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Methods and timing of fertilizer application


Fertilization system

Critical and maximum period

Critical period is the period of plant vegetation when the lack of any element has the most negative effect on growth, and the subsequent optimization of nutrition does not fully correct this effect. The critical period of nitrogen and phosphorus nutrition for most crops falls within 10-15 days after sprouting. Lack of potassium in the first phases of plant development reduces yields, but improving potassium nutrition in subsequent phases allows to correct the negative impact.

Deficiencies in nitrogen and phosphorus are often evident in early spring, when low soil temperatures reduce the activity of microorganisms that mineralize soil organic matter.

The maximum period is the period in plant nutrition at which the average daily intake of nutrients is maximal. Most often, the maximum falls on the period of the highest growth of dry matter.

Fertilizer application methods

There are three basic methods of fertilizer application:

  • main;
  • pre-sowing (row), or pre-planting;
  • post-sowing (top dressing).

The basis for calculating the rates of fertilizers for crops are the physiological needs of plants in elements of nutrition. In the absorption of nutrients are distinguished critical and maximum periods.

Creating an optimal regime of plant nutrition during the growing season, taking into account the implementation of the potential productivity of plants in terms of quantity and quality of yield is possible with a rational combination of all methods of fertilization.

Under conditions of low moisture and arid climate the splitting of the total dose of the main fertilizer and top dressing, most often, agronomically and economically unreasonable.

According to the method of fertilizer incorporation, a distinction is made:

  • scattered;
  • local – in rows, sockets or wells;
  • local-tapered.

For soluble and soil-absorbed fertilizers, local and local-tapered are effective methods of application. The main fertilizer for crops with a row seeding method can be applied by local-taper method with special devices for plows and cultivators-ploughs. With local application the nutrients are less fixed by the soil and are more accessible to the plants, increasing their utilization factor.

Table. Influence of fertilizer application methods on consumption of main nutrition elements by spring wheat, in % of absolute dry matter weight (according to Y.V. Evtefeev, 1971)

Experience option
Phases of development
milk maturity
waxy maturity of the grain
Control (without main fertilizer)
without row fertilizer
P10 in the rows when sowing
N60P60K60 spreading under the autumn plowing
without row fertilizer
P10 in the rows when sowing
N60P60K60locally-tapered method under the autumn plowing
without row fertilizer
P10 in the rows when sowing

The uptake of nutrients by spring wheat increases with the local-tape method of application of the main fertilizer compared with the spreading method. At the same time grain yield of wheat increases by 0.05-0.11 t/ha.

Table. Effect of methods of fertilizer application on the yield of spring wheat, 1969-1970. (according to Y.V. Evtefeev, 1971)

Experience options
Yield, t/ha
Increases, t/ha
Control (plowing land without fertilizer)
Р10 in the rows when sowing
N60P60K60 in a spreading method under the autumn plowing
N60P60K60 locally-tapered method under the autumn plowing
N60P60K60 locally-tapered method under the autumn plowing + P10 in the rows when sowing

Organic fertilizers are embedded deeper into the soil, especially on light soils. In humid climates, shallow incorporation is preferred on heavy soils to accelerate mineralization. Mineral fertilizers, especially nitrogen fertilizers, are applied together with organic fertilizers to reduce nitrogen consumption from the soil humus.

Main (pre-sowing) fertilizer

The main, or pre-sowing, fertilizer is designed to meet plant nutrient needs after seedlings until the end of the growing season. For most crops under conditions of sufficient moisture or irrigated agriculture the main fertilizer accounts for 60-90% of the total dose, under conditions of insufficient moisture – 90-100%.

The main organic and phosphorus-potassium fertilizer is usually carried out in autumn, nitrogen – in spring under the pre-sowing tillage in areas of sufficient moisture or with others – in autumn under the main tillage in areas of insufficient moisture with embedding implements scattered or locally. The effectiveness of deep embedding of fertilizers before sowing increases with increasing soil moisture deficit and aridity of the climate.

