The application of mineral fertilizers has a significant effect on pest populations that motionless  (phytopathogenic propaganda, weed seeds) or sedentary  (nematodes, phytophage larvae) condition  for a long time they survive, persist or dwell in the soil. Pathogens of ordinary root rot are especially widely represented in soils ( B. sorokiniana,  kinds p. Fusarium) The name of the diseases they cause - “ordinary” rot - emphasizes the breadth of habitats on hundreds of host plants. In addition, they belong to different ecological groups of soil phytopathogens: B. sorokiniana  - to temporary inhabitants of the soil, and species of the genus Fusarium  - to the permanent. This makes them convenient objects for elucidating the patterns characteristic of a group of soil, or root, infections in general.
Under the influence of mineral fertilizers, the agrochemical properties of arable soils change significantly compared to their counterparts in virgin and fallow areas. This has a great influence on the survival, vitality, and, consequently, the number of phytopathogens in the soil. We show this by example B. sorokiniana  (table 39).

The data presented indicate that the effect of agrochemical properties of the soil on population density B. sorokiniana is more significant in cereal agroecosystems than in natural ecosystems (virgin soils): the determination index, which indicates the share of influence of the factors under consideration, is 58 and 38%, respectively. It is extremely important that the most significant environmental factors that change the density of the pathogen population in the soil are nitrogen (NO3) and potassium (K2O) in agroecosystems, and humus in natural ecosystems. In agroecosystems, the dependence of the density of the fungal population on soil pH, as well as the content of mobile forms of phosphorus (P2O5), is increasing.
Let us consider in more detail the effect of certain types of mineral fertilizers on the life cycle of soil pests.
Nitrogen fertilizers.
Nitrogen is one of the basic elements necessary for the functioning of both host plants and harmful organisms. It is part of four elements (H, O, N, C), of which 99% of the tissues of all living organisms are composed. Nitrogen as the seventh element of the periodic table, having 5 electrons in the second row, can finish them up to 8 or lose them, being replaced by oxygen. Thanks to this, stable bonds are formed with other macro- and microelements.
Nitrogen is an integral part of proteins from which all their basic structures are created and which determine the activity of genes, including the host plant system — harmful organisms. Nitrogen is a part of nucleic acids (ribonucleic RNA and deoxyribonucleic DNA), which determine the storage and transmission of hereditary information about evolutionary-ecological relationships in general and between plants and pests in ecosystems, in particular. Therefore, the application of nitrogen fertilizers is a powerful factor in both the stabilization of the phytosanitary state of agroecosystems and its destabilization.  This position was confirmed by the mass chemicalization of agriculture.
Plants provided with nitrogen nutrition are distinguished by better development of the aerial mass, bushiness, leaf area, leaf chlorophyll content, grain protein content and gluten content in it.
The main nitrogen sources of both plants and pests are nitric acid salts and ammonium salts.
Under the influence of nitrogen, the main vital function of harmful organisms changes - the intensity of reproduction, and therefore the role of cultivated plants in agroecosystems as sources of reproduction of harmful organisms. Pathogens of root rot temporarily increase their population in the absence of host plants, using mineral nitrogen introduced in the form of fertilizers for direct consumption (Fig. 18).

Unlike mineral nitrogen, the action of organics on pathogens occurs through the microbial decomposition of organic matter. Therefore, an increase in organic nitrogen in the soil correlates with an increase in the soil microflora population, among which antagonists make up a significant proportion. A high dependence of the helminthosporious rot population in agroecosystems on the content of mineral nitrogen was found, and in natural, where organic nitrogen predominates, on the content of humus. Thus, the nitrogen nutrition conditions of host plants and root rot pathogens in agro- and natural ecosystems differ: they are more favorable in agroecosystems with an abundance of nitrogen in the mineral form, and less so in natural ecosystems, where mineral nitrogen is present in less quantity. The relationship of population size B. sorokiniana  with nitrogen in natural ecosystems also manifests itself, but is less quantitatively expressed: the share of influence on the population in the soils of natural ecosystems in Western Siberia is 45% against 90% in agroecosystems. On the contrary, the proportion of the influence of organic nitrogen is more significant in natural ecosystems - respectively 70% against 20%. The introduction of nitrogen fertilizers on chernozems stimulates reproduction more significantly B. sorokiniana  in comparison with phosphorus, phosphorus-potash and full fertilizers (see Fig. 18). However, the stimulation effect differs sharply depending on the forms of nitrogen fertilizers absorbed by plants: it was maximum when magnesium nitrate and sodium nitrate were added and minimal when using ammonium sulfate.
According to the data of I.I. Chernyaeva, G.S. Muromtseva, L.N. Korobova, V.A. Chulkina, and others, ammonium sulfate on neutral and slightly alkaline soils suppresses the germination of phytopathogen propagules quite effectively and reduces the population density of such widespread phytopathogens like species of labor Fusarium, Helminthosporium, Ophiobolus  and loses this quality when combined with lime. Suppression mechanism  due to the absorption of ammonium ion by the roots of plants and the release of rhizosphere of roots hydrogen ion. As a result, the acidity of the soil solution in the rhizosphere of plants increases. Germination of spores of phytopathogens is suppressed. In addition, ammonium - as a less mobile element - has a prolonged effect. It is absorbed by soil colloids and is gradually released into the soil solution.
Ammonification  carried out by aerobic and anaerobic microorganisms (bacteria, actinomycetes, fungi)among which active antagonists of root rot pathogens have been identified. Correlation analysis shows that between the numbers B. sorokiniana  in soils and the number of ammonifiers on chernozem soils of Western Siberia there is an inverse close relationship: r \u003d -0.839 / -0.936.
The nitrogen content in the soil affects the survival of phytopathogens on (c) infected plant residues. So, survival Ophiobolus graminis and Fusarium roseum  was higher on straw in soils rich in nitrogen, while for B. sorokinianaon the contrary, in soils with a low content. With an increase in the mineralization of plant residues under the influence of nitrogen-phosphorus fertilizers, B. sorokiniana is actively displaced: the pathogen population rotted on plant residues when NP was added 12 times less than on plant residues without fertilizer application.
The introduction of nitrogen fertilizers enhances the growth of the vegetative organs of plants, the accumulation of non-protein nitrogen (amino acids) in them, available for pathogens; the water content of tissues increases, the cuticle thickness decreases, the cells increase in volume, their membrane becomes thinner. This facilitates the penetration of pathogens into the tissues of host plants, enhances their susceptibility to disease. Excessively high application rates of nitrogen fertilizers cause an imbalance in the nutrition of plants with nitrogen and an increased development of diseases.
E.P. Durynina and L.L. Velikanov note that a high degree of damage to plants when applying nitrogen fertilizers is associated with a significant accumulation of non-protein nitrogen. Other authors attribute this phenomenon to a change in the quantitative ratio of amino acids during the pathogenesis of diseases. More severe damage to barley B. sorokiniana  noted in case of high content glutamine, threonine, valine and phenylalanine.  On the contrary with a high content of asparagine, proline and alanine, the lesion was negligible.  Content serine and isoleucine  increases in plants grown on the nitrate form of nitrogen, and glycine and cysteine  - on ammonium.
Determined that verticillosis infection amplified when nitrate nitrogen prevails in the root zone and, conversely, weakens when replaced with the ammonium form. The introduction of high doses of nitrogen under cotton (more than 200 kg / ha) in the form of ammonia water, liquefied ammonia, ammonium sulfate, ammophos, urea, calcium cyanamide  leads to a more significant increase in yield and a significant suppression of verticilli infection than when introduced ammonia and Chilean nitrate.  Differences in the effect of nitrate and ammonium forms of nitrogen fertilizers are caused by their different effects on the biological activity of the soil. The C: N ratio and the negative effect of nitrates weaken against the background of the introduction of organic additives.
The introduction of nitrogen fertilizers in the ammonium form reduces the process of reproduction oat cyst nematode  and increases the physiological resistance of plants to it. Thus, the introduction of ammonium sulfate reduces the number of nematodes by 78%, and grain productivity increases by 35.6%. At the same time, the use of nitrate forms of nitrogen fertilizers, on the contrary, contributes to an increase in the population of oat nematodes in the soil.
Nitrogen is the basis of all growth processes in the plant. Concerning the susceptibility of plants to diseases and pests is weaker with optimal plant nutrition.  With an increase in the development of diseases against the nitrogen background of nutrition, a catastrophic decline in productivity does not occur. Ho the safety of products during storage is significantly reduced. Due to the intensity of growth processes, the ratio between the affected and healthy tissue of organs when nitrogen fertilizers are applied changes towards healthy. So, in case of damage to crops by root rot against a nitrogen background of nutrition, the secondary root system simultaneously grows, while in case of nitrogen deficiency, the growth of secondary roots is suppressed.
Thus, the needs of plants and pests in nitrogen as a nutrient coincide. This leads to both an increase in productivity when applying nitrogen fertilizers, and to the multiplication of harmful organisms. Moreover, in agroecosystems mineral forms of nitrogen prevail, especially nitrate, which are directly consumed by pests. Unlike agroecosystems, in natural ecosystems the organic form of nitrogen prevails, consumed by pests only when the organic residues are decomposed by microflora. Among it are many antagonists that suppress all root rot pathogens, but especially specialized ones, such as B. sorokiniana. This limits the propagation of root rot pathogens in natural ecosystems, where their number is constantly maintained at a level below the PV.
Fractional application of nitrogen fertilizers in combination with phosphorus fertilizers, the replacement of the nitrate form with ammonium, stimulate the general biological and antagonistic activity of soils, serve as real prerequisites for stabilizing and reducing the number of harmful organisms in agroecosystems. Added to this is the positive effect of nitrogen fertilizers on increasing endurance (adaptability) to harmful organisms - energetically growing plants have increased compensatory abilities in response to damage and damage caused by pathogens and pests.
Phosphoric fertilizers.
Phosphorus is a part of nucleic acids, macroergic compounds (ATP), participating in the synthesis of proteins, fats, carbohydrates, amino acids. He takes part in photosynthesis, respiration, regulation of the permeability of cell membranes, in the formation and transfer of energy necessary for the life of plants and animals. The main role in the energy processes of cells, tissues and organs of living organisms belongs to ATP (adenosine triphosphoric acid). Without ATP, neither biosynthesis processes nor the breakdown of metabolites in cells can take place. The role of phosphorus in the biological transfer of energy is unique: the stability of ATP in environments where biosynthesis is taking place is greater than the stability of other compounds. This is due to the fact that the energy-rich bond is protected by a negative charge of phosphoryl, which repels water molecules and OH- ions. Otherwise, ATP would easily undergo hydrolysis and decomposition.
When plants are provided with phosphorus nutrition, synthesis processes are intensified in them, root growth is activated, crop maturation is accelerated, drought tolerance is increased, and the development of generative organs is improved.
The main source of phosphorus for plants in agroecosystems is phosphorus fertilizers. Plants absorb phosphorus in the initial phases of growth and are very sensitive to its deficiency during this period.
The application of phosphorus fertilizers has a significant effect on the development of root rot. This effect is achieved even when fertilizing in small doses, in rows when sowing. The positive effect of phosphate fertilizers is due to the fact that phosphorus promotes enhanced growth of the root system, thickening of mechanical tissues, and most importantly, determines the absorbing (metabolic) activity of the root system.
The root system spatially and functionally provides the absorption, transport and metabolism of phosphorus. Moreover, the value of the root system for the absorption of phosphorus is immeasurably higher than nitrogen. Unlike nitrates, phosphorus anions  absorbed by the soil and remain undissolved. A plant can get them only thanks to the roots that directly come into contact with anions in the thickness of the soil. Thanks to proper phosphorus nutrition, the predisposition to pathogens from the root system, especially the secondary one, is reduced. The latter coincides with the increased physiological activity of secondary roots in the supply of plants with phosphorus. Each unit of the volume of secondary roots received (in the experiment with labeled atoms) twice the amount of phosphorus in comparison with the germinal roots.
The application of phosphorus fertilizer slowed down the development of ordinary root rot in all the studied zones of Siberia, even when nitrogen (northern forest-steppe) was in the “first minimum” in the soil. The positive effect of phosphorus was manifested both in the main and in the row application in a small (P15) dose. Row fertilizer is more appropriate with a limited amount of fertilizer.
The effectiveness of phosphorus fertilizers for the vegetative organs of plants varies: the improvement of underground, especially secondary roots was manifested in all zones, and aboveground only in humid and moderately moist (subtaiga, northern forest-steppe). Within one zone, the effect of recovery from phosphorus fertilizer on underground organs was 1.5-2.0 times higher than on aboveground ones. On soil-protective backgrounds, treatments in the steppe zone are especially effective in improving the soil and vegetative organs of spring wheat plants in the calculated norm of nitrogen-phosphorus fertilizers. Strengthening of growth processes under the influence of mineral fertilizers led to increased plant endurance to ordinary root rot. In this case, the leading role was played by that macroelement, the content of which in the soil is minimal: in the mountain-steppe zone - phosphorus, in the northern forest-steppe - nitrogen. In the mountain-steppe zone, for example, a correlation was found between the level of development of root rot (%) by years and the value of grain yield (t / ha):

