onset of crystallization (from +14° to -70°C), it is necessary to produce ammonia with a low crystallization temperature during storage in winter, and with a higher crystallization temperature in summer. All ammonia products are transportable, as they have a high specific gravity and nitrogen concentration.

Like all ammonium salts, especially those containing free ammonia, ammoniates cause corrosion of alloys with copper, and ammoniates with ammonium nitrate also oxidize ferrous metals. Therefore, to work with them, containers made of aluminum or its alloys are required, of stainless steel or ordinary steel tanks with a protective corrosion coating with special varnishes (epoxy resins). Containers made of polymeric materials are also used.

In terms of their effect on crop yields, ammonia in most cases is equivalent to solid nitrogen fertilizers.

UAN solutions (mixtures of aqueous solutions of urea and ammonia saltpeter) are prepared in the factory from non-evaporated melts of these fertilizers with a nitrogen content of 28-32%. CAS have a neutral or slightly alkaline reaction, they are transparent or yellowish liquids with a density of 1.26-1.33 g/cm. Due to the reduction of a number of operations in the production of UAN in comparison with solid nitrogen fertilizers (evaporation, granulation, and others), the cost of producing a unit of nitrogen is significantly reduced, and high density fertilizer solutions increases their transportability.

nitrogen for plants

Since nitrogen is a key component of amino acids, it is essential and therefore found in almost every part of the plant. This is the "glue" by which solid cell walls make the plant strong and support it. vertical position. , the pigment that absorbs light in the process, is made up of proteins bound around . Nitrogen is a component of growth-control chemicals and kinins, and is also part of the nucleoproteins, or genetic code of plants.

Nitrogen is very mobile in the plant and can move from its individual parts to those where it is most needed. A lack of nitrogen disrupts the process, causing it to stop due to poor development, as well as yellowing due to insufficient formation of chlorophyll. Plants “transfer” nitrogen from old leaves to new, young ones. And on the old lower leaves, signs of nitrogen starvation appear. On cereal crops, it is very easy to recognize nitrogen deficiency. In particular, it manifests itself very characteristically: a noticeable lightening of the whole plant and browning - first on the lower leaves, in the form of the letter V, going from the central vein to the edges of the leaf. Subsequently, the entire leaf dries up, then the leaves in the middle part of the plant begin to suffer. If the situation is not corrected, the plant may die.

Diagnose nitrogen deficiency modern methods simple enough, but often very valuable time is spent on this, and you need to respond very quickly. After all, while the plant is starving, it is under stress. Naturally, in such a state, the ongoing processes slow down and even stop, which form future harvest. So, if a lack of nitrogen manifested itself in, the formation of productive shoots stops, if in the tube phase, the plant stops the process of laying additional “floors” in the ear, that is, spikelets. Nitrogen deficiency in the phase of the flag leaf leads to the fact that additional flowers are not formed, and during earing - grains. And if nitrogen starvation occurs during the filling of grain, then the grains will be frail, unfulfilled and of poor quality.

In addition, visible signs of nitrogen starvation are already a loss of 30% of the future crop. The way out of this situation is as follows: knowing the amount of nitrogen that is necessary to create the desired crop, and how much nitrogen the plant consumes in each particular phase, it is possible to prevent possible starvation through the additional application of nitrogen fertilizers.

Nitrogen fertilizers act on the reaction of soils as follows.

1. Very acidic or strongly acidic:

Ammonium sulfate - 3 kg CaO is absorbed per 1 kg of nitrogen;

2. Relatively acidic:

Urea, ammonium nitrate nitrate. ammonia - 1 kg of CaO is absorbed per 1 kg of nitrogen.

1. Neutral or slightly acidic:

Ammonium-calcium nitrate - 0.4 CaO is absorbed per 1 kg of nitrogen.

2. Alkaline action:

calcium nitrate - 1 kg of nitrogen adds up to 1 kg of CaO;

calcium nitrate - 1.7 kg of nitrogen adds up to 1 kg of CaO.

If the soils are carbonate, then there is no need to be afraid of acidification. But if the pH tends to decrease, then in this case it is necessary to approach the choice of fertilizer carefully.

FORMS OF NITROGEN

Soil nitrogen is represented by exchangeable ammonium (NH 4 +), which is absorbed by soil colloids. This form of nitrogen is immobile in the soil and cannot be washed out of the soil profile. Therefore, it is also called "long" nitrogen. It goes through a long way of transformation in the soil into the nitrate form, and accordingly, it can “work” for a long time.