The main (pre-sowing) fertilizer is embedded with the plow during autumn plowing. Before sowing of any crop and during the growing season plants must be provided with a certain amount of nutrients in each period. This is achieved by mobilizing the natural fertility of the soil, or by fertilizing.

The correct ratio of nutrients is important, and its violation makes it difficult for the plant to use them. For example, the lack of phosphorus causes excessive accumulation of nitrate nitrogen in plants. The combined application of phosphorous and nitrogen fertilizers normalizes the nitrate nitrogen content in plants. The optimal ratio of nutrients affects their arrival in the plant, the direction of the synthesis of organic compounds, the growth and formation of yield and product quality.

Even J. Liebich noted that fertilizers work most favorably if they are used to establish the correct ratio of nutrients in the soil. This was also pointed out by D.N. Pryanishnikov, who wrote that the effect of phosphorus fertilizers depends on the provision of plants with other elements, primarily nitrogen.

Before sowing, most of the total dose of fertilizer provided for the crop is usually applied.

Timing of the main fertilizer and method of embedding are determined by climatic conditions of the zone, the properties of soil and fertilizers, and biological characteristics of crops. For example, in the forest-steppe of European Russia, where the best moisture conditions, 60-70% of the total dose of fertilizers is used in the main application, the rest is applied in rows at sowing and in top dressing. For row crops in this zone, deep autumn plowing of fertilizers has an advantage over spring plowing during the cultivation of the autumn tillage.

In the zone of sod-podzolic soils with sufficient moisture and irrigation, the fertilization system of crops consists of three methods: the main, pre-sowing and top dressing. In this zone, about 50% of the total rate is applied before sowing.

In the zone of sufficient moisture, on heavy waterlogged soils, re-tillage of autumn plowing is usually carried out in spring. This is done when preparing the soil for row crops with a well-developed root system. In this case, the fertilizer is applied in spring when plowing the tilled soil in autumn. In these conditions, the high efficiency of fertilizers is observed when they are applied in the spring before sowing with subsequent embedding by the cultivator.

Cultivation of fertilizers applied before sowing is also acceptable in the forest-steppe for winter cereals. Here, during harvesting of late fallow-occupying crops and when there is a lack of moisture to avoid drying out the soil is limited to surface pre-sowing tillage, such as discing, cultivation, deep discing. In this case, the fertilizer intended for the main reception, applied after harvesting of the winter predecessors.

The choice of optimal timing of application is determined by the properties of the soil, especially granulometric composition. Thus, on light soils and with sufficient moisture most of the nutrients, especially nitrogen, will migrate along the soil profile outside the root layer. Therefore, embedding, especially nitrogen fertilizers, is carried out in spring.

In determining the timing and method of application of fertilizers are also based on the properties of the fertilizer itself. Phosphate fertilizers are well absorbed by the soil at the point of application, phosphorus little migrates along the soil profile, quickly fixed by the chemical absorption, especially on soils with high absorption capacity and the degree of saturation of the bases. Danger of phosphorus leaching on such soils is almost absent. Potassium is well kept by soil, except for light soils with low absorption capacity. Nitrogen fertilizers are the most mobile.

Almost all agricultural regions of Russia noted the effect of phosphorus, and often potassium fertilizers with the fall with the subsequent incorporation of the plow when plowing the soil tilled in autumn. Nitrogen fertilizers in areas of sufficient moisture, especially on light soils, is made in spring with subsequent incorporation of the plow when plowing the soil tilled in autumn, or cultivator. For winter cereals, a portion of nitrogen fertilizer is applied before sowing to create optimal conditions for development in the fall.

When applying nitrogen fertilizers, take into account the characteristics of crops. For example, under row crops with a well-developed root system, the best effect is achieved by deep embedding the fertilizer. Also take into account the form of fertilizers. Thus, ammonia forms of nitrogen fertilizer fertilizers made and from autumn, as ammonium is well retained by soil. Nitrate nitrogen is not adsorbed by the soil, so it moves with the soil solution. Therefore, the application of nitrate forms of nitrogen fertilizer in autumn with sufficient moisture, especially on light soils leads to significant losses of nitrogen.