The correlation is the opposite: the weaker the development of root rot, the higher the grain yield, and vice versa.
Similar results were obtained in the southern forest-steppe of Western Siberia, where the availability of soil with mobile forms of P2O5 was average. The shortage of grain from ordinary root rot was the highest in the aariant without the use of fertilizers. So, on average over 3 years it amounted to 13709 32.9% for barley varieties of Omsk versus 15.6-17.6 in the case of the application of phosphorus, phosphorus-nitrogen and full mineral fertilizers, or almost 2 times higher. The introduction of nitrogen fertilizer, even if the nitrogen was in the soil at the “first minimum”, affected mainly the increase in plant tolerance to the disease. As a result of this, unlike the phosphorus background, the correlation between the development of the disease and the grain yield of nitrogen is not statistically proven.
Long-term studies conducted at the Rotamsted Experimental Station (England) indicate that the biological effectiveness of phosphorus fertilizers against root rot (pathogen Ophiobolus graminis) depends on the fertility of soils and predecessors, varying from 58% to a 6-fold positive effect. Maximum efficiency was achieved with the integrated use of phosphate fertilizers with nitrogen.
According to studies conducted on chestnut soils of the Altai Republic, a significant decrease in the B. sorokiniana population in soil is achieved where phosphorus is contained in the soil at the first minimum (see Fig. 18). The addition under these conditions of nitrogen fertilizers in the norm of N45 and even potassium in the norm of K45, the phytosanitary condition of soils practically does not improve. The biological effectiveness of phosphorus fertilizer in a dose of P45 was 35.5%, and full fertilizer - 41.4% compared to the background, without the use of fertilizers. In this case, the number of conidia with signs of degradation (decomposition) increases significantly.
Increasing plant resistance under the influence of phosphorus fertilizer limits the harmfulness of wireworms, nematodes, reducing the critical period as a result of intensification of growth processes in the initial phases.
The introduction of phosphorus-potassium fertilizers has a direct toxic effect on phytophages. So, when phosphorus-potassium fertilizers are applied, the number of wireworms is reduced by 4-5 times, and when nitrogen fertilizers are added to them, by 6-7 times compared to their initial number, and 3-5 times compared to control data without application fertilizers. Especially sharply reduced the population of sowing nutcracker. The effect of mineral fertilizers on the reduction in the number of wireworms is explained by the fact that pest coverings have selective permeability to salts contained in mineral fertilizers. Penetrate faster and more toxic to wireworms ammonium cations  (NH4 +) then potassium and sodium cations.  Least toxic calcium cations. Anions of fertilizer salts can be arranged in the following descending order of their toxic effect on wireworms: Cl-, N-NO3-, PO4-.
The toxic effect of mineral fertilizers on wireworms varies depending on the humus content of soils, their mechanical composition and pH. The less organic matter is contained in the soil, the lower the pH and the lighter the mechanical composition of the soil, the higher the toxic effect of mineral fertilizers, including phosphorus, on insects.
Potash fertilizers.
Being in the cell sap, potassium retains easy mobility, being held by mitochondria in the plant protoplasm during the day and is partially excreted through the root system at night, and again absorbed in the afternoon. Rains wash away potassium, especially from old leaves.
Potassium contributes to the normal course of photosynthesis, enhances the outflow of carbohydrates from leaf blades to other organs, the synthesis and accumulation of vitamins (thiamine, riboflavin, etc.). Under the influence of potassium, plants acquire the ability to retain water and is easier to tolerate short-term drought. In plants, the cell membrane thickens, and the strength of mechanical tissues increases. These processes contribute to increasing the physiological resistance of plants to pests and adverse abiotic environmental factors.
According to the International Institute of Potash Fertilizers (750 field experiments), potassium reduced the susceptibility of plants to fungal diseases in 526 cases (71.1%), was ineffective in 80 (10.8%) and increased the susceptibility in 134 (18.1%) cases. It is especially effective in healing plants in humid, cool conditions, even with its high content in the soil. Within the West Siberian Lowland, potassium stably produced a positive effect of soil improvement in the subtaiga zones (Table 40).

