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Zonal peculiarities of fertilizer systems

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Fertilization system

Sod-podzolic and gray forest soils

Soils of the Non-Black Soil zone are characterized by low natural fertility: acidic reaction, low content of organic matter, low provision with nutrients. On such soils the liming of acidic soils, the maximum use of organic fertilizers, the application of high rates of mineral fertilizers is of great importance.

The need for liming, the amount of applied mineral and organic fertilizers, their distribution between crops is decided taking into account the following factors:

  • soil conditions – soil type, granulometric composition, acidity, content of mobile nutrients;
  • type of crop rotation – field, forage, specialized, grassland, vegetable;
  • availability of organic fertilizers;
  • necessary assortment of mineral fertilizers;
  • availability of lime fertilizers;
  • level of agrotechnics;
  • availability of high-yielding varieties;
  • levels of planned yields.

Fertilizer systems should provide for growth of crop yields, improvement of the quality of plant products from one rotation to another.

The development of the fertilizer system in the rotation in the Non-Chernozem zone begins with the determination of the place of liming and the dose of lime fertilizers. Liming should precede the application of fertilizers.

The effectiveness of organic fertilizers in the rotation increases with:

  • their application under row crops;
  • under a cover crop with grasses in rotations with perennial legume-grass, the impact of organic fertilizers will have a better effect on subsequent crops;
  • in combination with mineral fertilizers on humus-poor soils of light granulometric composition.

In crop rotations for livestock complexes of industrial type, which accumulate a sufficient amount of litter-free manure, this fertilizer is applied in the main reception and fertilization of perennial grasses. Mineral fertilizers are applied in optimal doses primarily for industrial crops, potatoes, cereals, cultural meadows and pastures. Increasing doses of mineral fertilizers is advisable primarily on soils with adjusted water regime, limestone or not requiring liming, as well as on soils cleared of stones, shrubs, weeds.

Basic fertilizer

The system of fertilization of individual crops in the rotation in the Non-Black Soil Zone includes the main fertilization, pre-sowing and top dressing. Organic fertilizers, lime, phosphorus and potassium fertilizers are applied to the basic fertilizer under autumn plowing. When cultivating spring grain and row crops nitrogen fertilizer is made in spring during cultivation, and for winter crops – in top dressing. When using high rates of nitrogen fertilizer (90-120 kg/ha) on loamy soils, 1/3 of the norm is made under the autumn plowing. Fertilizer applied in spring also refers to the basic fertilizer.

It is especially important to determine rates of nitrogen fertilizers for winter and spring crops, under the cover of which leguminous grasses are sown. Strong grass stand of cereals and high grain yields of the cover crop worsen the conditions of water and nutrient regimes of grasses, as well as solar insolation, which weakens their growth, leads to thinning and reduction of yields. In the Non-Black Soil Zone high rates of nitrogen more than 90 kg/ha in a single application or intake are inexpedient. Fractional application increases the coefficient of utilization of nitrogen fertilizers, their efficiency and improves the quality of agricultural products.

On sandy and sandy loam soils nitrogen fertilizers for spring cereals and row crops are applied only in spring. For winter crops on all types of soils, 1/3 of nitrogen fertilizer rate (30-40 kg / ha) is applied before sowing. When winter crops are placed in the rotation after leguminous crops and leguminous grasses, applying nitrogen before sowing often does not lead to positive results.

If the farm has a sufficient amount of phosphorus-potassium fertilizers in the fertilizer system can provide application under perennial grasses “in reserve”, ie for 3-4 years, as phosphorus and potassium are well fixed in the soil and with a surface application of fertilizer is less effective. This is especially true for phosphate meal.

Pre-sowing fertilization

Pre-sowing fertilization is provided for the introduction of granulated superphosphate, ammophos, nitrophos and other complex fertilizers into the rows when sowing spring and winter crops. On well fertilized soils, the effectiveness of this technique is reduced, but remains advisable, as fertilizer, made at sowing, contribute to good sprouts, strengthening of tillering and overwintering of winter crops.

