The influence of mineral fertilizers on the development of harmful organisms. Influence of mineral fertilizers on product quality and human health Fertilizer application rates

Each owner of a summer cottage is engaged in fertilization of the soil, who has a desire to get a harvest from the crops grown. What fertilizers are, the norms of their soil, we have already considered in our previous articles. Today we want to pay attention to the effect of fertilizers on plants and humans.

Indeed, why are fertilizers necessary and how do they affect certain indicators of crop growth, and on the person himself? We will answer these questions right now.

Such topics are often raised at the global level, because the conversation is not about a small piece of land, but about industrial-scale fields to meet the needs of an entire region or even a country. It is clear that the number of fields for agricultural crops is constantly growing, and each field cultivated once becomes forever a platform for growing certain plants. Accordingly, the land is depleted, and every year the harvest is significantly reduced. This leads to expenses, and sometimes to bankruptcy of enterprises, hunger, deficits. The primary reason for this is the lack of nutrients in the soil, which we have long been compensating for with special fertilizers. Of course, it is not entirely correct to give an example of multi-hectare fields, but the results can be recalculated for the area of ​​our summer cottages, because everything is proportional.

So, fertilizing the soil. Of course, it is extremely necessary, be it a garden with fruit trees, a vegetable garden with vegetables, or a flower bed with ornamental plants and flowers. You don't need to fertilize the soil, but you yourself will soon notice the quality of the plants and fruits on the permanent, depleted soil. Therefore, we recommend that you do not save on high-quality fertilizers and systematically fertilize the soil with them.

Why do you need fertilizers (video)

Fertilizer application rates

We are used to using mainly, but their number is limited. What to do in this case? Of course, turn to chemistry for help, and fertilize the site, which, fortunately, we are not running out of. But, with this type of fertilizer, you should be more careful, as they have an increased effect on the quality of soil for plants, on humans and the environment... The correct amount is sure to provide the soil with nutrients that will soon be “delivered” to the plants and will help to increase the yield. At the same time, mineral fertilizers will normalize the required amount of substances in the soil and maximize its fertility. But, this is only if the fertilizer dose, application time and other parameters are performed correctly. If not, then the effect of nitrogen fertilizers, phosphate and potash fertilizers on the soil may not be very positive. Therefore, before using such fertilizers, try not only to study the norms and parameters of their application to the soil, but also to choose high-quality mineral fertilizers, the safety of which has passed the control of the manufacturer and special authorities.

The influence of organic fertilizers on the content of trace elements in the soil (video)

The effect of fertilizers on plants

Excess

Through practical research, scientists have established how certain fertilizers affect plants. Now, by external indicators, you can understand how correct the dosage of fertilizers was, whether there was an overabundance or lack of them:

• Nitrogen... If there is too little fertilizer in the soil, then the plants look pale and painful, have a light green color, grow very slowly and die prematurely from yellowing, dryness and leaf fall. An excess of nitrogen leads to a delay in flowering and maturation, overdevelopment of the stems and a change in the color of the plant to dark green;
• Phosphorus... Lack of phosphorus in the soil leads to stunted growth and slow ripening of fruits, a change in the color of the leaves of the plant towards dark green with a kind of bluish tint, and lightening or gray at the edges. If there is a lot of phosphorus in the soil, then the plant will develop too quickly, because of which it can go into the growth of the stem and leaves, while the fruits at this time will be small and in small quantities;
• Potassium. Lack of potassium will provide the plant with delayed development, yellowing of leaves, their wrinkling, curling and partial death. An excess of potassium closes the pathways for nitrogen entry into the plant, which can significantly affect the development of a plant of any crop;
• Calcium... A low intake of potassium will damage the apical buds as well as the root system. If there is enough potassium, then no change should follow.

Flaw

With the rest of the elements, everything is a little different, that is, the plants will react only to their lack in the soil. So:

• Magnesium... Slow growth, and possibly its stop, lightening of the plant, yellowing, and possibly redness and the acquisition of a purple hue in the area of ​​leaf veins;
• Iron... Retardation of growth and development, as well as chlorosis of the leaves - light green, sometimes almost white;
• Copper. Chlorosis of the leaves, increased bushiness of the plant, discoloration are possible;
• Boron... Boron deficiency causes the apical buds to die off during decay.