The main sources of this form of nitrogen entering the soil are the application of ammonium fertilizers and the process of ammonification (rotting) - the process of decomposition of organic compounds (proteins,) as a result of their enzymatic hydrolysis under the action of ammonifying microorganisms.

In addition to ammonium, nitrate (N0 3 -) and nitrite (N0 2 -) forms of nitrogen are present in the soil, which are in the form of soluble salts in the soil solution. This is "fast" nitrogen. It actively enters the plant through the root system and is absorbed just as quickly. Almost within a day, it can “enter” the plant and begin to create a crop. However, it is also quickly washed out of the soil. Nitrate dissolves in water, thus becoming mobile. With melt water and heavy rainfall, nitrates “float away” from the root-inhabited soil profile to deeper horizons and become inaccessible to plants.

Such a difference between these two forms of nitrogen is rather a plus in the management of nitrogen nutrition. When you need to immediately feed the plant, nitrate nitrogen is added. A vivid example of this is the early spring top dressing of winter wheat. Only nitrate can work here, since ammonium nitrogen is inefficient due to its very long conversion. After all, in early spring, temperatures are low, microorganisms are not yet working, and the process of converting ammonium into nitrate lasts about 5-6 weeks.

Or another situation: . Nitrogen is very important for this plant, but it will be especially needed when the corn enters the 3-4 leaf phase, that is, in about a month. At this time, the formation of reproductive organs begins in corn and the need for nitrogen increases sharply. In this case, when sowing, it is necessary to introduce "long" nitrogen: ammonium or amide. This form will satisfy the needs of the crop as much as possible and will not be washed out of the soil profile until the 3rd leaf appears. So, sowing corn with a norm of 100-120 kg / ha - this is the provision of plants with nitrogen almost to the stage of the end of the formation of the cob - up to 8-9 leaves. Nowadays, urea is produced with urease inhibitors (retarders), that is, the nitrification process is even slower and nitrogen is released more smoothly, gradually nourishing the culture.

There is another way to provide nitrogen nutrition to spring crops - this is the introduction of ammonium nitrogen in the fall, when the soil temperature drops below +5°C. Fertilizer is applied in autumn, binds with soil colloids and, due to the fact that microorganisms no longer work, it remains until spring in the same form. In the spring, the crop is sown, and when active temperatures occur, the ammonium becomes nitrate under the influence of microorganisms, and as a result, the plants feed on ready-made nitrogen.

WAYS TO LOSE NITROGEN

Volatilization of nitrogen from urea. Urea applied to the soil or plant residues reacts with water and is rapidly converted by the enzyme urease into ammonium and then into ammonia. Since ammonia is a gas, it escapes into the atmosphere. If ammonium is captured by soil particles, then it is retained in it and does not evaporate. Since the reaction of converting urea to ammonium is an enzymatic reaction, the rate of conversion increases accordingly with increasing temperature. Therefore, when introducing carbamide in the form of granules in the soil, it must be covered in order to avoid the loss of nitrogen in the form of volatilization.

Loss of nitrogen during leaching. Leaching is the process of washing out soluble nitrate with water. The amount of nitrogen leached out depends on soil properties and water retention capacity. Clay and loamy soils have a high water-holding capacity, unlike sandy ones. Improving the structure of the soil, enriching it with organic matter, undoubtedly, reduces the amount of leached nitrates. When macropores are created, water enters the soil by gravity, moving vertically down through the pores and spreading horizontally.

For soils with a light texture that are not capable of holding water, nitrogen fertilizer can be applied immediately before sowing or as a top dressing during the period active growth. Nitrogen application must be carried out in time to avoid washing out of the root development zone.

In areas where during the growing season the amount of rain is small, respectively, the above problem is not relevant. However, in areas with large quantity rainfall, the timing of top dressing is critical.

Denitrification is the process of loss of nitrogen from the soil by which anaerobic soil bacteria (bacteria capable of life without atmospheric oxygen) utilize nitrate oxygen (NO 3 ) to support their life processes. The process of denitrification is the conversion of a ready supply of nitrate into various forms of nitrogen that can be lost in the atmosphere. The process of denitrification can be displayed by the following scheme: 2NO 3 - "2NO 2 -" 2NO- "N 2 O-" N 2.