The introduction of potash fertilizers even with a high potassium content in the soils of all three zones significantly reduced the population of soils B. sorokiniana.  The biological efficiency of potassium was 30-58% versus 29-47% phosphorus and unstable efficiency of nitrogen fertilizer: positive (18-21%) in the sub-taiga and northern forest-steppe, negative (-64%) in the mountain-steppe zone.
The total microbiological activity of the soil and the concentration of K2O in it have a decisive effect on survival Rhizoctonia solani.  Potassium is able to increase the flow of carbohydrates into the root system of plants. Therefore, the most active formation wheat mycorrhiza  goes when making potash fertilizers. Mycorrhiza formation decreases with the introduction of nitrogen due to the consumption of carbohydrates for the synthesis of nitrogen-containing organic compounds. The effect of phosphorus fertilizer was not significant in this case.
In addition to affecting the intensity of reproduction of pathogens and their survival in soil, mineral fertilizers affect the physiological resistance of plants to infection. At the same time, potash fertilizers enhance processes in plants that delay the decomposition of organic substances, increase activity catalase and peroxidase  reduce respiratory rate and loss of dry matter.
Trace elements.
Trace elements make up an extensive group of cations and anions, which have a multifaceted effect on the intensity and nature of the sporulation of pathogens, as well as the resistance of host plants to them. The most important feature of the action of trace elements is their relatively small doses, necessary to reduce the harmfulness of many diseases.
In order to reduce the severity of diseases, it is recommended to use the following trace elements:
- helminthosporiosis of cereals - manganese;
- verticillosis of cotton - boron, copper;
- root rot of cotton - manganese;
- Fusarium wilting of cotton - zinc;
- beet root eater - iron, zinc;
- rhizoctonia of potato - copper, manganese,
- potato cancer - copper, boron, molybdenum, manganese;
- black leg of potatoes - copper, manganese;
- potato verticillosis - cadmium, cobalt;
- black leg and keel of cabbage - manganese, boron;
- phomosis of carrots - boron;
- black apple cancer - boron, manganese, magnesium;
- gray rot of strawberries - manganese.
The mechanism of action of trace elements on different pathogens is different.
During the pathogenesis of root rot on barley, for example, physiological and biochemical processes are disrupted and the elemental composition of plants is unbalanced. In the tillering phase, the content of K, Cl, P, Mn, Cu, Zn decreases and the concentration of Fe, Si, Mg, and Ca increases. Fertilizing plants with trace elements in which the plant is deficient stabilizes metabolic processes in plants. Thus, their physiological resistance to pathogens increases.
Different pathogens need different trace elements. For example, the causative agent of Texas root rot (pathogen Phymatotrichum omnivorum) it was shown that only Zn, Mg, Fe increase the biomass of the mycelium of the pathogen, while Ca, Co, Cu, Al inhibit this process. Absorption of Zn begins with the stage of germination of conidia. At Fusarium graminearum  Zn affects the formation of yellow pigments. Most fungi require the presence of Fe, B, Mn, Zn in the substrate, although in different concentrations.
Boron (B), affecting the permeability of plant cell membranes and the transport of carbohydrates, changes their physiological resistance to phytopathogens.
The choice of optimal doses of micronutrient fertilizers, for example, when applying Mn and Co on cotton, reduces the development of wilt by 10-40%. The use of trace elements is one of the effective ways of healing potatoes from common scab. According to the famous German phytopathologist G. Brazda, manganese reduces the development of common scab by 70-80%. Conditions conducive to the defeat of potato tubers by scab coincide with factors of manganese starvation.  There is a direct correlation between the development of common scab and the manganese content in the peel of potato tubers. With a lack of manganese, the peel becomes rough and crack (see Fig. 4). Favorable conditions arise for the infection of tubers. According to the All-Russian Research Institute of Flax, with a lack of boron in the soil, flax transport of carbohydrates is disrupted, which contributes to the normal development of rhizospheric and soil microorganisms. The introduction of boron into the soil reduces the aggressiveness of the causative agent of flax fusarium in half with an increase in seed yield by 30%.
The influence of micronutrient fertilizers on the development of phytophages and other soil pests is not well understood. They are used to a greater extent for the improvement of crops from ground-air, or leaf-stem, pests.
Trace elements are used in the processing of seed and planting material. They are applied to the soil along with NPK, either by spraying plants or by watering. In all cases the effectiveness of micronutrients in protecting plants from soil pests, especially phytopathogens, increases when they are applied against the background of a complete mineral fertilizer.
Complete mineral fertilizer.  The introduction of a complete mineral fertilizer based on agrochemical cartograms and the normative method has the most favorable effect on the phytosanitary state of soils and crops in relation to soil, or tuber root, infections, improving the soil and root crops used for food and seeds.
Soil improvement using full mineral fertilizer for spring wheat and barley occurs in almost all soil and climatic zones (Table 41).

The biological effectiveness of full mineral fertilizer varied from 14 to 62% in zones: it was higher in relatively humid zones than in the arid (Kulunda steppe), and within permanent zones in permanent crops, where the worst phytosanitary situation was noted.
The role of mineral fertilizers in soil improvement decreases when seeds infected with phytopathogens are sown.  Infected seeds create micro-foci of the pathogen in the soil and, in addition, the pathogen located on (in) the seeds occupies the first ecological niche in the affected organs of plants.
All mineral fertilizers that lower pH on sod-podzolic soil adversely affect propagation of propagules. B. sorokiniana  in the soil (r \u003d -0.737). So, potash fertilizers, acidifying the soil, reduce the phytopathogen population, especially in insufficiently moist soil.
Increasing the physiological resistance of plants to diseases leads to the improvement of underground and aboveground vegetative organs. Even D.N. Pryanishnikov noted that in starving plants, the proportional development of vegetative organs is disturbed. In areas of sufficient (taiga, subtaiga, foothills) and moderate (forest-steppe) humidification in Western Siberia, under the influence of complete mineral fertilizer, recovery significantly increases as underground  (primary, secondary roots, epicotyl), and aboveground  (basal leaves, stem base) autonomic organs. At the same time, in arid conditions (Kulunda steppe), the number of healthy roots, especially secondary ones, is increasing. The improvement of the vegetative organs of plants against a fertilized background is mainly associated with an improvement in the phytosanitary state of the soil (r \u003d 0.732 + 0.886), as well as with an increase in the physiological resistance of the vegetative organs to fusarium-helminthosporious diseases, the predominance of synthesis processes over hydrolysis in them.
For increase physiological resistance to pathogens  diseases nutrient balance is important  especially with respect to N-NO3, P2O5, K2O, which varies by culture. So, to increase the physiological resistance of potato plants to diseases, the ratio N: P: K is recommended 1: 1: 1.5 or 1: 1.5: 1.5 (phosphorus and potassium predominate), and to increase the physiological resistance of cotton to wilt by in the fields populated by the propagation of the pathogen above the PV, they withstand N: P: K as 1: 0.8: 0.5 (nitrogen prevails).
Complete mineral fertilizer affects populations of phytophages living in the soil. As a general pattern, a decrease in the number of phytophages was noted in the absence of a noticeable negative effect on entomophages. So, the mortality of wireworms depends on the concentration of salts in the soil, the composition of cations and anions, the osmotic pressure of liquids in the body of wireworms and the external soil solution. With an increase in metabolic rate in insects, the permeability of their integument to salts increases. Wireworms are especially sensitive to mineral fertilizers in spring and summer.
The effect of mineral fertilizers on wireworms also depends on the humus content in the soil, its mechanical composition and pH values. The less organic matter it contains, the higher the toxic effect of mineral fertilizers on insects. The biological effectiveness of NK and NPK on sod-podzolic soils of Belarus, introduced under barley in the barley-oats-buckwheat crop rotation link, reaches 77 and 85%, respectively, in a decrease in the number of wireworms. At the same time, the number of entomophages (ground beetles, staphylinids) as a percentage of pests does not decrease, and in some cases even increases.
The systematic use of full mineral fertilizer in the fields V.V. Dokuchaev helps reduce the number and severity of wireworms to the level of EPV. As a result, the farm does not require the use of insecticides against these pests.
Mineral fertilizers significantly limit the reproduction rate of soil or root-tuberous harmful organisms, reduce the number and duration of their survival in soil and (c) plant residues due to increased biological and antagonistic activity of the soil, increased resistance and endurance (adaptability)  plants to pests. The application of nitrogen fertilizers increases mainly endurance (compensatory mechanisms)  plants to harmful organisms, and the introduction of phosphorus and potash - physiological resistance to them. Complete mineral fertilizer combines both mechanisms of positive action.
The sustainable phytosanitary effect of mineral fertilizers is achieved by a differentiated approach by zones and crops in determining the doses and balance of nutrients of macro- and micronutrient fertilizers based on agrochemical cartograms and a standard calculation method. However, with the help of mineral fertilizers, a radical improvement of the soil from pathogens of root infections is not achieved. The yield of grain from increasing doses of mineral fertilizers in the conditions of chemicalization of agriculture is reduced if crops are cultivated on soils infected above the threshold of harmfulness.  This circumstance requires the combined use of phytosanitary precursors in crop rotation, mineral, organic fertilizers and biological preparations for enriching the plant rhizosphere with antagonists and reducing the infectious potential of pathogens in soils below PV. For this, soil phytosanitary cartograms (FPK) are compiled and, on their basis, measures for soil improvement are developed.
Soil improvement at the present stage of agricultural development is a fundamental prerequisite for increasing the sustainability and adaptability of agroecosystems in the transition to adaptive-landscape agriculture and adaptive crop production.