It is worth noting the fact that often it is not the lack of fertilizer itself that makes the plants externally altered, namely, the weakening of the plant and the diseases that may occur with the lack of fertilizers. But, as you can see, negative consequences are also possible from an overabundance of fertilizers.

The effect of fertilization on the quality and condition of fruits (video)

The effect of fertilizers on humans

An excess of nutrients in the soil, due to improper fertilization, can become dangerous for humans. Many chemical elements, entering the plant through biological processes, are transformed into toxic elements, or contribute to their production. Many plants initially contain similar substances, but their doses are negligible and do not in any way affect the healthy life of a person. This is typical of many popular plants that we eat: dill, beets, parsley, cabbage, and so on.

Organic fertilizers are substances of plant and animal origin introduced into the soil in order to improve the agrochemical properties of the soil and increase the yield. Various types of manure, bird droppings, composts, and green fertilizers are used as organic fertilizers. Organic fertilizers have a multifaceted effect on agronomic properties:

• in their composition, all the nutrients necessary for plants enter the soil. Each ton of dry matter of cattle manure contains about 20 kg of nitrogen, 10 - phosphorus, 24 - potassium, 28 - calcium, 6 - magnesium, 4 kg of sulfur, 25 g of boron, 230 - manganese, 20 - copper, 100 - zinc, etc. etc. - this fertilizer is called complete.
• unlike mineral fertilizers, organic fertilizers are less concentrated in terms of nutrient content,
• manure and other organic fertilizers serve as a source of CO2 for plants. When 30 - 40 tons of manure is introduced into the soil per day during the period of intensive decomposition, 100 - 200 kg / ha of CO2 are released per day.
• organic fertilizers are an energy material and a food source for soil microorganisms.
• a significant part of the nutrients in organic fertilizers become available to plants only as they become mineralized. That is, organic fertilizers have an aftereffect, since elements from them are used for 3-4 years.
• the efficiency of manure depends on climatic conditions and decreases from north to south and from west to east.
• application of organic fertilizers is a rather expensive undertaking - there are high costs for transportation, application of fuels and lubricants, depreciation and maintenance.

Litter manure- constituent parts - solid and liquid animal excrement and bedding. The chemical composition largely depends on the litter, its type and quantity, the type of animals, the feed consumed, and the storage method. Solid and liquid discharges of animals are unequal in composition and fertilizing qualities. Almost all of the phosphorus ends up in solid excretions, in liquid it is very little. About 1/2 - 2/3 of nitrogen and almost all potassium in feed are excreted in the urine of animals. N and P of solid excretions become available to plants only after their mineralization, while potassium is in a mobile form. All nutrients of liquid secretions are presented in readily soluble or light mineral form.

Litter- when added to manure, it increases its yield, improves its quality and reduces the loss of nitrogen and slurry in it. The following are used as bedding: straw, peat, sawdust, etc. During storage in manure, the processes of decomposition of solid excretions with the participation of microorganisms take place with the formation of simpler ones. Liquid secretions contain urea CO (NH2) 2, gipuric acid C6H5CONHCH2COOH and uric acid C5H4NO3, which can decompose to free NH3, two forms of N-protein and ammonia - there are no nitrates.

According to the degree of decomposition, fresh, semi-rotted, rotted and humus are distinguished.

Humus- rich in organic matter black homogeneous mass 25% of the original.

Application conditions - manure increases the yield for several years. In arid and extremely arid zones, the aftereffect outweighs the effect. The greatest effect of manure is achieved when it is introduced under autumn plowing, with immediate incorporation into the soil. The introduction of manure in winter leads to significant losses of NO3 and NH4 and its efficiency decreases by 40 - 60%. Fertilizer rates in crop rotation should be set taking into account the increase or maintenance of the humus content at the initial level. To do this, on chernozem soils, the saturation of 1 hectare of crop rotation should be 5 - 6 tons, on chestnut soils - 3 - 4 tons.

The dose of manure is 10 - 20 t / ha - arid, 20 - 40 tons - in insufficient moisture supply. Industrial crops are the most responsive - 25 - 40 t / ha. for winter wheat 20 - 25 t / ha under the predecessor.