Top dressing

Top dressing with nitrogen fertilizers is provided first of all for winter crops, which after the overwintering come out weakened and need nitrogen in the first place. Topping with phosphorus-potassium fertilizers is carried out when the crop received an insufficient amount of these fertilizers at the basic application. Nitrogen fertilization of perennial grasses with a large share of legumes is inexpedient. As the share of legumes in grass mixture decreases below 50%, which happens in the second year of grasses use, spring fertilizing with nitrogen N40-60 is provided.

In rotations with flax, a full mineral fertilizer is applied to this crop, but the rate of nitrogen is much lower than that of phosphorus and potassium. Excessive nitrogen leads to lodging of flax and worsens the quality of flax fiber. It is especially important when flax is placed after high-yield perennial grasses with clover predominance. In this case the rate of nitrogen should not be more than 30 kg/ha. After other predecessors, including one year after grasses, the nitrogen dose is not more than 40-60 kg/ha. On cultivated soils where there is a risk of lodging flax, sowing flax after clover with a hay yield of 5 t/ha will not provide a good quality crop. In this case, flax should be sown after one year or to other predecessors.

In crop rotations on sandy and sandy loam soils, a large proportion is sowing leguminous crops: lupine for fodder and grain, green manure, as well as seradella. These plants have good nitrogen-fixing ability and need phosphorus-potassium fertilizer. On the effectiveness of macrofertilizer, especially at higher doses, affects the provision of micronutrients.

The fertilization system of crops grown on the peat-bog soils with high productivity, based on the use of soil nitrogen reserves and the introduction of phosphorus and potash fertilizers. Nitrogen fertilizers are used to fertilize winter cereals and perennial grasses, especially on the less powerful poorly cultivated peat-bog soils.

Zone of black earth (chernozems) and chestnut soils

The zone of chernozems and chestnut soils occupies a vast territory of Russia (Central Black Earth zone, North Caucasus, Volga region), Ukraine and Kazakhstan (Northern, Southern and South-Eastern Kazakhstan). When considering the scientific basis of fertilizer systems this zone is divided into two parts: forest-steppe and steppe. These sub-zones differ in soil and climatic conditions, specialization of crop production, provision with mineral fertilizers.

Forest-steppe areas

Due to the shortage of mineral fertilizers in the forest-steppe areas, they are applied mainly under technical crops, potatoes, forage crops and partially under grain crops. The balance of nutrients in agriculture is characterized by a high deficit, which leads to a decrease in potential fertility, losses of organic matter, deterioration of water-physical properties of soil.

When distributing fertilizers in crop rotation optimal rates are applied to sugar beets, sunflowers, potatoes, corn for grain and silage, winter crops, fodder crops under irrigation. Spring cereals, leguminous crops and cereals are cultivated on fertilized preceding crops at the expense of fertilizer aftereffects. Under these crops directly applied pre-sowing phosphate fertilizer (P10-15).

In the year of application, plants use 20-25% of phosphorus, 50-60% of nitrogen and potassium from mineral fertilizers; 20-30% of nitrogen, 30-40% of phosphorus, 60-70% of potassium from manure.

Taking into account the after-effect of manure, which in this subzone is stronger than in the Non-Black Soil Zone, in the 9-11-field crop rotations, it is applied twice per rotation, in the 6-7-field – once. More fractional application of manure per rotation does not give advantages. The best place for the application of manure in the rotation is the precursor of winter crops and directly under the winter crops, if the crop is harvested early. Good results are obtained by applying manure for potatoes, vegetable crops, corn for grain and silage.

In forest-steppe field crop rotations, manure is applied in rates: under winter wheat and rye – 20-30 t/ha; under corn, sugar beets and potatoes – 30-40 t/ha. In areas with sufficient moisture, peat and other composts are used in addition to manure.

Soil-protective crop rotations on slopes allow for cultivation of perennial grasses for at least 3-4 years; therefore, in order to guarantee a high yield of grasses, increased doses of manure, 40-60 t/ha, are applied 1-2 years before sowing winter wheat or corn.

In the forest-steppe areas of the Black Earth region the role of the main fertilizer increases. In this reception make at least 2/3 of the annual dose of fertilizer under autumn plowing in the non-drying layers of soil. In areas of sufficient and excessive moisture nitrogen fertilizer for autumn plowing is not made, they are used in the spring for pre-sowing cultivation and top dressing.