Kuban State University

Department of Biology

discipline "Soil ecology"

"Hidden negative effect of fertilizers."

Performed

Afanasyeva L. Yu.

5th year student

(specialty -

"Bioecology")

Checked Bukareva O. V.

Krasnodar, 2010

Introduction ……………………………………………………………………………………… ... 3

1. The effect of mineral fertilizers on the soil ………………………………… ... 4

2. The effect of mineral fertilizers on atmospheric air and water .................. 5

3. The effect of mineral fertilizers on product quality and human health …………………………………………………………… 6

4. Geoecological consequences of the use of fertilizers …………………… ... 8

5. The impact of fertilizers on the environment …………………………… ..10

Conclusion …………………………………………………………………………………… .17

List of used literature ……………………………………………………… ... 18

Introduction

Soil pollution with foreign chemicals causes them great damage. A significant factor in environmental pollution is the chemicalization of agriculture. Even mineral fertilizers, if used improperly, can cause environmental damage with a dubious economic effect.

Numerous studies of agrochemical scientists have shown that different types and forms of mineral fertilizers do not equally affect soil properties. Fertilizers introduced into the soil enter into complex interactions with it. All kinds of transformations take place here, which depend on a number of factors: the properties of fertilizers and soil, weather conditions, agricultural technology. On how the conversion of certain types of mineral fertilizers (phosphorus, potash, nitrogen) occurs, their influence on soil fertility depends.

Mineral fertilizers are an inevitable consequence of intensive farming. It is estimated that in order to achieve the desired effect of the use of mineral fertilizers, their global consumption should be about 90 kg / year per person. The total production of fertilizers in this case reaches 450-500 million tons / year, at present, their global production is 200-220 million tons / year or 35-40 kg / year per person.

The use of fertilizers can be considered as one of the manifestations of the law of increasing energy investment in a unit of agricultural output. This means that in order to get the same yield increase, an increasing amount of mineral fertilizers is required. So, at the initial stages of fertilizer application, an addition of 1 ton of grain per 1 ha ensures the introduction of 180-200 kg of nitrogen fertilizer. The next additional ton of grain is associated with a dose of fertilizers 2-3 times larger.

Ecological consequences of the use of mineral fertilizers  it is advisable to consider from at least three points of view:

Local influence of fertilizers on ecosystems and soils into which they are applied.

Transcendental impact on other ecosystems and their links, primarily on the aquatic environment and atmosphere.

Influence on the quality of products obtained from fertilized soils and human health.

1. The effect of mineral fertilizers on soils

In the soil as a system, such changes that lead to loss of fertility:

Acidity increases;

The species composition of soil organisms is changing;

The circulation of substances is disturbed;

The structure that worsens other properties is destroyed.

There is evidence (Mineev, 1964) that an increased leaching of calcium and magnesium from them is a consequence of an increase in soil acidity when applying fertilizers (primarily acidic nitrogen). To neutralize this phenomenon, it is necessary to introduce these elements into the soil.

Phosphorus fertilizers do not have such a pronounced acidifying effect as nitrogen, but they can cause zinc starvation of plants and the accumulation of strontium in the resulting products.

Many fertilizers contain impurities. In particular, their introduction can increase the radioactive background, lead to the progressive accumulation of heavy metals. Main way reduce these effects  - moderate and scientifically sound use of fertilizers:

Optimal doses;

The minimum amount of harmful impurities;

Alternation with organic fertilizers.

You should also remember the expression that "mineral fertilizers are a means of masking realities." So, there is evidence that more mineral substances are carried out with soil erosion products than they are introduced with fertilizers.

2. The effect of mineral fertilizers on atmospheric air and water

The effect of mineral fertilizers on atmospheric air and water is mainly due to their nitrogen forms. Mineral fertilizer nitrogen enters the air either in free form (as a result of denitrification) or in the form of volatile compounds (for example, in the form of nitrous oxide N2 O).

According to modern concepts, the gaseous loss of nitrogen from nitrogen fertilizers is from 10 to 50% of its application. An effective way to reduce gaseous nitrogen loss is scientifically based their use:

Introduction to the root forming zone for the fastest absorption by plants;

Use of gaseous loss inhibitor substances (nitropyrine).

The most significant impact on water sources, except nitrogen, have phosphorus fertilizers. The removal of fertilizers to water sources is minimized when properly applied. In particular, spreading fertilizers on the snow cover, dispersing them from aircraft near water bodies, and storing in the open air is unacceptable.

3. The effect of mineral fertilizers on product quality and human health

Mineral fertilizers can have a negative effect both on plants and on the quality of plant products, as well as on organisms that consume them. The main of these effects are presented in tables 1, 2.

At high doses of nitrogen fertilizers, the risk of plant diseases increases. There is an excessive accumulation of green mass, and the likelihood of plant lodging sharply increases.

Many fertilizers, especially chlorine-containing (ammonium chloride, potassium chloride), adversely affect animals and humans, mainly through water, which releases the released chlorine.

The negative effect of phosphate fertilizers is associated mainly with the fluorine, heavy metals and radioactive elements contained in them. Fluorine at its concentration in water of more than 2 mg / l can contribute to the destruction of tooth enamel.

Table 1 - The effect of mineral fertilizers on plants and the quality of plant products

Types of fertilizers	The effect of mineral fertilizers
positive	negative
		At high doses or untimely methods of application - accumulation in the form of nitrates, violent growth to the detriment of stability, increased incidence, especially of fungal diseases. Ammonium chloride contributes to the accumulation of Cl. The main accumulators of nitrates are vegetables, corn, oats, and tobacco.
Phosphoric	Reduce the negative effects of nitrogen; improve product quality; contribute to increasing the resistance of plants to diseases.	At high doses, plant toxicosis is possible. They act mainly through the heavy metals they contain (cadmium, arsenic, selenium), radioactive elements and fluorine. The main stores are parsley, onion, sorrel.
Potash	Similar to phosphorus.	Act mainly through the accumulation of chlorine when making potassium chloride. With an excess of potassium - toxicosis. The main sources of potassium are potatoes, grapes, buckwheat, and vegetables.

Table 2 & The impact of mineral fertilizers on animals and humans

Types of fertilizers	Main impacts
Nitrate forms	Nitrates (MPC for water 10 mg / l, for food products - 500 mg / day per person) are restored in the body to nitrites, causing metabolic disorders, poisoning, deterioration of the immunological status, methemoglobinia (oxygen starvation of tissues). When interacting with amines (in the stomach) they form nitrosamines - the most dangerous carcinogens. In children, they can cause tachycardia, cyanosis, eyelash loss, rupture of the alveoli. In animal husbandry: vitamin deficiencies, decreased productivity, urea accumulation in milk, increased morbidity, decreased fertility.
Phosphoric Superphosphate	Act mainly through fluoride. An excess of it in drinking water (more than 2 mg / l) causes damage to tooth enamel in humans, loss of elasticity of blood vessels. With a content of more than 8 mg / l - osteochondrosis.
Potassium chloride Ammonium chloride	Consumption of water with a chlorine content of more than 50 mg / l causes poisoning (toxicosis) in humans and animals.

4. Geoecological consequences of the use of fertilizers

For their development, plants need a certain amount of nutrients (nitrogen, phosphorus, potassium compounds), usually absorbed from the soil. In natural ecosystems, biogens assimilated by vegetation return to the soil as a result of destruction processes in the substance cycle (decomposition of fruits, plant litter, dead shoots, roots). A certain amount of nitrogen compounds is fixed by bacteria from the atmosphere. Some biogens are introduced with sediments. On the negative side of the balance are infiltration and surface runoff of soluble biogen compounds, their removal with soil particles during soil erosion, as well as the conversion of nitrogen compounds into a gaseous phase with its escape into the atmosphere.

In natural ecosystems, the rate of accumulation or expenditure of nutrients is usually slow. For example, for the virgin steppe on the chernozems of the Russian Plain, the ratio between the flow of nitrogen compounds through the boundaries of a selected section of the steppe and its reserves in the upper meter layer is about 0.0001% or 0.01%.

Agriculture upsets the natural, almost closed balance of nutrients. The annual harvest takes away part of the biogens contained in the produced product. In agroecosystems, the rate of removal of nutrients is 1-3 orders of magnitude higher than in natural systems, and the higher the yield, the relatively greater the rate of removal. Therefore, even if the initial supply of nutrients in the soil was significant, in the agroecosystem it can be used up relatively quickly.

In total, for example, around 40 million tons of nitrogen per year, or about 63 kg per 1 ha of grain area, is exported with grain harvest. This implies the need to use fertilizers to maintain soil fertility and increase yields, since with intensive farming without fertilizers, soil fertility decreases already in the second year. Nitrogen, phosphorus and potash fertilizers are usually used in various forms and combinations, depending on local conditions. At the same time, the use of fertilizers masks soil degradation, replacing natural fertility with fertility, based mainly on chemicals.