Straw- an important source of organic fertilizers. The chemical composition of straw varies widely depending on soil and weather conditions. It contains about 15% H2O and about 85% consists of organic matter (celluluse, pengozans, hemocyllulose and gigin), which is a carbonaceous energy material for soil microorganisms, the basis of building material for the synthesis of humus. Straw contains 1-5% protein and only 3-7% ash. The organic matter of straw contains all the nutrients necessary for plants, which are mineralized by soil microorganisms into easily accessible forms in 1 g of straw, on average, it contains 4-7 N, 1-1.4 P2O5, 12-18 K2O, 2-3 kg of Ca , 0.8-1.2 kg Mg, 1-1.6 kg S, 5 g boron, 3 g Cu, 30 g Mn. 40 g Zn, 0.4 Mo, etc.

When evaluating straw as an organic fertilizer, not only the presence of certain substances is of great importance, but also the C: N ratio. It was found that for its normal decomposition the C: N ratio should be 20-30: 1.

The positive effect of straw on soil fertility and agricultural yield. crops is possible if the necessary conditions for its decomposition are present. The decomposition rate depends on: the availability of food sources for microorganisms, their number, species composition, soil type, its cultivation, temperature, humidity, aeration.

Slurry It is mainly fermented urine of animals for 4 months from 10 tons of bedding manure with dense storage, 170 liters are released, with loose-dense - 450 liters and with loose - 1000 liters. On average, slurry contains N-0.25 -0.3%, P2O5-0.03-0.06% and potassium - 0.4-0.5% - mainly nitrogen-potassium fertilizer. All nutrients in it are in a form readily available to plants, therefore it is considered fast-acting fertilizer... The utilization rate is 60-70% for N and K.

Bird droppings Is a valuable fast acting organic, concentrated fertilizer containing all the essential nutrients plants need. So in chicken poultry manure contains 1.6% N, 1.5 P2O5, 0.8% K2O, 2.4 CaO, 0.7 MgO, 0.4 SO2. In addition to trace elements, it includes trace elements, Mn, Zn, Co, Cu. The amount of nutrients in poultry manure is highly dependent on the feeding conditions of the poultry and the management of the poultry.

There are two main ways of keeping poultry: outdoor and cellular... For floor maintenance, a deep, non-replaceable bedding made of peat, straw, corn shafts is quite widely used. With the cage keeping of poultry, it is diluted with water, which reduces the concentration of nutrients and significantly increases the cost of using it as a fertilizer. Raw poultry manure is characterized by unfavorable physical properties that complicate the mechanization of use. It has a number of other negative properties: it spreads an unpleasant odor over long distances, contains a huge amount of weeds, a source of environmental pollution and a breeding ground for pathogenic microflora.

Green manure- fresh plant mass, plowed into the soil to enrich it with organic matter and nitrogen. This technique is often called green manure, and plants grown for fertilization are called green manure. Leguminous plants are cultivated as siderates in the South Russian steppe - seradella, sweet clover, mung bean, sainfoin, rank, vetch, winter and wintering peas, winter vetch, fodder peas (pelushka), astragalus; cabbage - winter and spring rape, mustard, as well as their mixtures with legumes. As the proportion of the legume component in the mixture decreases, the supply of nitrogen decreases, which is compensated for by a significantly larger amount of biological mass.

Green, like any organic fertilizer, has a multifaceted positive effect on the agrochemical properties of the soil and the yield of agricultural crops. Depending on the cultivation conditions, on each hectare of arable land, from 25 to 50 t / ha of green mass of green manure is grown and plowed. The biological mass of green fertilizers contains significantly less nitrogen and especially phosphorus and potassium in comparison with manure.

The introduction of fertilizers into the soil not only improves plant nutrition, but also changes the conditions for the existence of soil microorganisms, which also require mineral elements.

Under favorable climatic conditions, the number of microorganisms and their activity after fertilization of the soil increases significantly. The decay of humus intensifies, and as a result, the mobilization of nitrogen, phosphorus and other elements increases.

There was a point of view that long-term use of mineral fertilizers leads to a catastrophic loss of humus and deterioration of the physical properties of the soil. However, experimental data did not confirm it. Thus, on the sod-podzolic soil of the TSKhA, Academician D.N.Pryanishnikov laid an experiment with a different fertilization system. On the plots where mineral fertilizers were applied, on average 36.9 kg of nitrogen, 43.6 kg of P205 and 50.1 kg of K2O per 1 ha were applied per year. In the soil fertilized with manure, it was applied annually at 15.7 t / ha. After 60 years, a microbiological analysis of the experimental plots was carried out.