Potassium fertilizers often contain a large amount of ballast elements, so the introduction of chlorine fertilizers under the culture, negatively reacting to chlorine, leads to a decrease in yield and quality problems. If it is necessary to apply chlorine-containing potash fertilizers, they are applied in autumn under autumn plowing. In this case, chlorine poorly adsorbed by the soil is washed into the underlying layers and does not have a negative effect on the yield. It is especially inadmissible to apply chloride-containing potash fertilizers to chlorophobic crops during the growing season.

Local application of the main fertilizer – by tapes, cords on the bottom of the furrow – is effective. With these methods fertilizers are not mixed with soil, are closer to the feeding part of the root system and are used by plants more effectively. Increased efficiency from the tape application of fertilizers associated with the localization of phosphate fertilizers. With this method phosphate fertilizers have less contact with the soil, resulting in water-soluble calcium phosphates are less converted to hard-soluble forms and are more fully assimilated by plants.

Local application of the main mineral fertilizer has a positive effect on the growth and physiological state of leaves, causes increased water retention capacity, increases the productivity of photosynthesis.

The advantage of the local method of fertilizer application is a higher coefficient of fertilizer use compared to the spreading method. The fertilizer dose with local application can be reduced by 30-50% compared to the spreading method.

Table. Comparative assessment of methods of fertilizer application[1]Agrochemistry. Textbook / V.G. Mineev, V.G. Sychev, G.P. Gamzikov et al; ed. by V.G. Mineev. - M.: Publishing house of the All-Russian Scientific Research Institute named after D.N. Pryanishnikov, … Continue reading

Yield, 100 kg/ha
Increase from localization, 100 kg/ha
without fertilizer
when fertilizing
Black Earths
Sod-podzolic loamy soils
Sod-podzolic sandy loam and sandy soils

More promising is a two-layer local fertilizer application before sowing crops.

Two-layer local application provides an intensive supply of nutrients during the entire growing season, which increases the effectiveness of this technique before both scattered and local application of fertilizers in one layer.

Table. Effectiveness of two-layer local application of mineral fertilizers

Yields without fertilizer, 100 kg/ha
Increase, 100 kg/ha from fertilizers applied
locally in 1 layer
locally in 2 layers
Winter rye
Winter wheat
Sugar beet

Spreading is less effective, but has been used in Russia for decades. The basic fertilizer is applied by scattered mix seeders, spreaders of mineral fertilizers and aerial spreaders.

Depending on natural and economic conditions, the main (pre-sowing) fertilizer is applied annually to each crop, sometimes, for example, under spring cereals with undersowing of perennial grasses – immediately under the cover crops contribute a total dose of phosphorus, sometimes combined with potassium, for her and the cultivated grasses of one or two years. This method is called a periodic, or reserve, application. This technique includes phosphoritization of soils, application of organic fertilizers, or special application to one annual crop of a dose calculated for three crops at once.

Numerous experiments comparing the equivalent doses in different soil and climatic zones show that the periodic (once every 3 years) application of phosphate fertilizers for annual crops is usually more effective than the annual. Under perennial forage and fruit crops, this method is even more effective.

When making the main fertilizer in the calculated rates for cereal crops efficiency row method of application is reduced. For example, rowwise application of granulated superphosphate at a dose of 10 kg/ha against the background of the main fertilizer N60P60K60 did not provide a significant increase on the leached chernozem of the experimental field of the Altai Agrarian University.

Pre-sowing (row fertilization) or pre-planting fertilizer

The pre-sowing (row fertilizer) or pre-planting fertilizer is designed to meet plant nutrient requirements during the period from germination to the appearance of full seedlings. As a rule, it does not exceed 2-10% of the total dose. Water-soluble phosphorus, less often phosphorus-nitrogen or phosphorus-nitrogen-potassium fertilizers are used more often.