The production and consumption of fertilizers in the world has grown steadily, increasing during 1950-1990. about 10 times. The average global fertilizer use in 1993 was 83 kg per 1 ha of arable land. Behind this average is a large difference in the consumption of different countries. In the Netherlands, the most fertilizer is used, and there the level of fertilizer application has even declined in recent years: from 820 kg / ha to 560 kg / ha. On the other hand, the average fertilizer consumption in Africa in 1993 was only 21 kg / ha, with 5 kg / ha or less applied in 24 countries.

Along with positive effects, fertilizers also create environmental problems, especially in countries with a high level of their application.

Nitrates are dangerous to human health if their concentration in drinking water or agricultural products is higher than the established MPC. The concentration of nitrates in the water flowing from the fields is usually between 1 and 10 mg / l, and from unplowed lands it is an order of magnitude lower. As the weight increases and the duration of the use of fertilizers increases, more and more nitrates fall into surface and underground waters, making them unsuitable for drinking. If the level of application of nitrogen fertilizers does not exceed 150 kg / ha per year, then approximately 10% of the amount of fertilizers used falls into natural waters. At higher loads, this proportion is even higher.

Particularly serious is the problem of groundwater pollution after nitrates fall into the aquifer. Water erosion, taking away soil particles, also transfers phosphorus and nitrogen compounds contained in them and adsorbed on them. If they fall into water bodies with delayed water exchange, the conditions for the development of the eutrophication process are improved. So, in the US rivers, the main pollutant of water was dissolved and suspended nutrient compounds.

The dependence of agriculture on mineral fertilizers has led to major shifts in the global cycles of nitrogen and phosphorus. Industrial production of nitrogen fertilizers has led to a disruption in the global nitrogen balance due to an increase in the volume of nitrogen compounds available to plants by 70% compared with the pre-industrial period. Excess nitrogen can change the acidity of soils, as well as the content of organic matter in them, which can lead to further leaching of nutrients from the soil and the deterioration of the quality of natural waters.

According to scientists, the flushing of phosphorus from the slopes in the process of soil erosion is at least 50 million tons per year. This figure is comparable to the annual industrial production of phosphate fertilizers. In 1990, as much phosphorus was carried by rivers into the ocean as it was brought into the fields, namely 33 million tons. Since there are no gaseous phosphorus compounds, it moves under the influence of gravity, mainly with water, mainly from continents to oceans . This leads to chronic land-based phosphorus deficiency and another global geo-ecological crisis.

5. Environmental impact of fertilizers

The negative effect of fertilizers on the environment is associated primarily with the imperfection of the properties and chemical composition of fertilizers. Significant the disadvantages of many mineral fertilizers  are:

The presence of residual acid (free acidity) due to the technology of their production.

The physiological acidity and alkalinity resulting from the predominant use by plants of fertilizers of cations or anions. Long-term use of physiologically acidic or alkaline fertilizers changes the reaction of the soil solution, leads to loss of humus, increases the mobility and migration of many elements.

High solubility of fat. In fertilizers, unlike natural phosphate ores, fluorine is in the form of soluble compounds and easily enters the plant. Increased accumulation of fluoride in plants disrupts metabolism, enzymatic activity (inhibits the action of phosphatase), negatively affects the photo- and biosynthesis of protein, the development of fruits. Elevated doses of fluorine inhibit the development of animals and lead to poisoning.

The presence of heavy metals (cadmium, lead, nickel). Phosphorus and complex fertilizers are most contaminated with heavy metals. This is due to the fact that almost all phosphorus ores contain large amounts of strontium, rare earth and radioactive elements. The expansion of production and the use of phosphorus and complex fertilizers leads to environmental pollution by compounds of fluorine and arsenic.

With existing acidic methods of processing natural phosphate raw materials, the utilization of fluorine compounds in the production of superphosphate does not exceed 20-50%, in the production of complex fertilizers it is even less. The fluorine content in superphosphate reaches 1-1.5, in ammophos 3-5%. On average, about 160 kg of fluorine enters the fields with every ton of phosphorus needed by plants.

However, it is important to understand that it is not mineral fertilizers themselves as sources of nutrients that pollute the environment, but their accompanying components.

Soil soluble phosphoric fertilizers  largely absorbed by the soil and become inaccessible to plants and do not move along the soil profile. It was established that the first culture uses only 10-30% of Р2 О5 from phosphate fertilizers, and the rest remains in the soil and undergoes all kinds of transformations. For example, in acidic soils, phosphorus superphosphate is mostly converted to iron and aluminum phosphates, and in chernozemic and in all carbonate soils into insoluble calcium phosphates. The systematic and prolonged use of phosphate fertilizers is accompanied by a gradual cultivation of soils.

It is known that the long-term use of large doses of phosphorus fertilizers can lead to the so-called “phosphate phosphate”, when the soil is enriched with assimilable phosphates and new doses of fertilizers do not have an effect. In this case, an excess of phosphorus in the soil can disrupt the relationship between nutrients and sometimes reduce the availability of zinc and iron to plants. So, in the conditions of the Krasnodar Territory on ordinary carbonate chernozems, with the usual application of P2 O5, corn unexpectedly sharply reduced productivity. I had to find ways to optimize the elemental nutrition of plants. Soil phosphating is a certain stage of cultivation. This is the result of the inevitable process of accumulation of “residual” phosphorus, when fertilizers are applied in an amount exceeding the removal of phosphorus with the crop.

As a rule, this “residual” phosphorus fertilizer is characterized by greater mobility and availability to plants than natural soil phosphates. With the systematic and prolonged application of these fertilizers, it is necessary to change the ratio between nutrients taking into account their residual effect: the dose of phosphorus should be reduced, and the dose of nitrogen fertilizers should be increased.

Potassium fertilizerintroduced into the soil, like phosphorus, does not remain unchanged. Part of it is in the soil solution, part goes into the absorbed-exchange state, and part turns into a non-exchangeable form, inaccessible to plants. The accumulation of available forms of potassium in the soil, as well as turning into an inaccessible state as a result of prolonged use of potash fertilizers, depends mainly on soil properties and weather conditions. So, in chernozem soils, the amount of digestible forms of potassium under the influence of fertilizer, although increasing, is less than in sod-podzolic soils, since in chernozems, potassium fertilizers are more converted into an irreplaceable form. In an area with a large amount of rainfall and irrigation, it is possible to wash out potassium fertilizers beyond the root layer of the soil.

In areas with insufficient moisture, in a hot climate, where soils are periodically moistened and dry out, intense fixation of potassium fertilizer by the soil is observed. Under the influence of fixation, potassium fertilizer goes into an irreplaceable, inaccessible to plants state. Of great importance on the degree of fixation of potassium by soils is the type of soil minerals, the presence of minerals with a high fixing ability. These are clay minerals. Black earth has a greater ability to fix potassium fertilizers than sod-podzolic soils.

Alkalization of the soil caused by the addition of lime or natural carbonates, especially soda, increases fixation. Fixation of potassium depends on the dose of fertilizer: with an increase in the dose of fertilizers applied, the percentage of fixation of potassium decreases. In order to reduce soil fixation of potassium fertilizers, it is recommended to apply potash fertilizers to a sufficient depth to prevent drying out and to make them more often in crop rotation, since soils that are systematically fertilized with potassium, when it is added again, fix it weaker. But fixed potassium fertilizer, which is in an irreplaceable state, also participates in plant nutrition, since over time it can turn into an exchange-absorbed state.

Nitrogen Fertilizers in interaction with soil, they significantly differ from phosphorus and potash. Nitrate forms of nitrogen are not absorbed by the soil, so they can easily be washed out by atmospheric precipitation and irrigation water.

Ammonia forms of nitrogen are absorbed by the soil, but after their nitrification they acquire the properties of nitrate fertilizers. Partially, ammonia can be absorbed by the soil irreplaceably. Non-exchangeable, fixed ammonium, available to plants to a small extent. In addition, nitrogen loss of fertilizers from the soil is possible as a result of volatilization of nitrogen in free form or in the form of nitrogen oxides. When nitrogen fertilizers are applied, the content of nitrates in the soil changes dramatically, since the most easily assimilated compounds are delivered to the fertilizers. The dynamics of nitrates in the soil to a greater extent characterizes its fertility.

A very important property of nitrogen fertilizers, especially ammonia fertilizers, is their ability to mobilize soil reserves, which is of great importance in the zone of chernozem soils. Under the influence of nitrogen fertilizers, organic compounds of the soil undergo mineralization faster and turn into easily accessible forms for plants.

A certain amount of nutrients, especially nitrogen in the form of nitrates, chlorides and sulfates, can penetrate into groundwater and rivers. The consequence of this is the excess of the norms of the content of these substances in the water of wells, springs, which can be harmful to people and animals, and also leads to an undesirable change in hydrobiocenoses and damages fisheries. Migration of nutrients from soil to groundwater in different soil and climatic conditions is not the same. In addition, it depends on the types, forms, doses and timing of the fertilizer used.