Thus, for 60 years, the humus content in the fallow soil has decreased, but in the fertilized soils, its losses were less than in the unfertilized one. This can be explained by the fact that the introduction of mineral fertilizers promoted the development of autotrophic microflora (mainly algae) in the soil, which led to some accumulation of organic matter in the steaming soil, and, consequently, humus. Manure is a direct source of humus formation, the accumulation of which under the influence of this organic fertilizer is quite understandable.

On plots with the same fertilizer, but occupied by agricultural crops, fertilizers worked even more favorably. Stubble and root residues here activated the activity of microorganisms and compensated for the consumption of humus. The control soil in the crop rotation contained 1.38% of humus, receiving NPK-1.46, and the fertilized soil-1.96%.

It should be noted that in fertilized soils, even those that received manure, the content of fulvic acids decreases and the content of less mobile fractions increases relatively.

In general, mineral fertilizers stabilize humus levels to a greater or lesser extent, depending on the amount of crop and root residues left behind. Manure rich in humus further enhances this stabilization process. If manure is applied in large quantities, then the humus content in the soil increases.

The data of the Rothamsted Experimental Station (England), where long-term studies (about 120 years) were carried out with a monoculture of winter wheat, are very indicative. In the soil that did not receive fertilizers, the humus content decreased slightly.

With an annual application of 144 kg of mineral nitrogen with other mineral substances (P 2O 5, K 2O, etc.), a very slight increase in the humus content was noted. A very significant increase in the humus content of soils took place with an annual introduction of 35 tons of manure per hectare into the soil (Fig. 71).

The introduction of mineral and organic fertilizers into the soil increases the intensity of microbiological processes, resulting in a concomitant increase in the transformation of organic and mineral substances.

The experiments carried out by FV Turchin showed that the application of nitrogen-containing mineral fertilizers (labeled with 15N) increases the yield of plants not only as a result of fertilizing action, but also due to the better utilization of nitrogen from the soil by plants (Table 27). In the experiment, 420 mg of nitrogen was added to each vessel containing 6 kg of soil.

With an increase in the dose of nitrogen fertilizers, the proportion of soil nitrogen used increases.

A characteristic indicator of the activation of the activity of microflora under the influence of fertilizers is an increase in the "respiration" of the soil, that is, the release of CO2 by it. This is the result of accelerated decomposition of organic soil compounds (including humus).

The introduction of phosphorus-potassium fertilizers into the soil does little to promote the use of soil nitrogen by plants, but enhances the activity of nitrogen-fixing microorganisms.

The information presented allows us to conclude that, in addition to the direct effect on plants, nitrogen fertilizers also have a large indirect effect - they mobilize soil nitrogen

(obtaining "extra nitrogen"). In humus-rich soils, this indirect effect is much greater than the direct one. This affects the overall efficiency of mineral fertilizers. The generalization of the results of 3500 experiments with grain crops carried out in the Non-Black Earth zone of the European part of the CIS, made by A.P. Fedoseev, showed that the same doses of fertilizers (NPK 50-100 kg / ha) give significantly higher yield increases on fertile soils than on poor ones. soils: respectively 4.1; 3.7 and 1.4 c / ha on highly, medium and poorly cultivated soils.

It is very important that high doses of nitrogen fertilizers (about 100 kg / ha and more) are effective only on highly cultivated soils. On low-fertile soils, they usually act negatively (Fig. 72).

Table 28 summarizes the data of GDR scientists on nitrogen consumption to obtain 1 centner of grain on different soils. As you can see, mineral fertilizers are most economically used on soils containing more humus.

Thus, to obtain high yields, it is necessary not only to fertilize the soil with mineral fertilizers, but also to create a sufficient supply of nutrients for plants in the soil itself. This is facilitated by the introduction of organic fertilizers into the soil.

Sometimes the introduction of mineral fertilizers into the soil, especially in high doses, has an extremely unfavorable effect on its fertility. This is usually observed on low-buffer soils when using physiologically acidic fertilizers. When the soil is acidified, aluminum compounds pass into the solution, which have a toxic effect on soil and plant microorganisms.