It is a local most effective way of application simultaneously with the sowing of seeds in the form of a string (strip) under them or on the side at a distance of 2-3 cm. It is also called the first mandatory method of fertilizing under all crops in all soil and climate zones. Doses of fertilizers in any method of application, especially in row application, should be optimal, since the increased concentration of soil solution and osmotic pressure can lead to thinning, and in excess to the death of crops and reduce overall productivity.

Table. Optimal and maximum doses (kg/ha a.s.) and composition of pre-sowing fertilizer of main crops in the Non-Black Soil zone of Russia[2]Yagodin B.A., Zhukov Y.P., Kobzarenko V.I. Agrochemistry / Edited by B.A. Yagodin. - Moscow: Kolos, 2002. - 584 p.: ill.

Optimal doses
Maximum doses
P20, N10P20
Р10, N10P10
P20, N15P15
Р10, N10P10
P15, N10P15
Р7, N3P7
P10, N5P10
Р20, N20P20
P30, N30P30
Beets (all types)
P10, N10P10, N10P10K10
P15, N15P15, N15P15K15

The main task of pre-sowing fertilization is to improve root nutrition in the first period of plant life. This method was developed in Russia by A.E. Zaykevich in 1880. For the first time fertilizers were introduced into the rows during the cultivation of sugar beets; later superphosphate was used for sowing cereals and other crops. Currently, there are special combined seeders for simultaneous sowing of seeds and fertilizer. In this method, fertilizer can be applied directly into the wells when planting potatoes or seedlings. This method uses small doses of fertiliser.

When fertilising with a combination drill, the seeds are separated from the fertiliser by a layer of soil. During germination, seeds and young seedlings, which are very sensitive to high salt concentrations, do not come into contact with fertiliser. This sensitivity is usually higher in small-seeded plants.

Providing plants with nutrients during the first period of life is important for later development. As young plants are particularly sensitive to nutrient deficiencies. Row or nest fertilization during sowing creates favorable nutritional conditions for the young plants, so they grow faster and more easily tolerate adverse conditions.

Favorable nutritional conditions at the beginning of growth allow young plants in a shorter time to develop a strong root system, which makes it possible to better use the nutrients of the soil and the main fertilizer in the future.

There is an increased need of plants for phosphorus fertilizers in the early period of vegetation, which is associated with the participation of phosphorus in the processes of synthesis and hydrolysis of carbohydrates. The breakdown of stored polysaccharides into monosaccharides is due to phosphorolysis. Phosphorous fertilizers introduced into rows with seeds contribute to economical expenditure of plastic substances of seeds due to slower hydrolysis of starch and reduced activity of oxidative enzymes. When assimilating apparatus appears in plants, phosphorus leads to increased hydrolysis of starch of seed, which is spent on growth processes more effectively.

Under the influence of nitrogen, starch hydrolysis, respiration rate and activity of oxidative enzymes increase, which leads to premature consumption of plastic substances of the seed. To eliminate the negative effect of nitrogen on the transformation of substances in the seed before the formation of photosynthetic apparatus, some isolation of fertilizer nitrogen from the seed is necessary. Count on the sustained positive effect of row application of nitrogen fertilizers close to the seeds can be expected only for non-acidic soils saturated with calcium, sufficiently supplied with phosphorus available to the plant and in need of nitrogen, as well as for plants with seeds with large reserves of carbohydrates (wheat, oats, barley).

Nitrogen application in nutrient solution significantly increases the phosphorus content in nitrogen fractions of organophosphorus compounds, primarily in the nucleoprotein fraction – substances that play a role in the differentiation of meristematic tissues, that is, the ways of effective fertilizer impact on the form-forming processes in plants.