To reduce the potential loss of nitrogen due to denitrification, it is necessary to synchronize the time of nitrogen application with the phase of its maximum consumption.

Immobilization is the "binding" of nitrogen by microorganisms for their growth and reproduction. Such a process occurs, for example, when a significant mass of plant residues is introduced into the soil. As a result of nitrogen immobilization, its use by plants is noticeably reduced, which leads to a decrease in yield.

Through roots and leaves. Before applying fertilizers, it must be taken into account that the plant can absorb nutrients in large volumes only with the help of the root system. foliar top dressing the most effective, but this is only an auxiliary method of applying fertilizer, and not the main one.

Currently, nitrogen from fertilizers comes to plants in three forms: nitrate, ammonium and amide. Nitrate fertilizers penetrate plants faster due to their "availability", while ammonia must go through a nitrification process. Sowing fertilization for winter wheat consists of phosphorus and potash feeding. Such elements need time to pass into soluble, accessible forms, moreover, nitrogen can be ammonium or amide. At this time, the form of nitrogen is not so important: for the reason that at the time of sowing, the soil temperature is sufficient for the work of microorganisms that convert one nitrogen form to another.

In addition, nitrogen for wheat does not play the most important role in autumn. Its quantity can be no more than 20% of the total requirement. The task of the primary root system of wheat is to fix the plant in the soil. The first roots practically do not feed the plant, it feeds on the endosperm of the caryopsis. But the secondary root system is the mechanism that supplies the plant with nutrients. By the time the secondary root system is established in wheat, 30-40 days pass from sowing, and during this time the amide and ammonium forms will successfully become nitrate.

AT autumn period nitrogen is introduced only on light and slightly humus soils; after the bad (by takeaway nutrients from the soil) of the predecessor: if there is not sufficient stem density; and t when embedded in the soil a large number solo and plant residues. In all other cases, winter cereals have sufficient nitrogen for their development in autumn.

The maximum consumption of nitrogen by plants occurs during the period of their rapid growth, for example, t of winter wheat is the phase of tillering-exit into the tube. In spring, when the content of available nitrogen in the soil is almost zero, it is necessary to ensure the presence of the nitrate form of nitrogen in the soil. By applying ammonium nitrate in the tillering phase in spring, it is possible to fully compensate for the need of the crop ammonium (NH 4) form, which will continue to feed the culture. An alternative in this phase is the liquid fertilizer UAN (urea-ammonia mixture, N-28 or N-32), which includes the nitrate form, ammonium and amide.

In stressful situations (low temperatures, frosts, lack of moisture, etc.), the assimilation of elements by the root system is insufficient, and this slows down the rate of growth and development. At low temperatures, they are not fully absorbed even with the optimal amount of available macronutrient compounds and moisture in the soil. The ability of the root system to assimilate nitrogen is especially reduced. Often, the critical periods of consumption of micro and microelements in cereals occur in the phase of entering the tube-earing. Due to the intensive growth of the vegetative mass, the reserves of readily available nutrients from the soil are exhausted or their assimilation "does not keep up" with the growth rate of plants. This is especially noticeable in years with cold nights.

In such a situation, the plant can be helped by foliar (foliar) top dressing.

The degree and rate of assimilation of nutrients from fertilizers through the leaf is much higher than when assimilated from fertilizers applied to the soil. But the assimilation of elements through the leaves is limited. Leaves take up nitrogen the fastest. The urea molecule, getting on the leaf of the plant and penetrating inside, begins to work even when low temperatures because this process does not require the presence of microorganisms. Even a small amount of urea (8-10 kg a.i./ha) can force the plant to start the mechanism of yield formation. in early spring, even if the roots cannot yet feed on nitrate nitrogen from the soil. Such a "deception" forces the wheat to continue tillering and laying the ear.

Another phase responsible for the increase in yield is the flag leaf. This phase lasts only 7 days, but during this time wheat can increase its potential up to 25%. However, one condition must be met: the plants must be “fed”. The principle here is: the sooner the better. It must be either nitrate through the roots or amide through the leaves. Ammonium in this case cannot be useful due to too long conversion into an accessible form. But agronomists have only 7 days at their disposal! Spraying with a solution of urea during this period can be carried out in conjunction with fungicidal or insecticidal treatment. As soon as the agronomist determines the onset of phase 41 (the appearance of the flag leaf), there are 7 days before it ends in order to increase the yield. In this phase, additional flowers are laid in wheat, so instead of three, there can be five in the spikelet, and these are additional grains in the spike. The end of the flag leaf phase is determined by the emergence of the awns of the ear. By this time, the work on introducing the urea solution should be completed.