The unfavorable effect of mineral fertilizers was observed on light, marginal sandy and sandy loam podzolic soils of the Solikamsk Agricultural Experimental Station. One of the analyzes of the differently fertilized soil at this station is shown in Table 29.

In this experiment, N90, P90, K120 were added to the soil annually, and manure was added 2 times in three years (25 t / ha). Based on the total hydrolytic acidity, lime was given (4.8 t / ha).

The use of NPK for a number of years has significantly reduced the number of microorganisms in the soil. Only microscopic fungi were not affected. The introduction of lime, and especially lime with manure, had a very beneficial effect on the saprophytic microflora. By changing the reaction of the soil in a favorable direction, lime neutralized the harmful effect of physiologically acidic mineral fertilizers.

After 14 years, yields with the introduction of mineral fertilizers actually decreased to zero as a result of strong acidification of the soil. The use of liming and manure helped to normalize the pH of the soil and obtain a harvest that is sufficiently high for the specified conditions. In general, the microflora of the soil and plants reacted to changes in the soil background in about the same way.

The generalization of a large amount of material on the use of mineral fertilizers in the CIS (I. V. Tyurin, A. V. Sokolov, and others) allows us to conclude that their influence on the yield is associated with the zonal position of soils. As already noted, in the soils of the northern zone, microbiological mobilization processes proceed slowly. Therefore, there is a stronger deficit of basic nutrients for plants, and mineral fertilizers are more effective than in the southern zone. This, however, does not contradict the above statement about the best effect of mineral fertilizers on highly cultivated backgrounds in individual soil and climatic zones.

Let's briefly dwell on the use of microfertilizers. Some of them, for example, molybdenum, are included in the enzyme system of nitrogen-fixing microorganisms. For symbiotic nitrogen fixation

boron is also necessary, which ensures the formation of a normal vascular system in plants, and, consequently, the successful course of the nitrogen assimilation process. Most of the other microelements (Cu, Mn, Zn, etc.) in small doses increases the intensity of microbiological processes in the soil.

It has been shown that organic fertilizers, especially manure, have a very favorable effect on the soil microflora. The rate of mineralization of manure in soil is determined by a number of factors, but under other favorable conditions it depends mainly on the ratio of carbon to nitrogen (C: N) in manure. Usually, manure causes an increase in yield within 2-3 years, in contrast to. nitrogen fertilizers that have no aftereffect. Semi-rotted manure with a narrower C: N ratio exhibits a fertilizing effect from the moment of its application, since it does not have a carbon-rich material that causes vigorous absorption of nitrogen by microorganisms. In rotted manure, a significant part of nitrogen is converted into humus, which is poorly mineralized. Therefore, manure - powder as nitrogen fertilizer has a smaller, but lasting effect.

These features apply to composts and other organic fertilizers. Taking them into account, it is possible to create organic fertilizers that act at certain stages of plant development.

Green fertilizers, or green manures, are also widely used. These are organic fertilizers plowed into the soil; they mineralize more or less quickly depending on soil and climatic conditions.

Recently, great attention has been paid to the use of straw as an organic fertilizer. The introduction of straw could enrich the soil with humus. In addition, straw contains about 0.5% nitrogen and other elements necessary for plants. When straw decomposes, a lot of carbon dioxide is released, which also has a beneficial effect on crops. Back at the beginning of the 19th century. the English chemist J. Devi pointed out the possibility of using straw as an organic fertilizer.

However, until recently, it was not recommended to plow the straw. This was justified by the fact that straw has a wide C: N ratio (about 80: 1) and its incorporation into the soil causes the biological fixation of mineral nitrogen. Plant materials with a narrower C: N ratio do not cause this phenomenon (Fig. 73).

Plants sown after plowing straw are deficient in nitrogen. The only exceptions are legumes, which provide themselves with nitrogen with the help of nodule bacteria fixing molecular nitrogen of the culture, which provide themselves with nitrogen with the help of nodule bacteria fixing molecular nitrogen.

The lack of nitrogen after incorporating the straw can be compensated for by applying nitrogen fertilizers at the rate of 6-7 kg of nitrogen per 1 ton of plowed straw. At the same time, the situation is not completely corrected, since the straw contains some substances that are toxic to plants. It takes a certain period of time for their detoxification, which is carried out by microorganisms that decompose these compounds.