In areas bordering Polesie, on soils with light granulometric composition and in areas with a close groundwater table under the autumn plowing all types of nitrate is not made to prevent leaching of nitrogen in the winter in the lower layers. In this subzone under the plowing is preferable to make ammonium forms of fertilizers.

Phosphorus-potassium fertilizers in all areas of the forest-steppe is preferable to make under the plowing. Phosphate flour and phosphate slag is made only under the plowing and in the first place on acidic soils, such as gray forest, podzolized and leached chernozems. Crop rotation crops that have not received basic fertilizer, sow with pre-sowing application of superphosphate or compound fertilizer.

Crop feeding is carried out only with nitrogen fertilizers in the recommended doses and at the optimum time for the crop. Nitrogen fertilizers are especially effective for winter crops in fallow and non-fallow preceding crops.

In the forest-steppe areas there is a wide variety of soils: from gray forest and podzolized black earth in the north to the typical carbonate in the south. In the northern part there is more moisture, so nitrates accumulate less. In addition, they are more washed out in the winter, so in these soils in the fertilizer system is dominated by nitrogen, which is often in the first minimum.

Carbonate and typical chernozems of this subzone have good water-physical properties and have an increased nitrification capacity. Nitrates formed during summer period, as a rule, are not washed out from root layer. Carbonate soils makes reserves of phosphorus less mobile, so phosphorus fertilizers are effective. Provision with potassium of these soils is good enough, but potassium fertilizers in the northern forest-steppe are effective.

On carbonate chernozems because of their slightly alkaline reaction more effective physiologically acidic fertilizers. In the system of fertilizing crops for podzolized soils and highly leached chernozems once a rotation rotation provide lime treatment. The best place to apply lime fertilizer is a field where sugar beets, winter after fallow or leguminous crops. Defecation mud, a waste product of sugar beet production, is best suited as liming material.

On saline soils once every 8-10 years, gypsum is applied under sugar beet or winter wheat, preceding it or peas.

In forest-steppe areas the effect of microfertilizers, such as boron on sugar beets and molybdenum on legumes and legume crops is often manifested.

Steppe areas

The soils of the steppe regions are also diverse, ranging from typical and common chernozems in the north to southern and Azov chernozems in the south. Carbonate soils are often found in these areas. Chestnut soils are common in the eastern areas, where the steppe transitions to dry steppe. Steppe areas are located in the south of the Central Black Earth zone, in the north of the North Caucasus and the Volga region, in Kazakhstan – Northern, Southern and Southeastern regions.

In the fertilization system of crop rotations should be dominated by the basic fertilizer, which is introduced in autumn under the plowing. This method eliminates the possibility of washing away and wind drift of fertilizers, as well as gaseous losses of nitrogen. In this case, the fertilizer is placed in the wetter soil layers. A single application of fertilizer in autumn is often more effective than applying the same rate in several applications.

In the steppe regions moisture availability is a factor limiting the yield and fertilizer efficiency, so all measures aimed at accumulation and preservation of soil moisture contribute to improving the effectiveness of fertilizers. In turn, fertilizers contribute to a more economical use of moisture to create yields. Water consumption for the creation of a unit of dry matter on a fertilized background decreases by 15-20%.

In steppe areas, phosphorus is often at a minimum. Phosphorus starvation of plants is a factor limiting the yield of crops. Improvement of soil phosphorus supply is achieved by applying phosphorus fertilizers. The maximum yield is achieved with the application of nitrogen, potassium and phosphorus, with the predominance of the latter.

The main method of applying fertilizers is to apply them in autumn under autumn plowing. In this method up to 85-90% of the annual rate of fertilizers for the crop is applied. The rest, mainly phosphorus, is applied in the rows during sowing. Fertilizers are ineffective, with the exception of nitrogen top dressing of winter crops.

When developing a system of fertilizers in the rotation on rainfed soils in determining the location of the main fertilizer take into account:

  • application of fertilizers in fractional rates under most crops of the rotation is not always rational;
  • high after-effect, especially of phosphorus and potassium fertilizers: increases in yield due to after-effect sometimes exceeds the effect of the direct action.