The next spraying should be planned already in phase 71 - when grain is being filled. At this time, a caryopsis is formed and the plant deposits reserve substances in the grain. The more it “sends for storage”, the larger the storage (in this case, the grain). It is possible to increase both its quality indicators with the help of nitrogen supplements. Again, the urea solution at this time can be combined with insecticidal treatment (against, sometimes) to get away from additional sprayer passes across the field.

If we talk about foliar feeding, then carbamide is the best nitrogen fertilizer for this purpose. It is interesting for its peculiarity of penetrating into the plant through the leaf apparatus in almost the same state, without disintegrating into ions. The introduction of a solution of urea, even in high concentrations, unlike other nitrogen fertilizers, does not cause burns in plants and contributes to an increase in the protein and gluten content in the grain.

It is advisable to combine foliar feeding with carbamide with the introduction of magnesium, trace elements and (or). As a result, the stress effect of plant protection products on cultivated plant increasing their efficiency.

It is recommended to spray the crops in cloudy weather and with good soil moisture, best in the evening or in the morning. Fertilization with carbamide can be carried out with almost all sprayings and if there are no warnings in the regulations for the use of pesticides. The addition of carbamide to the working solution increases the throughput of the leaf cuticle, which facilitates the penetration of pesticides into the plant, enhances their effectiveness, and facilitates the absorption of other nutrients through the foliage.

FEATURES OF USE OF NITROGEN FERTILIZERS

The total amount of nitrogen for the crop depends on the planned yield. That is, to calculate the need for fertilizers follows from how much big harvest planned. Knowing that for the formation of 1 ton of grain, wheat consumes 20-25 kg of nitrogen in the active substance, the total amount of nitrogen fertilizers that must be applied throughout the entire growing season of wheat is calculated. For example, if a yield of 5 t/ha is planned, in order to obtain such a yield, it is necessary to ensure the sowing of about 100 kg of nitrogen in the active substance. Of course, it is necessary to correct this amount, taking into account the presence of nitrogen in the soil of the predecessor and the previously applied fertilizers, and make a difference. It is known that during the autumn tillering before leaving for winter, winter wheat consumes no more than 20% of nitrogen from the total amount. Up to the stage of entry into the tube - 50% - before the ejection of the ear.

If you apply phosphorus, potassium in fertilizers simultaneously with sowing (for example, with ammophos or nitroammophos, which contain a small amount of ammonium nitrogen), the need for nitrogen for the autumn period is almost completely met. In addition, plants will still be able to use mineralized nitrogen from soil organic matter. The remaining 80% of nitrogen is introduced in the spring. At the same time, fractional introduction is a priority. There are several reasons for this: firstly, the rapid modification of nitrogen in the soil and, as a result, its lack; secondly, fractional application guarantees the supply of nitrogen in those phases when it is especially needed by plants. Small fractional doses of nitrogen fertilizers in each specific phase contribute to the timely supply of nitrogen to the plant and increase yields. In addition, the method of fractional nitrogen application reduces its losses to almost zero.

The optimal dose is the one at which you can get the maximum economic effect from growing a crop and the highest quality of the crop without a negative impact on environment. Depending on the method of applying certain fertilizers, the doses of these fertilizers also vary. Agricultural producers in practice have long determined what doses of nitrogen fertilizers do not harm plants, thus eliminating the possibility of losses. So. when working with liquid fertilizers, for example, UAN, the irrigation method is used, that is, in the spring, in the tillering phase, wheat is irrigated with a large drop with special nozzles at a rate of 100-120 l / ha (130-160) kg / ha. When the wheat enters the bobbing or flag leaf phase, watering is changed to spraying with a regular nozzle and a urea solution is used instead of UAN. For 150 liters of working solution, 20 kg of urea in physical weight is added. Such top dressing is always combined with the operation that is planned for wheat: be it insecticidal or fungicidal treatment.

fertilizer form. This factor is of tremendous importance in obtaining or not receiving high yield. Having the wrong form of nitrogen, not only can you waste money on purchasing and applying the wrong fertilizer, but also miss out on the benefits of using the “right” fertilizer and the opportunity to get an increase in yield from the form of nitrogen that would generate an increase in yield. Example: spreading carbamide in early spring is a mistake that will lead to crop losses. In the spring, after tillering of wheat, there is only “fast” nitrogen, and this is the nitrate form, that is, saltpeter, UAN. And here comes another rule.