The experimental work carried out in recent years makes it possible to give recommendations for eliminating the unfavorable effect of straw on agricultural crops.

In the conditions of the northern zone, it is advisable to plow the straw in the form of cutting into the upper layer of the soil. Here, under aerobic conditions, all substances toxic to plants decompose rather quickly. With shallow plowing, after 1-1.5 months, the destruction of harmful compounds occurs and biologically fixed nitrogen begins to be released. In the south, especially in subtropical and tropical zones, the time gap between straw incorporation and sowing can be the smallest, even with deep plowing. Here all unfavorable moments disappear very quickly.

If these recommendations are followed, the soil is not only enriched with organic matter, but also mobilization processes are activated in it, including the activity of nitrogen-fixing microorganisms. Depending on a number of conditions, the introduction of 1 ton of straw leads to the fixation of 5-12 kg of molecular nitrogen.

Now, on the basis of numerous field experiments carried out in our country, the expediency of using excess straw as an organic fertilizer has been fully confirmed.

Kuban State University

Department of Biology

on the discipline "Soil Ecology"

"Latent negative effect of fertilizers."

Performed

Afanasyeva L. Yu.

5th year student

(speciality -

"Bioecology")

Checked by O. V. Bukareva

Krasnodar, 2010

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

1. The effect of mineral fertilizers on soils ………………………………… ... 4

2. Influence of mineral fertilizers on atmospheric air and water ………… ..5

3. Influence of mineral fertilizers on product quality and human health ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

4. Geoecological consequences of fertilization …………………… ... 8

5. Impact of fertilizers on the environment …………………………… ..10

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

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

Introduction

Soil pollution with foreign chemicals causes great damage to them. Chemicalization of agriculture is a significant factor of environmental pollution. Even mineral fertilizers, if used incorrectly, can cause environmental damage with a dubious economic effect.

Numerous studies of agricultural chemists have shown that different types and forms of mineral fertilizers have different effects on the properties of soils. Fertilizers applied to 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. The transformation of certain types of mineral fertilizers (phosphorus, potash, nitrogen) determines their effect on soil fertility.

Mineral fertilizers are an inevitable consequence of intensive farming. There are calculations that in order to achieve the desired effect from the use of mineral fertilizers, their world consumption should be about 90 kg / year per person. The total production of fertilizers in this case reaches 450-500 million tons / year, while at the present time their world production is equal to 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 input per unit of agricultural production. This means that more and more mineral fertilizers are required to obtain the same yield increase. So, at the initial stages of the application of fertilizers, the addition of 1 ton of grain from 1 hectare is provided by the introduction of 180-200 kg of nitrogen fertilizers. The next additional ton of grain is associated with a 2-3 times higher fertilizer dose.

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

The local impact of fertilizers on ecosystems and soils into which they are applied.

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

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

1. Influence of mineral fertilizers on soil

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

Acidity rises;

The species composition of soil organisms is changing;

The circulation of substances is disrupted;

The structure is destroyed, impairing other properties.

There is evidence (Mineev, 1964) that an increase in soil acidity when using fertilizers (primarily acidic nitrogen fertilizers) results in increased leaching of calcium and magnesium from them. To neutralize this phenomenon, these elements have to be introduced into the soil.

Phosphate fertilizers do not have such a pronounced acidifying effect as nitrogen fertilizers, 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 and lead to a progressive accumulation of heavy metals. The main way reduce these consequences- moderate and scientifically sound fertilization:

Optimal doses;

The minimum amount of harmful impurities;

Alternating with organic fertilizers.

It should also be remembered that "mineral fertilizers are a means of masking realities." Thus, there is evidence that more minerals are removed with the products of soil erosion than they are introduced with fertilizers.

2. Influence of mineral fertilizers on atmospheric air and water

The effect of mineral fertilizers on atmospheric air and water is mainly associated with their nitrogen forms. The nitrogen of mineral fertilizers 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 N2O).

According to modern concepts, gaseous nitrogen losses from nitrogen fertilizers amount to 10 to 50% of its application. An effective means of reducing gaseous nitrogen losses is their scientifically sound application:

Application to the root-forming zone for the fastest absorption by plants;

Use of substances that inhibit gaseous losses (nitropyrine).