In soils of the Krasnodar Territory with a periodically flushing water regime, nitrates are detected to a depth of 10 m or more and merge with groundwater. This indicates periodic periodic migration of nitrates and their inclusion in the biochemical cycle, the initial links of which are soil, mother rock, and groundwater. Such a migration of nitrates can be observed in wet years, when the soils are characterized by leaching water regime. It is during these years that there is a danger of nitrate pollution of the environment when large doses of nitrogen fertilizers are applied in the winter. In years with an uncontaminated water regime, the flow of nitrates into groundwater is completely stopped, although residual traces of nitrogen compounds are observed along the entire profile of the parent rock to groundwater. Their safety is promoted by the low biological activity of this part of the weathering crust.

In soils with uncontaminated water regimes (southern chernozems, chestnut), pollution of the biosphere with nitrates is excluded. They remain closed in the soil profile and are fully included in the biological cycle.

The harmful potential effects of nitrogen from fertilizers can be minimized by maximizing the use of nitrogen by crops. So, you need to take care that, with increasing doses of nitrogen fertilizers, the efficiency of their use of nitrogen by plants increases; there was not a large amount of nitrates unused by plants that are not retained by soils and can be washed out by sediments from the root layer.

Plants tend to accumulate in their bodies nitrates, which are contained in the soil in excess. Productivity of plants is growing, but the products are poisoned. Vegetables, watermelons and melons accumulate nitrates especially intensively.

In Russia, the MPC of plant-derived nitrates has been adopted (table 3). The permissible daily dose (DSD) for a person is 5 mg per 1 kg of weight.

Table 3 - Permissible levels of nitrates in products

plant origin, mg / kg

Product	Priming
open	protected
Potatoes
White cabbage
Beetroot
Leafy vegetables (lettuce, spinach, sorrel, cilantro, lettuce, parsley, celery, dill)
Sweet pepper
Table grapes
Baby food (canned vegetables)

Nitrates themselves do not have a toxic effect, but under the influence of some intestinal bacteria, they can turn into nitrites, which have significant toxicity. Nitrites, combined with blood hemoglobin, translate it into methemoglobin, which prevents the transfer of oxygen through the circulatory system; a disease develops - methemoglobinemia, which is especially dangerous for children. Symptoms of the disease: fainting, vomiting, diarrhea.

Looking for new ways to reduce nutrient loss and limit environmental pollution :

To reduce nitrogen losses from fertilizers, slow-acting nitrogen fertilizers and nitrification inhibitors, films, additives are recommended; encapsulation of fine-grained fertilizers is introduced by shells of sulfur and plastics. A uniform release of nitrogen from these fertilizers eliminates the accumulation of nitrates in the soil.

The use of new, highly concentrated, complex mineral fertilizers is of great importance to the environment. They are characterized by the fact that they are devoid of ballast substances (chlorides, sulfates) or contain a small amount of them.

Some facts of the negative impact of fertilizers on the environment are associated with errors in the practice of their use, with insufficiently justified methods, terms, and norms for their application without regard to soil properties.

Hidden negative effect of fertilizers  It can be manifested by its effect on the soil, plants, and the environment. When drawing up the calculation algorithm, the following processes should be considered:

1. Effect on plants - a decrease in the mobility of other elements in the soil. As ways to eliminate the negative consequences, regulation of effective solubility and effective ion exchange constant is applied due to changes in pH, ionic strength, and complexation; foliar top dressing and the introduction of nutrients in the root zone; regulation of plant selectivity.

2. Deterioration of the physical properties of soils. As ways to eliminate the negative consequences, the forecast and balance of the fertilizer system are used; builders are used to improve soil structure.

3. Deterioration of water properties of soils. As ways to eliminate the negative consequences, the forecast and balance of the fertilizer system are used; components that improve the water regime are used.

4. Reducing the flow of substances into plants, competition for absorption by the root, toxicity, changes in the charge of the root and root zone. As ways to eliminate the negative consequences, a balanced fertilizer system is used; foliar top dressing of plants.

5. The manifestation of imbalance in the root systems, the violation of metabolic cycles.

6. The appearance of imbalance in the leaves, a violation of the metabolism cycle, the deterioration of technological and taste.

7. Toxicity of microbiological activity. As ways to eliminate the negative consequences, a balanced fertilizer system is used; increased soil buffering; introduction of food sources for microorganisms.

8. Toxicity of enzymatic activity.

9. Toxicity of the animal kingdom of the soil. As ways to eliminate the negative consequences, a balanced fertilizer system is used; increased soil buffering.

10. Decrease in adaptation to pests and diseases, extreme conditions, in connection with overfeeding. As measures to eliminate negative consequences, optimization of the ratio of batteries is recommended; fertilizer dose regulation; integrated plant protection system; application of foliar top dressing.

11. Loss of humus, a change in its fractional composition. To eliminate the negative consequences, applying organic fertilizers, creating a structure, optimizing the pH, regulating the water regime, and balancing the fertilizer system are used.

12. The deterioration of the physico-chemical properties of soils. Ways of elimination - optimization of the fertilizer system, introduction of ameliorants, organic fertilizers.

13. The deterioration of the physical and mechanical properties of soils.

14. The deterioration of the air regime of the soil. To eliminate the negative effect, it is necessary to optimize the fertilizer system, introduce ameliorants, and create a soil structure.

15. Soil fatigue. It is necessary to balance the fertilizer system, strictly implement the crop rotation plan.

16. The appearance of toxic concentrations of individual elements. To reduce the negative impact, a balanced fertilizer system, an increase in soil buffering, precipitation and removal of individual elements, and complexation are necessary.

17. An increase in the concentration of individual elements in plants is above the permissible level. It is necessary to lower fertilizer standards, balance the fertilizer system, foliar top dressing in order to compete with the entry of toxicants into plants, and the introduction of toxicant antagonists into the soil.

The main the reasons for the appearance of a hidden negative effect of fertilizers in soils  are:

Unbalanced application of various fertilizers;

Excess of applied doses in comparison with the buffer capacity of individual ecosystem components;

Directional selection of forms of fertilizers for certain types of soils, plants and environmental conditions;

Wrong application dates for specific soils and environmental conditions;

The introduction together with fertilizers and ameliorants of various toxicants and their gradual accumulation in the soil is above the permissible level.

Thus, the use of mineral fertilizers is a fundamental transformation in the field of production in general and most importantly in agriculture, which allows us to fundamentally solve the problem of food and agricultural raw materials. Without fertilizer, agriculture is now unthinkable.

With proper organization and control of the application, mineral fertilizers are not dangerous for the environment, human and animal health. Optimal scientifically-based doses increase plant productivity and increase production.

Conclusion

Every year, the agro-industrial complex is resorting more and more to the help of modern technologies in order to increase soil productivity and crop yields, without thinking about what impact they have on the quality of a particular product, human health and the environment as a whole. Unlike agrarians, environmentalists and doctors around the world question the excessive enthusiasm for biochemical innovations that literally occupied the market today. Fertilizer producers, across each other, describe the benefits of their own invention, without mentioning a word that improper or excessive fertilizer application can have a detrimental effect on the soil.

Experts have long established that an excess of fertilizers leads to disruption of the ecological balance in soil biocenoses. Chemical and mineral fertilizers, especially nitrates and phosphates, worsen the quality of food products, and also significantly affect human health and the stability of agrocenoses. Ecologists are especially worried that biogeochemical cycles are violated in the process of soil pollution, which subsequently leads to an aggravation of the general environmental situation.

List of references

1. Akimova T. A., Haskin V. V. Ecology. Man - Economy - Biota - Environment. - M., 2001

2. Valkov V. F., Stompel Yu. A., Tulipov V. I. Soil science (soils of the North Caucasus). - Krasnodar, 2002.

3. Golubev G. N. Geoecology. - M, 1999.

Of the individual nutrients, the formation of the generative organs of wintering eyes of grapes and the increase in frost resistance of plants are positively influenced by potash and phosphorus fertilizers, which contribute to earlier ripening of grapes and the rapid completion of the growing season. With a lack of potassium in the plant, the accumulation of soluble forms of nitrogen is observed, and the synthesis of protein substances and the accumulation of carbohydrates slow down. Such a change in the metabolic process in plants leads to a decrease in their frost resistance.
Therefore, the soil nutrition regime is of great importance for increasing the frost resistance of a grape plant. Frost tolerance of plants increases when all the necessary nutrients are provided, otherwise it decreases. Due to the lack or excess of individual nutrients, the normal course of plant development is disrupted. With a lack of any of the nutrients, the plants are poorly assimilated and, as a result, do not postpone the necessary supplies of plastic substances for the winter. The hardening of such plants in the fall is unsatisfactory. Therefore, the fertilizer of vineyards should be considered as a necessary agricultural technique that improves their frost resistance.
Other agricultural measures are of great importance in increasing the frost resistance of grape bushes: bushes loading, green operations, garter shoots, etc. Overloading bushes with crops on a low agrotechnical background weakens the growth of shoots, worsens their ripening, which also reduces their frost resistance. In underloaded bushes, the growth may turn out to be excessively strong and long, as a result of which a general delay in the growing season can also lead to unripening of the vine and, consequently, to a decrease in plant resistance to low temperatures. Thus, those plants that for one reason or another were not sufficiently prepared for winter are especially damaged by low temperatures.
Studies on the influence of the mineral nutrition regime on the frost resistance of a grape plant conducted in Armenia on the Voskeat cultivar showed that bushes that were fertilized with NPK were better preserved during winter frosts than bushes that received only nitrogen or partial fertilizer (Table 10 )

INFLUENCE OF SOIL TREATMENT AND MINERAL FERTILIZER ON THE AGROPHYSICAL PROPERTIES OF TYPICAL CHERNOZEM

G.N. Cherkasov, E.V. Dubovik, D.V. Dubovik, S.I. Kazantsev

Annotation. As a result of the studies, the ambiguous influence of the main tillage method for winter wheat and corn and mineral fertilizers on the indicators of the agrophysical state of typical black soil was established. Optimum indicators of density, structural state were obtained during dump plowing. It was revealed that the use of mineral fertilizers worsens the structurally-aggregate state, but contributes to an increase in the water resistance of soil units during dump plowing with respect to zero and surface treatments.