Time of entry. At the time of fertilization, the crop should not need nitrogen, but should be able to use it quickly, which will minimize nitrogen losses. In other words, the culture should already wake up from hibernation, but at the same time it should not yet experience hunger. Undoubtedly, the weather and technical capabilities production workers make their own adjustments to the process of feeding the culture. But it's about how to please the crop, to help it reach its maximum yield potential. Having found opportunities for this, there will be an understanding of how to get away from adverse factors that reduce yields. Analyzing the failures, we can say with confidence that this is not always the weather, but 80% slowness, delay in processing, disorganization of the process or lack of resources.

Late means too little. Wheat, as a crop, in which the formation of the components of the crop takes place in each specific phase, there is one more rule. Knowing that it is necessary to apply nitrogen in the tillering phase, application in the tube phase is a loss of maximum benefit. Wheat will not die, but it will reduce its potential even if a large dose of nitrogen is applied. It's just that this nitrogen will not be able to do in the tube phase what it could do in the tillering phase. This simply means that, having been late for a few days, farmers not only underfeed the plant, but also lose funds for the unproductive application of fertilizer that is no longer so relevant.

ALTERNATIVE SOURCES OF NITROGEN

Since mineral nitrogen fertilizers are very expensive today, farmers are constantly looking for additional sources of nitrogen nutrition to reduce this cost item.

Perhaps the most famous way to reduce the cost of mineral nitrogen fertilizers is to introduce legumes into the crop rotation. Crops such as peas, soybeans, alfalfa, clover, sainfoin, lupins, etc. are nitrogen generators in the crop rotation. Thanks to symbiosis with nodule bacteria, they provide themselves with 75% (and some more) nitrogen. In addition, after harvesting the legume, all the nitrogen that is fixed in the nodules is mineralized and becomes available to the next crop. I call this process fertilizer from the air. After all, it is known that peas, soybeans, horse beans leave behind from 40 to 90 kg of nitrogen in the active substance per 1 ha.

The use of crops with different depths of root systems in crop rotations will also help to provide additional nitrogen nutrition. Nitrate nitrogen, which the plants did not have time to absorb, is washed out into the deeper layers of the soil. So, the alternation of crops that have a shallow root system (grain cereals), with those crops whose roots go deep (sunflower, beet), provide nutrient intake at different horizons, thereby giving the culture additional source nutrition and do not deplete the top layer.

Green manure also contributes to the enrichment of the soil with nutrients. They are sown not for harvest, but for the purpose of improving the condition of the soil, clearing weeds, and decompacting. Green manure is sown, as a rule, after harvesting the winter crop and occupy the field before leaving for the winter.

Another, unfortunately, unfamiliar assistant to agricultural producers is mycorrhiza. This is a tree fungus that spreads in the soil with the help of mycelium. He loves to settle on cereals and leguminous plants. Unfortunately, mycorrhiza does not survive with intensive machining. This is an amazing natural system, which is not only a conductor of nutrients, but also serves as a regulator water balance plants. If mycorrhiza lives on soils, then even drought is not terrible for plants!

It is also beneficial for agricultural producers to maintain the presence of a large amount of organic matter in the soil, since the higher the humus content, the more nitrogen can be mineralized. In a warm period of time, when microorganisms are active and the process of converting organic nitrogen into mineral nitrogen proceeds quickly, it can be considered that 1% of humus is equal to 15 kg of nitrate nitrogen per 1 ha. Accordingly, in 3% 45 kg a.i. nitrogen. This is a good incentive to increase the humus content in soils. If you calculate how much humus costs in monetary terms, you get interesting figure. So, 1 kg of a.i. nitrogen in terms of cost today costs about $1.4, respectively, it is $63 per hectare. If we translate this into fertilizer, it turns out that the organic matter of the soil annually lends us 170 kg of ammonium nitrate or 125 kg of urea per hectare. But it must be remembered that this resource is not unlimited. Loans must be repaid! Consumer attitude could be very costly in the future.

Plant residues are another source of nutrition. As they decompose, they release nutrients - first for microbes and saprophyte fungi, and then for plants.