The most noticeable effect on water sources, in addition to nitrogen, is exerted by phosphorus fertilizers. Fertilizer carry-over to water sources is minimized when applied correctly. In particular, it is unacceptable to spread fertilizers over the snow cover, scatter them from aircraft near water bodies, or store them in the open air.

3. Influence of mineral fertilizers on product quality and human health

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

With high doses of nitrogen fertilizers, the risk of plant diseases increases. Excessive accumulation of green mass takes place, and the likelihood of lodging of plants sharply increases.

Many fertilizers, especially those containing chlorine (ammonium chloride, potassium chloride), have a negative effect on animals and humans, mainly through the water, where the released chlorine enters.

The negative effect of phosphorus fertilizers is mainly due to the fluorine, heavy metals and radioactive elements they contain. Fluoride, when its concentration in water is more than 2 mg / l, can contribute to the destruction of tooth enamel.

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

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

4. Geoecological consequences of fertilization

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

In natural ecosystems, the rate of accumulation or consumption of nutrients is usually low. For example, for the virgin steppe on the chernozems of the Russian Plain, the ratio between the flux of nitrogen compounds across the boundaries of the selected area of ​​the steppe and its reserves in the upper meter layer is about 0.0001% or 0.01%.

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

In total, with the grain harvest in the world, for example, about 40 million tons of nitrogen is removed per year, or about 63 kg per hectare of grain. Hence, it is necessary to use fertilizers to maintain soil fertility and increase yields, since with intensive farming without fertilizers, soil fertility decreases already in the second year. Usually nitrogen, phosphorus and potash fertilizers are 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 over 1950-1990. approximately 10 times. The world average use of fertilizers in 1993 was 83 kg per hectare of arable land. Hidden behind this average is a large difference in the consumption of different countries. The Netherlands uses the most fertilizers, and there the level of fertilization has even decreased 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 24 countries using 5 kg / ha or less.

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

Nitrates are hazardous to human health if their concentration in drinking water or agricultural products is higher than the established MPC. The concentration of nitrates in 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 and duration of fertilizer application increases, more and more nitrates enter surface and groundwater, making them unsuitable for drinking. If the level of application of nitrogen fertilizers does not exceed 150 kg / ha per year, then about 10% of the volume of applied fertilizers gets into natural waters. At higher loads, this proportion is even higher.

In particular, the problem of groundwater pollution after nitrates has entered the aquifer is a serious problem. Water erosion, carrying away soil particles, also transfers phosphorus and nitrogen compounds contained in them and adsorbed on them. If they enter water bodies with slow water exchange, the conditions for the development of the eutrophication process are improved. For example, dissolved and suspended nutrient compounds have become the main water pollutants in the rivers of the United States.

Agricultural dependence on mineral fertilizers has led to major shifts in global nitrogen and phosphorus cycles. The industrial production of nitrogen fertilizers has disrupted the global nitrogen balance due to a 70% increase in the amount of nitrogen compounds available to plants compared to the pre-industrial period. Excessive 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 deterioration of natural water quality.

According to scientists, the washout 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, the same amount of phosphorus was carried by rivers into the ocean as it was introduced into the fields, namely 33 million tons. Since there are no gaseous compounds of phosphorus, it moves under the influence of gravity, mainly with water, mainly from continents to the oceans ... This leads to a chronic deficiency of phosphorus on land and to another global geo-ecological crisis.

5. Impact of fertilizers on the environment

The negative effect of fertilizers on the environment is associated, first of all, with the imperfection of the properties and chemical composition of fertilizers. Substantial disadvantages of many mineral fertilizers are:

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

Physiological acidity and alkalinity resulting from the predominant use of cations or anions by plants from fertilizers. 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 protein photo- and biosynthesis, fruit development. Increased doses of fluorine inhibit the development of animals and lead to poisoning.

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

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

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

Soluble in soil phosphate fertilizers are largely absorbed by the soil and become inaccessible to plants and do not move along the soil profile. It was found that the first crop uses only 10-30% of P2 O5 from phosphorus fertilizers, and the rest remains in the soil and undergoes all kinds of transformations. For example, in acidic soils, the phosphorus of superphosphate is mostly converted into iron and aluminum phosphates, and in chernozem and in all calcareous soils - into insoluble calcium phosphates. The systematic and long-term use of phosphorus fertilizers is accompanied by the gradual cultivation of the soil.