Key words: structural-aggregate state, soil density, water resistance, tillage, mineral fertilizers.

Fertile soil, along with a sufficient nutrient content, must have favorable physical conditions for the growth and development of crops. It has been established that the soil structure is the basis of favorable agrophysical properties.

Chernozem soils have a low degree of anthropotolerance, which suggests a high degree of influence of anthropogenic factors, the main of which is soil cultivation, as well as a number of other measures that are used to care for crops and contribute to the violation of a very valuable granular structure, as a result of which it can be sprayed or, conversely, lump, which is permissible to certain limits in the soil.

Thus, the aim of this work was to study the effect of soil cultivation, mineral fertilizers and the previous culture on the agrophysical properties of typical black soil.

The studies were conducted in 2009-2010. in LLC AgroSil (Kursk region, Sudzhansky district), on typical heavy loamy chernozem. Agrochemical characteristics of the plot: pHx1 - 5.3; humus content (according to Tyurin) - 4.4%; mobile phosphorus (according to Chirikov) - 10.9 mg / 100 g; exchange potassium (according to Chirikov) - 9.5 mg / 100 g; alkaline hydrolyzed nitrogen (according to Kornfield) - 13.6 mg / 100 g. Cultivated crops: winter wheat cultivar "Augusta" and corn hybrid PR-2986.

The following methods of primary tillage were studied in an experiment: 1) dump plowing by 20-22 cm; 2) surface treatment - 10-12 cm; 3) zero tillage - direct sowing by John Deere seeder. Mineral fertilizers: 1) without fertilizers; 2) for winter wheat N2 ^ 52 ^ 2; for corn K14eR104K104.

Samples were taken in the third decade of May, in a layer of 0-20 cm. Soil density was determined by the drilling method according to N. A. Kachinsky. To study the structurally-aggregate state, undisturbed soil samples weighing more than 1 kg were selected. To distinguish structural units and aggregates, the method of N. I. Savvinov was used to determine the structural-aggregate composition of the soil — dry and wet sieving.

Soil density is one of the main physical characteristics of the soil. An increase in soil density leads, as a rule, to a denser packing of soil particles, which in turn leads to a change in water, air and thermal conditions, which

subsequently negatively affects the development of the root system of agricultural plants. At the same time, the requirements of different plants for soil density are not the same and depend on the type of soil, the mechanical composition, and the cultivated crop. So, the optimum soil density for crops is 1,051.30 g / cm3, for corn - 1.00-1.25 g / cm3.

Studies have shown that under the influence of various tillages, a change in density occurs (Figure 1). Regardless of the cultivated crop, the highest soil density was in the variants with zero cultivation, somewhat lower during surface cultivation. Optimum soil density is noted on options with dump plowing. Mineral fertilizers with all methods of primary processing contribute to an increase in soil density.

The obtained experimental data confirm the ambiguity of the influence of the methods of primary tillage on the indicators of its structural state (table 1). So, in variants with zero cultivation, the lowest content of agronomically valuable aggregates (10.0-0.25 mm) in the arable soil layer was noted, in relation to the surface cultivation and dump plowing.

Dump Surface Kulevaya

processing processing

The method of primary tillage

Figure 1 - Change in the density of typical chernozem depending on the processing methods and fertilizers under winter wheat (2009) and corn (2010)

Nevertheless, the structural coefficient characterizing the state of aggregation decreased in the series: surface treatment ^ dump plowing ^ zero treatment. The structural and aggregate state of chernozem is influenced not only by the method of tillage, but also by the cultivated crop. When cultivating winter wheat, the number of agronomically valuable aggregates and the structural coefficient were higher by 20% on average than in the soil under maize. This is due to the biological features of the structure of the root system of these crops.

Considering the fertilizer factor, I would like to note that the use of fertilizers led to a noticeable decrease in both the agronomically valuable structure and the structural coefficient, which is quite natural, since in the first and second years after application, the structure of the aggregates and the agrophysical properties of the soil deteriorate - the density of the aggregates increases , the pore space is filled with a finely divided part, the porosity decreases and the granularity is almost halved.

Table 1 - the Impact of the method of tillage and mineral fertilizers on the indicators of structural

Another indicator of the structure is its resistance to external influences, among which the most significant is the effect of water, since the soil must retain its unique lumpy-granular structure after heavy rainfall and subsequent drying. This quality of the structure is called water resistance or water resistance.

The content of water-resistant aggregates (\u003e 0.25 mm) is a criterion for assessing and predicting the stability of the folding of the arable layer over time, its resistance to the degradation of physical properties under the influence of natural and anthropogenic factors. The optimum content of water-resistant aggregates\u003e 0.25 mm in the arable layer of different soil types is 40-70 (80)%. When studying the influence of primary processing methods (table 2), it was found that with zero treatment, the sum of water-resistant aggregates was higher than with surface treatment and dump plowing.

Table 2 - Change in water resistance macro

This is directly related to the weighted average diameter of water-resistant aggregates, since zero treatment increases the size of soil units that are water-resistant. The structural coefficient of water-resistant aggregates decreases in a row: surface treatment ^ zero treatment ^ dump plowing. According to

on an indicative scale, the criterion of water-strength of aggregates at zero treatment is rated as very good, and with surface treatment and dump plowing - as good.

Studying the influence of the cultivated culture, it was found that in the soil under corn the weighted average diameter, structural coefficient, and the sum of water-resistant aggregates were higher than under winter wheat, which is associated with the formation of a powerful root system in volume and mass under grain crops, which contributed to the formation more water resistance under corn. The water resistance criterion behaved differently and was higher in the soil under wheat than under corn.

When applying fertilizers on the option with dump plowing, the structural coefficient, the weighted average diameter, and the sum of the waterproof units increased. Since the dump plowing takes place with a turnover of the formation and much deeper than the surface and especially the zero treatment, the incorporation of mineral fertilizers occurs deeper, therefore, the humidity is deeper at the depth, which contributes to a more intensive decomposition of plant residues, due to which there is an increase water resistance of the soil. On the options with the use of surface and zero tillage, all studied indicators of soil water resistance with the use of mineral fertilizers decreased. The water resistance criterion for soil aggregates has increased in all test cases due to the fact that this indicator is calculated not only from wet sieving, but also from dry sieving.

The ambiguous influence of the studied factors on the indicators of the agrophysical state of typical chernozem has been established. So, the most optimal indicators of density, structural state were revealed during dump plowing, somewhat worse during surface and zero treatments. Water resistance indicators decreased in a row: zero treatment ^ surface treatment ^ dump plowing. The use of mineral fertilizers worsens the structurally-aggregate state, but contributes to an increase in the water resistance of soil units during dump plowing in relation to zero and surface treatments. When cultivating winter wheat, indicators characterizing structural

Mineral fertilizers: benefits and harms

Yes, the crop from them is growing,

But nature is ruining.

Nitrates eat people

More and more from year to year.

World production of mineral fertilizers is growing rapidly. Every decade, it increases by about 2 times. The yield of crops from their application, of course, is growing, but this problem has many negative aspects, and this worries a lot of people. It is not for nothing that in some Western countries the government supports vegetable growers who grow products without the use of mineral fertilizers - environmentally friendly.