In steppe areas the filling fertilizer of rotation with short rotation (5-6-field) is applied 1-2 times. In 9-11-field steam-tilled and grain-tilled crop rotations the basic fertilizer is applied 3-4 times per rotation.

Manure is used primarily as a basic fertilizer, which is better to apply in the black fallow and corn. It is introduced in autumn under autumn plowing or when plowing fallow. Mineral fertilizers in the main reception in the 10-12-field crop rotation make a bare and seeded fallow under winter crops, corn and spring wheat. All other crops of the rotation use the effect of the main fertilizer and receive in the rows at sowing granulated superphosphate or complex fertilizer.

In the conditions of Northern Kazakhstan, with a high content of soil potassium, the fertilizer system is reduced to the development of techniques and methods of optimization of phosphorus and nitrogen nutrition of crops.

The high deficit of phosphorus in the soils of the subzone determines the high efficiency of phosphorus fertilizers for all crops. For example, phosphorus applied to grain crops, depending on the doses and deficit provided a yield increase from 250-500 to 800-900 kg/ha.

On chernozems in the forest-steppe and steppe zones with precipitation of 350-370 mm (l/m2) the pre-sowing application is equal to the basic or even exceeds it. However, in the dry-steppe zone on dark chestnut soils the main application of phosphorus fertilizers in a fallow is 1.5-2 times more effective than the annual pre-sowing. In the dry-steppe zone, a stable increase by seeding is provided only on the first crop after the fallow, where there is enough nitrogen and better moisture conditions.

In fallow fields, in the presence of moisture and under the influence of treatments accumulates a sufficient amount of mineral nitrate nitrogen. The content of mobile forms of phosphorus changes insignificantly. This explains the high efficiency of phosphorus fertilizers on fallow. Fallow is the best place in the crop rotation for the application of phosphorus fertilizers.

They have the greatest effect when applied to the moist soil layer, to a depth of 16-20 cm, but not less than 12 cm, in a zone of stable moisture. In the absence of special machines, fertilizers are made by grain-fertilizer seeders on the cultivated to a depth of 14-16 cm fallow. Surface application of phosphate fertilizer reduces their effectiveness by 2-3 times.

In cereal-grass-row without fallow crop rotations phosphate fertilizers made under the leading crop rotation. In rotations with perennial grasses – under the plowing of perennial grasses. This is the only case when the fertilizer can be applied superficially.

Given the long after-effect of phosphate fertilizers, they are made in a fallow field in a zone of stable moisture – to a depth of 12-20 cm once every 4-5 years, providing a rotation of the rotation.

With the local introduction of optimal doses of phosphate fertilizers recoupment of 1 kg d.a.s. for a rotation of 4-5-field crop rotation is 10-15 kg of grain in favorable years – up to 20 kg.

According to long-term studies of nitrogen regime of soils and nitrogen fertilizer efficiency in the conditions of Northern Kazakhstan (Chernenok V.G., 1993, 1997), the main factors determining the effectiveness of nitrogen fertilizers are: the content in the soil of nitrate nitrogen, mobile phosphorus, their ratio and moisture conditions. Nitrogen fertilizers can increase yields for 2 years.

The predominant mineral form of nitrogen in the soils of Northern Kazakhstan is nitrate. The most favorable conditions for nitrification are in the fallow field, where the nitrate content can increase by 2-3 times, providing a high level of nitrogen nutrition of the first crop after fallow. However, in the case of extremely dry conditions during fallow when there is less than 200 mm of rainfall per year, the nitrification process is suppressed. After such years of unfavorable nitrogen conditions, this affects the first crop after fallow. As the crops [in the rotation] are moved away from the fallow, the nitrate content decreases by 2-4 times.

Phosphate fertilizers are effective with a good level of nitrogen nutrition, that is, on the first crop after fallow, and nitrogen fertilizers – on crops more distant from the fallow.

On the southern carbonate chernozem according to the Kazakh Research Institute of Grain Farming (KazNIIZH) on the second crop after fallow increased yields of cereal crops from nitrogen fertilizers is noted in 22% of cases, on the third – 37%, on the fourth – 60%, on the fifth – 82%.

However, in extremely dry years with precipitation of less than 200 mm per year, nitrogen fertilizers are not advisable, because they will not give effect regardless of the content of nitrogen due to an acute shortage of moisture.