Violation of the optimal ratio of nitrogen and phosphorus at the beginning of growth leads to disruption of the synthesis of amino acids, nucleoproteins, which determine the initial growth of plants. Therefore, on soils poor in nitrogen, it is proposed to apply small doses of nitrogen at sowing in conjunction with phosphorus fertilizer. On soils with low fertility and low nitrogen content it is recommended to make during sowing in addition to phosphorus-potassium fertilizer and nitrogen fertilizer in the dosage of 5-10 kg/ha of nitrogen.

As pre-sowing fertilizer is recommended ammophos, nitrophoska. High efficiency of pre-sowing fertilizer is confirmed by numerous data obtained in different regions of Russia and abroad. There is also a high payback of fertilizers made in the rows during sowing.

The composition of fertilizers applied by row and their effectiveness is determined by the biological characteristics of crops, agrochemical properties and soil fertility, the properties and forms of fertilizers, prefertilization of fields. There is a high effect of granulated superphosphate introduced into the rows during sowing. This is due to the increased need of crops in phosphorus at the beginning of the growing season and, thanks to granulation and topical application, the processes of retrogradation of phosphoric acid superphosphate proceeds slower due to less contact with the soil absorbing complex. Due to the water-soluble form of P2O5 in superphosphate and its proximity to the root system, it is actively used by plants. The utilization rate of P2O5 superphosphate at local application is 2-3 times higher than at scattered application. Phosphorus improves the development of the root system, thereby increasing the resistance of plants to drought and other adverse conditions.

Table. Comparative effectiveness of granulated superphosphate when applied in rows and scattered under the cultivator[3]Agrochemistry. Textbook / V.G. Mineev, V.G. Sychev, G.P. Gamzikov, etc.; ed. by V.G. Mineev. - M.: Publishing house of the All-Russian Scientific Research Institute named after D.N. Pryanishnikov, … Continue reading

Dosa P2O5, kg/ha
Yield increase, 100 kg/ha, with granulated superphosphate
Increase in grain yield, in kg per 1 kg P2O5, when contributing:
under the cultivator
in row
under the cultivator
in row
under the cultivator
in row

Pre-sowing (row fertilizer) fertilizer during sowing of cereals, in the wells (sockets) during planting of vegetable crops is applied locally, which increases the rate of use of nutrients. Doses of row fertilizer – 5-10 kg of nitrogen, phosphorus and potassium per 1 ha.

With row fertilization the most effective phosphate fertilizers – granulated superphosphate, ammophos. On soils with a low content of available phosphorus row fertilizer superphosphate is carried out at a dose of 10 kg a.s./ha, which provides an increase in grain yield of spring wheat by 0.26 t / ha.

Post-sowing fertilizer (top dressing)

Post-sowing fertilization, or top dressing, is used to obtain a high yield and improve its quality. The technique allows to strengthen plant nutrition in certain periods of development, complements or improves the effect of the main fertilizer. The combination of these methods can provide optimal nutrition of plants during the growing season. Fertilizing accounts for 20-30% of the total dose.

Fertilizing is carried out on the surface, embedded in the soil, scattered and local, dry and liquid fertilizers, root and foliar. Fertilizing with nitrogen fertilizers is necessary for winter cereals and perennial grasses.

Fertilizing is especially important on soils of light granulometric composition, in areas with sufficient moisture. Thus, when cultivating winter cereals and row crops on sod-podzolic soil and in the northern forest-steppe, top dressing on sandy loam soils with low absorption capacity, which require fractional fertilizer application, is effective. Application of the full rate of fertilizers in these areas in the main reception leads to large losses of nutrients by leaching from the root layer, reducing the effectiveness of fertilizers and increasing the negative impact on the environment.

Sometimes there are conditions for feeding row crops in areas with insufficient moisture: with sufficient soil moisture during the spring-summer vegetation and insufficient fertilizer application in the main reception. Fertilizing can be carried out superficially on the soil, in the soil during the vegetation of plants, and foliar, in which the fertilizer solution is applied directly to the vegetative parts of plants.

Surface dressing is used mainly for crops of continuous sowing. For example, an effective technique for winter wheat is early spring top dressing. Fertilizers are applied by fertilizer machines – by ground method or specially adapted for this purpose planes and helicopters.