Do not forget about organic fertilizers. In farms that, in addition to crop production, also have developed animal husbandry, an important source of improving the nitrogen regime of soils is the use of various types of organic fertilizers.

Nitrogen is one of the most demanded by plants chemical elements. Its lack can slow down the growth and development of most garden and horticultural crops. Plants experience the greatest need for nitrogen in the spring, at the time of their awakening and active growth. Therefore, we will start talking about using in the country with nitrogen.

Nitrogen is one of the most demanded chemical elements by plants.

Everyone has their own requirements

Not all crops equally need a high nitrogen content in the soil - this is the first thing we need to remember so that top dressing will benefit the plants, and not harm them.

First group

Under these crops, nitrogen fertilizers should be applied both before sowing (planting) and during the growing season; recommended doses - at least 25 g of ammonium nitrate per 1 sq.m of plantings (if other fertilizers are used, their amount is adjusted depending on the nitrogen content).

Cucurbits and other vegetables of the first group have a high need for nitrogen

Carbamide (urea) 89 rub LOOK
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Lime ammonium nitrate 69 rub LOOK
Russian Garden

Carbamide (Urea) (0.8kg.) (Factorial) 74 rub LOOK
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Ammonium nitrate (1kg.) 76 rub LOOK
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Urea (carbamide, carbonic acid diamide)

The most concentrated nitrogen fertilizer; is produced more often in granules. It dissolves well in water. The nitrogen content (in amide form) is not less than 46%. Plants absorb nitrogen from urea poorly - it must first be converted into a mineral form, and this process directly depends on the acidity of the soil and its temperature. The most effective use of urea for fertilizing on neutral soils in the warm season.

Urea is the most concentrated nitrogen fertilizer

The best way to use is foliar nitrogen fertilization, especially useful for fruit trees (in the spring, starting from the moment the leaves form and then every 10-12 days during May and June; the solution is prepared in the proportion of 50 g of fertilizer per 10 liters of water).

In general, urea is best applied in liquid form; when applying dry fertilizer, make sure that it is evenly distributed in the soil - a high concentration of nitrogen is fraught with burns in plants.

: Matchbox-13 g, a tablespoon -10 g, a teaspoon -3 g.

Ammonium nitrate (ammonium nitrate; ammonium nitrate)

Easily soluble in water, fast-acting fertilizer, most often produced in granules. Nitrogen content 34 - 35%. Due to the fact that nitrogen in this fertilizer is in both nitrate and ammonia form (equally), it has a universal application and can be used in almost any conditions and for any crops (some sources do not recommend applying it under cucumbers and melons). It should be borne in mind, however, that with regular use, ammonium nitrate acidifies the soil.

For reference (how to measure the right dose of fertilizer): matchbox -17 g, tablespoon -12 g, teaspoon -4 g.

Ammonium sulfate (ammonium sulphate)

Let's well dissolve in water; Available in the form of a white or grayish crystalline powder. During storage, it practically does not cake. The nitrogen content (in ammonia form) is about 21%. Most often used in the main application of fertilizers.

Suitable for light, permeable soils as the ammonia nitrogen is fixed in the soil. But keep in mind: this fertilizer strongly acidifies the soil(therefore, its use is optimal for fertilizing rhododendrons, heathers and other lovers of acidic soil). On neutral and slightly acidic soils, it is recommended to mix ammonium sulphate with lime or chalk before applying (especially in rows or planting holes) (13 g of lime per 10 g of fertilizer). But it should not be mixed with ash under any circumstances.

For reference (how to measure the right dose of fertilizer): matchbox -19 g, tablespoon -14 g, teaspoon - 5 g.

Calcium nitrate (calcium nitrate; calcium nitrate)

Easily soluble fertilizer produced in large cream-colored granules. Nitrogen content (in nitrate form) from 15 to 17%. Alkaline fertilizer, especially effective on acidic soils. It absorbs moisture very well and quickly caking, so it needs to be stored in a waterproof container. Great for liquid dressings, especially for bulbous crops; recommended for indoor use.

Calcium nitrate is especially effective on acidic soils.

Sodium nitrate (sodium nitrate; sodium nitrate)

Well soluble in water, yellowish or grayish fine crystalline powder. The nitrogen content (in nitrate form) is about 16%. Alkaline fertilizer universal application, most effective on unlimed acidic soils. It is better to use in the form of liquid dressings (in particular, for beets and potatoes). Does not cake during storage.