MIGRATION OF NITROGEN AND PHOSPHORUS FROM SOIL

It is proved that from the nitrogen introduced into the soil, plants absorb about 40%, the rest of the nitrogen is washed out of the soil by rain and evaporates in the form of gas. To a lesser extent, but phosphorus is washed out of the soil. The accumulation of nitrogen and phosphorus in groundwater leads to pollution of water bodies, they quickly age and turn into swamps, because the increased content of fertilizers in the water entails the rapid growth of vegetation. Dying plankton and algae are deposited on the bottom of water bodies, this leads to the release of methane, hydrogen sulfide and to a decrease in the supply of water-soluble oxygen, which causes fish to freeze. The species composition of valuable fish is also declining. The fish did not begin to grow to normal size, it began to age earlier, to die earlier. Plankton in reservoirs accumulates nitrates, fish feed on them, and eating such fish can lead to stomach diseases. And the accumulation of nitrogen in the atmosphere leads to acid rain, acidifying the soil and water, destroying building materials, oxidizing metals. Forests and the animals and birds living in them suffer from all this, and fish and mollusks die in reservoirs. There is a report that on some plantations where mussels are harvested (these are edible mollusks, they used to be very appreciated), they became inedible, moreover, there were cases of poisoning by them.

INFLUENCE OF MINERAL FERTILIZERS ON SOIL PROPERTIES

Observations show that the humus content in soils is constantly decreasing. Fertile soils, chernozems at the beginning of the century contained up to 8% humus. Now there are almost no such soils. Podzolic and sod-podzolic soils contain 0.5-3% humus, gray forest soils - 2-6%, meadow chernozems - more than 6%. Humus serves as a repository of the basic elements of plant nutrition; this is a colloidal substance, particles of which hold nutrients on their surface in a form accessible to plants. Humus is formed when microorganisms decompose residues of plant origin. Humus cannot be replaced with any mineral fertilizers, on the contrary, they lead to the active mineralization of humus, the soil structure deteriorates, from colloidal lumps holding water, air, nutrients, the soil turns into a dusty substance. From natural soil to artificial. Mineral fertilizers provoke leaching of calcium, magnesium, zinc, copper, manganese, etc. from the soil, this affects the processes of photosynthesis, reduces the resistance of plants to diseases. The use of mineral fertilizers leads to soil compaction, a decrease in its porosity, and a decrease in the proportion of granular aggregates. In addition, the acidification of the soil, which inevitably occurs when applying mineral fertilizers, requires an increasing amount of lime. In 1986, 45.5 million tons of lime was added to the soil in our country, but this did not compensate for the loss of calcium and magnesium.

SOIL POLLUTION BY HEAVY METALS AND TOXIC ELEMENTS

The raw materials used for the production of mineral fertilizers contain strontium, uranium, zinc, lead, cadmium, etc., which are technologically difficult to extract. As impurities, these elements enter superphosphates and potash fertilizers. Heavy metals are the most dangerous: mercury, lead, cadmium. The latter destroys red blood cells in the blood, disrupts the kidneys, intestines, softens the tissues. A healthy person weighing 70 kg without harm to health can receive up to 3.5 mg of lead, 0.6 mg of cadmium, 0.35 mg of mercury per week with food. However, on highly fertilized soils, plants can also accumulate large concentrations of these metals. For example, in cow's milk there can be up to 17-30 mg of cadmium in 1 liter. The presence of uranium, radium, and thorium in phosphate fertilizers increases the level of internal exposure of humans and animals when plant food enters their body. The composition of superphosphate also includes fluorine in an amount of 1-5%, and its concentration can reach 77.5 mg / kg, causing various diseases.

MINERAL FERTILIZERS AND SOIL LIVING WORLD

The use of mineral fertilizers causes a change in the species composition of soil microorganisms. The number of bacteria capable of assimilating the mineral forms of nitrogen increases significantly, but the number of symbiont micro fungi in the plant rhizosphere decreases (rhizosphere-   this is a 2-3 mm soil area adjacent to the root system). The number of nitrogen-fixing bacteria in the soil is also decreasing.-   in them, as it were, there is no need. As a result, the root system of plants reduces the release of organic compounds, and their volume was about half the mass of the aboveground part, and plant photosynthesis is reduced. Toxin-forming micro fungi are activated, the number of which under natural conditions is controlled by beneficial microorganisms. The application of lime does not save the situation, but sometimes leads to an increase in soil contamination by root rot pathogens.

Mineral fertilizers cause severe depression of soil animals: foottails, roundworms and phytophages (they feed on plants), as well as a decrease in the enzymatic activity of the soil. And it is formed by the activity of all soil plants and living creatures of the soil, while the enzymes get into the soil as a result of their release by living organisms that die off microorganisms. It has been established that the use of mineral fertilizers reduces the activity of soil enzymes by more than two times.

HUMAN HEALTH PROBLEMS

In the human body, nitrates that are ingested are absorbed into the digestive tract, enter the bloodstream, and with it-   in the fabric. About 65% of nitrates are converted to nitrites already in the oral cavity. Nitrites oxidize hemoglobin to metahemoglobin, which has a dark brown color; he is not able to carry oxygen. The norm of metahemoglobin in the body-   2%, and a larger amount causes various diseases. With 40% methemoglobin in the blood, a person can die. In children, the enzymatic system is poorly developed, and therefore nitrates are more dangerous for them. Nitrates and nitrites in the body turn into nitroso compounds, which are carcinogens. In experiments on 22 animal species, it was proved that these nitroso compounds cause the formation of tumors on all organs except bones. Nitrosoamines, having hepatotoxic properties, also cause liver disease, in particular hepatitis. Nitrites lead to chronic intoxication of the body, weaken the immune system, reduce mental and physical performance, exhibit mutagenic and embrinotoxic properties.

In drinking water, the nitrate content is constantly increasing. Now they should be no more than 10 mg / l (GOST requirements).

For vegetables, the maximum standards for nitrates in mg / kg are established. These standards are constantly being adjusted upward. The level of the maximum permissible concentration of nitrates, now accepted in Russia, and the optimum acidity of the soil for some vegetables are given in the table (see below).

The actual nitrate content in vegetables, as a rule, exceeds the norm. The maximum daily dose of nitrates, which does not adversely affect the human body,- 200-220 mg per 1 kg of body weight. As a rule, 150-300 mg, and sometimes up to 500 mg per 1 kg of body weight, actually enter the body.

QUALITY OF PRODUCTS

Increasing crop yields, mineral fertilizers affect their quality. In plants, the carbohydrate content decreases and the amount of crude protein increases. In potatoes, the starch content decreases, and in grain crops the amino acid composition changes, i.e. protein nutrition is reduced.

The use of mineral fertilizers in growing crops also affects the storage of products. A decrease in sugar and dry matter in beets and other vegetables leads to a deterioration in their shelf life. The flesh darkens more strongly in potatoes, while preserving vegetables, nitrates cause corrosion of the metal of the cans. It is known that more nitrates are found in leaf veins in salads, spinach, up to 90% of nitrates are concentrated in the core of carrots, in the upper part of beets-   up to 65%, their number increases during storage of juice and vegetables at high temperature. Vegetables from the beds are better to harvest mature and in the afternoon-   then they have less nitrates. Where do nitrates come from, and when did this problem arise? There have always been nitrates in products, just their quantity has been growing recently. The plant feeds, takes nitrogen from the soil, nitrogen accumulates in the tissues of the plant, this is a normal phenomenon. Another thing is when there is an excess of this nitrogen in the tissues. Nitrates alone are not dangerous. Some of them are excreted from the body, another part is converted into harmless and even useful compounds. And the excess part of nitrates turns into salts of nitrous acid-   these are nitrites. They deprive red blood cells of the opportunity to supply oxygen to the cells of our body. As a result, metabolism is disturbed, the central nervous system suffers-   central nervous system, the body's resistance to disease is reduced. Among vegetables champion nitrate accumulation - beet. Less of them in cabbage, parsley, onions. No nitrates in ripe tomatoes. There are none in red and black currants.

For less consumption of nitrates, it is necessary to remove parts from vegetables in which there are more nitrates. In cabbage, these are stumps, in cucumber, radish, nitrates accumulate in the spine. In squash, this is the upper part adjacent to the peduncle, in the zucchini-   peel, ponytail. The immature pulp of watermelon and melon, adjacent to the crusts, is rich in nitrates. Salads must be handled very carefully. You need to use them immediately after manufacture, and refuel-   sunflower oil. Microflora quickly grows in sour cream and mayonnaise, which turns nitrates into nitrites. Particularly contributing to this is a change in temperature when we put inedible salads or un-drunk juices in the refrigerator and get them out of there several times. When preparing soup, vegetables should be well washed, peeled, and removed the most dangerous places, one hour should be kept in water by adding salt, a 1% solution to it. It well reduces the nitrate content in food, stewing vegetables, frying potatoes in deep fat. And after eating, to compensate for nitrates, you need to drink green tea, and children need to be given ascorbic acid. And ending the conversation about nitrates, we wish you all good health!

Culture	Level utterly permissible Concentration Nitrate, mg / kg	Optimal acidity soil pH
Tomato	300	5,0-7,0
Potatoes	250	5,0-7,0
Cabbage	900	6,0-7,5
Squash	400	5,5-7,5
Beet	1400	6,5-7,5
Cucumber	400	6,5-7,5
Carrot	250	6,0-8,0
Banana	200
Melon		5,5-7,5
Watermelon		5,5-7,5

N. Nilov