Fertilization of row crops such as sugar beet, cotton, corn and potatoes is widely used. Fertilizers are applied by plant fertilizers or special devices for inter-row cultivation tools.

On the efficiency of top dressing affect natural conditions, moisture during the growing season, soil fertility and granulometric composition, biological characteristics of crops, properties of fertilizers, conditions of agrotechnics.

The efficiency of fertilizing depends on the type and forms of fertilizers. Phosphate fertilizers full rate is often made in the main reception before sowing, which as a result of chemical fixation, almost not lost from the soil. Also there is no significant loss of potassium when using potassium fertilizers in the main application, with the exception of light soils and sufficient moisture. Therefore, most of the dose of these fertilizers is applied before sowing.

The most mobile – nitrogen fertilizers, as all forms of nitrogen in good moisture and optimal temperature as a result of nitrification converted to nitrate form, which is not bound to the soil and migrates through the profile with moisture. Therefore, the full application of nitrogen fertilizer before sowing in winter can lead to significant losses of nitrogen with melt water.

Feeding of winter cereals and row crops is primarily carried out with nitrogen fertilizers in nitrate forms, which quickly migrate with soil moisture and reach the active absorbing part of the root system.

Many crops by their biological peculiarities cannot tolerate high concentration of salts, especially at the beginning of vegetation. Therefore, the application of increased doses of mineral fertilizers before sowing can have a negative impact on initial development, and in subsequent periods, increased amounts of nutrients are required. Therefore, feeding allows you to regulate plant nutrition by growth phases.

The effect of feeding is determined by the application of a set of agricultural techniques. Thus, under irrigation of cereal crops, top dressing is a method of increasing yield and improving grain quality. In areas of old irrigated agriculture when cultivating cotton, application of full dose of nitrogen before sowing always leads to lower results than application in several methods. This is explained by the fact that during irrigation nitrogen fertilizers migrate with irrigation water along the soil profile, and in spring with rising water currents they rise to the surface and concentrate in the upper layers, where there is almost no root system.

Late foliar top dressing of crops is carried out with fertilizer solutions. Late foliar fertilization has the greatest practical importance for increasing grain protein content and improving other indicators of wheat quality.

The best fertilizer for foliar feeding of wheat is urea, which gets on the leaf surface and is directly used by wheat for protein synthesis, which explains the positive effect of foliar feeding of wheat with urea during spike emergence and flowering. At the beginning of milk ripeness grain contains up to 40-50% of all the nitrogen at full grain ripeness, at the beginning of wax ripeness – up to 80%, the rest of the nitrogen goes to the grain at wax ripeness. Application of nitrogen fertilizers in the period of milk ripening increases the nitrogen content in grain and increases the yield.

The positive effect of urea is explained by the fact that it is a source of nitrogen nutrition and physiologically active substance, activates the processes of nitrogen metabolism, in particular the formation of sulfhydryl groups of amino acids methionine, cysteine and tripeptide glutathione. Amino acids containing SH-groups are involved in the processes of metabolism, growth and the formation of reproductive organs. Urea also affects the water regime of plants: late nitrogen fertilization increases hydration of colloids by increasing the total amount of nitrogen, water-soluble and non-extractable proteins. The amount of firmly bound water also increases and the water-holding capacity of leaves increases.

The mechanism of mineral uptake by leaves is similar to that of roots. The first step in the absorption of ions from the solution is exchange adsorption – the process proceeds very quickly on the absorbing surface. In roots and leaves, the absorption of salts from a solution depends on the pH of the medium, solution concentration, salt composition, duration of contact of the solution with the absorbing surface, and the age of the absorbing organ.

In a plant, there is a relationship between all vital processes, including root and foliar nutrition. Therefore, foliar fertilization increases, under certain conditions, the efficiency of fertilizers applied to the soil and the efficiency of soil fertility use. The link in this case is photosynthesis.