When using any fertilizer, do not exceed the doses and fertilizing times recommended for each crop. Do not forget that the need for nitrogen in most plants decreases in the second half of summer, and at this time the application of nitrogen fertilizers should be reduced, if not completely abandoned, so that perennial crops have time to fully prepare for the upcoming winter. But in the spring, both the garden and the vegetable garden will be grateful if you replenish the food supplies necessary for the active growth of green pets.

Yellow corn, pale sunflowers and soybeans... This pattern can often be seen in some fields. The reasons for this may be different, but one of the main ones is a lack of nitrogen. How to apply nitrogen fertilizers correctly? What are the features of introducing into the know-till technology? When is the best time to apply nitrogen fertilizers for spring crops? What are the methods and dangers? This will be discussed in this article.

QUESTION PRICE

Improper application of nitrogen fertilizers - money down the drain. And a lot of money! The use of fertilizers must be approached responsibly, especially those containing nitrogen. You should not make a decision just because “it seems to you” or “the neighbor does it”. You should understand the principles and nuances of using nitrogen fertilizers in no-till technology.

Nitrogen applied incorrectly is money thrown away.

Illiterate use of nitrogen fertilizers leads to direct financial losses, in the form of fertilizer costs and their application. The consequences can be different: washing, nitrogen starvation of plants. In the case of washing, the environment around you is polluted - nitrates get into the stakes, rivers and lakes. Losses of nitrogen as a result of washing will lead to crop shortages. And then the agronomist and the owner will wonder why the corn hasn't been harvested this year?!

Today, the issue of applying nitrogen fertilizers for spring crops is quite acute. When is the best time to submit them? In the fall, spring or just before sowing? Or fractionally - in autumn and spring? But it won’t wash with moisture, what was brought in in the fall? These questions of farmers are understandable - no one wants to spend money and not get the desired result.

To get answers to these questions, you need to understand the forms of nitrogen found in popular nitrogen fertilizers.

NITROGEN IS IMPORTANT AND MOBILE. BE CAREFUL!

FORMS OF NITROGEN

Everyone knows about three forms of nitrogen: amide NH2, ammonium NH4 and nitrate NO3. What is the difference?

The amide form is absorbed only through the leaves. In 1-4 days it turns into ammonium. If the fertilizer contains NH4 (the ammonium form of nitrogen), then the nitrogen immediately combines with the soil.

The ammonium form of nitrogen is not washed out, but is not available to plants. In order for NH4 nitrogen to become available to plants, the process of nitrification must go through, i.e. bacteria must convert it to NO3, the nitrate form of nitrogen.

It takes 7 to 40 days to convert the ammonium to the nitrate form, depending on the temperature. The process of transition from one form to another can be expressed as follows:

Only the nitrate form is absorbed by plants through root system. This form of nitrogen is absorbed immediately after application. NO3 never binds to the soil and can therefore be washed away. This is especially true on sandy soils and slopes. The nitrate form of nitrogen is available to plants and can be assimilated even at low temperatures.

THROUGH THE ROOTS, PLANTS ASSUMPTION ONLY THE NITRATE FORM OF NITROGEN

UREA, SALTPETER or CAS?

Carbamide contains one form of nitrogen - amide. As we have already noted, this form is assimilated only through the leaf surface. It may take 40-45 days to turn into an accessible nitrate form and the temperature is not lower than +5 ... + 10 ° С. In the cold season, carbamide is ineffective. The nitrogen contained in carbamide will be available to the plant only after it has been converted to the nitrate form.

Urea is not the best choice for the main nitrogen fertilizer for no-till. The amide form of nitrogen will only work for the next crop. A scavenger is also interested in the decomposition of plant residues.

Ammonium nitrate contains two forms of nitrogen - ammonium NH4 and nitrate NO3. One of them is “mobile” and can be washed, the other is fixed in the soil and gradually transforms into “mobile” and accessible. This type of fertilizer is recommended to be applied to moist soil at a temperature NOT higher than +10°С.

Saltpeter can be purchased in advance and stored on the farm. This gives unconditional efficiency for making. Saltpeter can be applied with a spreader, which gives good distribution uniformity.

UAN (carbamide-ammonia mixture) - contains all three forms of nitrogen. The nitrate form of nitrogen, which is contained in UAN, is immediately available to plants, while the other two - amide and ammonium - are gradually transformed into nitrate.