The effectiveness of nitrogen fertilizers depends on the timing of application, which is associated with moisture conditions. In the Black Earth zone with more than 320 mm of precipitation per year, the fall application of ammonium nitrate is inferior to the spring one in terms of efficiency. In the chestnut soil zone with annual precipitation of less than 300 mm, the timing of ammonium nitrate application had no effect on their effectiveness, but in years with rainy autumn the spring application was more effective, and in years with dry spring the autumn application was less effective. The best form of nitrogen fertilizer for spring wheat when applied under pre-sowing cultivation is urea, for barley – ammonium sulfate.

The effectiveness of nitrogen fertilizers increases with increasing phosphorus content to the optimal level, for spring wheat is 35 mg P2O5 /kg soil. With further saturation of soils with phosphorus effect decreases, which is associated with a violation of the relationship between the elements of nutrition.

From nitrogen fertilizers for soils of steppe areas urea, ammonium nitrate, ammonium sulfate are recommended. Physiologically alkaline nitrogen fertilizers increasing soil alkalization are unacceptable.

For non-fallow preceding crops and in cereal-grass-row without fallow crop rotations more effective use of complex nitrogen-phosphorus fertilizers (nitrophos, nitroammophos) at the basic, rowwise application and in top dressing. Ammophos on the efficiency is equal to double superphosphate, but inferior in economic efficiency.

From potassium fertilizers, it is better to apply potassium chloride and potassium sulfate.

Organic fertilizers are applied primarily in the fields with low fertility. Approximate doses of manure for cereals – 20-30 t/ha, row crops – 30-40 t/ha, vegetables – 40-50 t/ha.

Cereal straw can be used as organic fertilizer. In terms of its impact on soil fertility, 1 ton of straw is equivalent to 3-3.5 tons of manure. According to KazNIIZH data, at a yield of 1.5-2.0 t/ha of grain the straw ensures a deficit-free balance of humus in the 4-6-field grain-fallow crop rotations.

Fertilization system of crop rotations under irrigation

The fertilization system of crop rotations under irrigation is built taking into account the specialization, granulometric composition of soils, the availability of nutrients, groundwater table, moisture regime. At the same time methods and timing of applications are used which increase the coefficient of utilization of nutrients and prevent loss to the environment.

When irrigated, plants on all types of soils need nitrogen the most. Application of nitrogen fertilizer on the background of phosphorus or phosphorus and potassium increases the yield of grain of winter and spring wheat and green mass of maize by 1.5-2 times. The effectiveness of phosphate fertilizers is lower than that of nitrogen fertilizers, and occurs mainly with their joint application. Increase in yield of cereals and forage crops from phosphate fertilizers on irrigated lands is usually 20-30%, depending on the provision of phosphorus soils. Potassium fertilizers on irrigated lands are ineffective when applied to wheat, corn and alfalfa. In recent years there has been an increase in the effectiveness of potash fertilizers.

The nitrogen problem is solved comprehensively: through a combination of mineral and organic fertilizers, expansion of alfalfa crops on irrigated land. Phosphorus deficit is covered by mineral phosphorus fertilizers. Mineral fertilizers per hectare of irrigated arable land are applied at full demand. At a high level of agrotechnics the greatest recoupment of fertilizers is observed.

Under irrigation conditions the timing of fertilizer application is important. Phosphate and potash fertilizers under all crops are made in autumn under the main tillage. Nitrogen fertilizer on loamy and clay soils with deep groundwater is made in autumn for plowing or spring for cultivation. On sandy and sandy loam well-drained soils, nitrogen fertilizer is applied in spring before sowing. It is important to choose the right form of nitrogen fertilizer. The best under irrigation conditions are urea, ammonium sulfate, carbophosks. Nitrate forms are undesirable because they significantly migrate through the soil profile.

During vegetation, winter wheat crops are fertilized with nitrogen fertilizers (in late autumn or early spring superficially), corn (in the phase of the 4th-5th leaves by cultivator-fertilizers), alfalfa is fertilized with phosphate fertilizers (superficially in early spring). Feeding with urea or ammonium nitrate during earing to the end of flowering is effective to improve grain quality of spring and winter wheat.

Sources

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