A foliar top dressing, increasing the intensity of photosynthesis, provides an influx of organic matter and energy material to the roots, which leads to increased respiration, rapid growth of roots, increasing their absorptive surface, which in turn leads to increased absorption of minerals. On the other hand, inflow of nutrients to leaves results in binding and retention of photosynthesis products at the place of their formation, which should have a negative effect on root activity and lead to a decrease in yield. Negative effect of foliar fertilizer on plant productivity is usually observed when it is used in the first half of the growing season, when synthetic processes prevail. A positive effect, especially on the quality of yield, appears when foliar dressing is carried out after flowering, in the period of predominance of hydrolysis processes.

The presence of an increased amount of sugars in plants after flowering allows more intensive absorption of nitrogen applied to the leaves, without compromising nitrogen absorption by the roots. Considering that by this period the absorptive activity of the roots decreases, the competition for sugars as a product of photosynthesis between the leaves and the roots is weaker. Nitrogen that entered through the leaves is well distributed throughout the plant. Normal distribution of phosphorus between the parts of the plant is possible when it comes through the roots.

Nitrogen top dressing of wheat during spike formation and flowering is an additional application in the fertilization system, but does not exclude the main fertilization, late autumn and early spring fertilization.

Yield increase from foliar fertilizing of winter wheat with urea occurs due to increase of absolute grain weight. foliar feeding provides an increase in grain yield by 150-300 kg/ha. Foliar top dressing of wheat with urea at the phases of spike formation, flowering and the beginning of milk ripening increases the protein content of grain by 1.5-2%. When foliar top dressing of sugar beet before harvesting with phosphorus-potassium fertilizer the yield increased by 10%, sugar content – by 1%.

Foliar top dressing of winter wheat with urea solution is carried out with the help of aircraft. The concentration of the solution in this case can be brought to 30%. Superphosphate solution in a 1:4 ratio, with a concentration of P2O5 about 5%, is prepared for 1-2 days because of the slow dissolution, with periodic shaking. Potassium salts are well soluble in water, so their solutions can be prepared the day before spraying. The concentration of potassium chloride solution is 3%, or 25-30 kg of potassium chloride per 800 liters of water. When spraying from an airplane, the flight altitude should be about 5 m. The AN-2 aircraft capacity is 8-10 ha per flying hour or 50-70 ha per working day; the solution consumption is 800 l/ha.

Post-sowing fertilization is effective in conditions:

  • Early spring feeding of winter crops and perennial grasses with nitrogen fertilizers at a dose of 30 kg a.s./ha. For top dressing ammonium nitrate, ammonium sulfate, urea are used.
  • Row crops top dressing with nitrogen and potassium fertilizers on light soils in the conditions of sufficient moisture and irrigation. Dose of fertilizers in the top dressing N – 30-40 kg/ha, K2O – 30 kg/ha.
  • At high calculated rates of fertilizers for crops sensitive to high concentrations of salts in the soil solution.
  • On long-term cultivated hayfields and pastures. When high estimated rates of fertilizers and applying them in one go increases the content of nitrogen and potassium in the pasture forage, which leads to animal disease. Therefore, the calculated rate is divided into several doses and applied fractionally after each mowing or grazing cycle.
  • Nitrogen foliar fertilizing of winter and spring wheat according to the results of plant diagnostics during earing – milky ripeness to increase protein content and gluten quality in grain.


Yagodin B.A., Zhukov Y.P., Kobzarenko V.I. Agrochemistry / Edited by B.A. Yagodin. – Moscow: Kolos, 2002. – 584 p.: ill.

Agrochemistry. Textbook / V.G. Mineev, V.G. Sychev, G.P. Gamzikov et al. – M.: Publishing house of the All-Russian Scientific Research Institute named after D.N. Pryanishnikov, 2017. – 854 с.

Fundamentals of Agronomy: Tutorial/Y.V. Evtefeev, G.M. Kazantsev. – M.: FORUM, 2013. – 368 p.: ill.