Saltpeter and UAN contain the nitrate form, which will serve as “food” for bacteria and fungi that mineralize plant residues.

It should be noted that UAN is not demanding on the conditions of application. Neither temperature nor soil moisture affects the possible “losses” of nitrogen. You can make CAS even when high temperature and dry soil.

CAS has certain restrictions during transportation and storage. UAN is an extremely corrosive liquid. Not every sprayer will pass this test. In addition, when applying, the sprayer tubes can become clogged with debris, which will negatively affect the uniformity of application.

HOW MUCH AND FOR WHAT?

Nitrogen fertilizers in the no-till technology are applied not only for the planned harvest, but also for the decomposition of plant residues.

Mineralization (decomposition) of plant residues occurs due to fungi and bacteria. These microorganisms live in the soil and on the surface. They remain active under favorable conditions: temperature +5 ... + 40 ° C and the presence of moisture. For the development of fungi and bacteria, and the maintenance of their vital activity, organic matter (plant residues) and nitrogen are needed. We have already written about how we calculate the amount of fertilizers on our farms (an excerpt from the article below).

If you do not give additional nitrogen for the decomposition of plant residues, then microorganisms will in any case consume nitrogen from the soil, which was intended for plants. If this is not taken into account when calculating the rate of nitrogen fertilizers, then the result will be a decrease in yield.

By the way, this is one of the so-called “childish mistakes” of novice scavengers. The result of this approach can be seen in the photo, which shows the border between soybeans planted on oats (right) and soybeans planted on corn (left).

When applying nitrogen fertilizers, the difference in the amount of plant residues was not taken into account.

BE AWARE OF CROP RESIDUE IN THE FIELD

WHEN TO APPLY NITROGEN FERTILIZERS?

In No-till technology, nitrogen fertilizers are applied to the soil surface. In fact, the same as in any other technology. nitrogen fertilizers for sowing spring crops can be applied both in autumn and spring. It all depends on the conditions in which the farm is located: rainfall, soil types, terrain, temperature.

In regions with adequate rainfall and sandy soils, nitrogen flushing is possible. Therefore, the application of fertilizers containing the form of NO3 is best carried out closer to sowing, i.e. during the spring period.

On flat chernozem soils, with an average annual rainfall of no more than 350 mm, nitrogen fertilizers for spring crops can be applied in late autumn. More specifically, from the end of October until the appearance of snow cover.

There is no need to apply fertilizer on snow cover. Some farmers believe that if the snow cover is insignificant (up to 5 cm), then nitrogen fertilizers can be applied. This is mistake! Even with a thin snow cover, the slightest melting of snow will cause water runoff. The water will move the nitrogen into the lowlands that each field has. This will lead to an uneven distribution of nitrogen in the field.

Sloping fields will always have flushing and flushing. And with enough rainfall, nitrogen losses are inevitable and huge!

In late autumn, as a rule, are created ideal conditions for the introduction of ammonium nitrate. The soil during this period is moist, and the air and soil temperature does not exceed +10°C. At this temperature, nitrogen does not "fly away".

In spring, the air temperature rises. Upper layer soil loses moisture. window for efficient introduction nitrogen fertilizer is extremely small. This happens not only for weather conditions, but also because during this period one more operation is superimposed in the field - winter rapeseed and wheat are being fed. Therefore, it is necessary to "catch" the frozen-thawed soil.

Thus, we have found that nitrogen fertilizers that contain two or more forms of nitrogen give the best effect. When applying, one should take into account the amount of precipitation in the region, the type of soil and the presence of slopes in the fields. The calculation of the norm must be done taking into account the amount of nitrogen necessary for the decomposition of plant residues of the predecessor crop. Granular nitrogen fertilizers are most effective when applied to moist soil.

How is nitrogen fertilizer applied on the farms of Agromir Company? Ammonium nitrate is used everywhere. In the farms of the Kirovograd region, the introduction is usually planned for autumn. There is also a spring application. Experience has shown that the timing of fertilization does not affect yield. Although, some experts believe that autumn application is preferable.

In the Zhytomyr and Ternopil regions, ammonium nitrate is spread in the spring. The reason has already been discussed above: sloping fields, heavy rainfall and sandy soils.

Understanding the rules and dependencies that have been outlined in this article will allow you to get the most out of nitrogen fertilizers.

Choose forms, calculate rates and apply nitrogen fertilizers correctly. Dark green you crops and high yields.

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