It is known that long-term use of large doses of phosphorus fertilizers can lead to the so-called "phosphating", when the soil is enriched with assimilable phosphates and new portions of fertilizers have no effect. In this case, excess phosphorus in the soil can disrupt the nutrient ratio and sometimes reduce the availability of zinc and iron to plants. So, in the conditions of Krasnodar Territory on ordinary carbonate chernozems with ordinary application of P2 O5, corn unexpectedly sharply reduced the yield. We had to find ways to optimize the elemental nutrition of plants. Phosphating of soils is a certain stage of their domestication. 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 from the crop.

As a rule, this "residual" phosphorus fertilizer is more mobile and more accessible to plants than natural soil phosphates. With the systematic and long-term 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 fertilizer added to the soil, like phosphorus, does not remain unchanged. Part of it is in the soil solution, part goes into an absorbed-exchange state, and part turns into a non-exchangeable form that is inaccessible to plants. The accumulation of available forms of potassium in the soil, as well as the transformation into an inaccessible state as a result of prolonged use of potash fertilizers, depends mainly on the properties of the soil and weather conditions. So, in chernozem soils, the amount of assimilable forms of potassium under the influence of fertilization increases, but to a lesser extent than on sod-podzolic soils, since in chernozems, potassium of fertilizers is more converted into a non-exchangeable form. In an area with a large amount of precipitation and with irrigated agriculture, it is possible for potassium fertilizers to be washed out of the root layer of the soil.

In areas with insufficient moisture, in hot climates, where soils periodically moisten and dry out, there are intense processes of fixation of potassium fertilizers by the soil. Under the influence of the fixation of potassium fertilizers passes into a non-exchangeable state inaccessible to plants. The type of soil minerals and the presence of minerals with a high fixing ability are of great importance for the degree of potassium fixation by soils. These are clay minerals. Chernozems have a greater ability to fix potassium fertilizers than sod-podzolic soils.

Soil alkalinization caused by the addition of lime or natural carbonates, especially soda, increases fixation. The fixation of potassium depends on the dose of fertilizer: with an increase in the dose of applied fertilizers, the percentage of fixation of potassium decreases. In order to reduce the fixation of fertilizers potassium by soils, it is recommended to apply potassium fertilizers to a sufficient depth to prevent drying out and to apply them more often in crop rotation, since soils systematically fertilized with potassium fix it weaker with a new addition. But the fixed potassium of fertilizers, which is in a non-exchangeable state, also participates in plant nutrition, since over time it can pass into an exchange-absorbed state.

Nitrogen fertilizers in terms of interaction with soil, they differ significantly 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 nitrification they acquire the properties of nitrate fertilizers. Partially ammonia can be absorbed by the soil without exchange. Non-exchangeable, fixed ammonium is available to plants to a small extent. In addition, the loss of nitrogen in fertilizers from the soil is possible as a result of nitrogen volatilization in free form or in the form of nitrogen oxides. When nitrogen fertilizers are applied, the content of nitrates in the soil changes sharply, since the compounds that are most easily assimilated by plants come with fertilizers. The dynamics of nitrates in the soil to a greater extent characterizes its fertility.

A very important property of nitrogen fertilizers, especially ammonia, 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 more quickly, transforming into forms readily available for plants.

Some nutrients, especially nitrogen in the form of nitrates, chlorides and sulfates, can seep 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 the fish industry. The 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 fertilizers used.

In the soils of the Krasnodar Territory with a periodically flushed water regime, nitrates are found to a depth of 10 m and more and merge with groundwater. This indicates a periodic deep migration of nitrates and their inclusion in the biochemical cycle, the initial links of which are soil, parent rock, and groundwater. Such a migration of nitrates can be observed in wet years, when the soils are characterized by a leaching water regime. It was during these years that the danger of nitrate pollution of the environment arises when large doses of nitrogen fertilizers are applied before winter. In years with a non-flush water regime, the supply of nitrates to the groundwater completely stops, although residual traces of nitrogen compounds are observed along the entire profile of the source rock to the groundwater. Their preservation is facilitated by the low biological activity of this part of the weathering crust.

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

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

Plants tend to accumulate in their organisms nitrates contained in the soil in excess quantities. The yield of plants is growing, but the products are poisoned. Vegetable crops, watermelons and melons accumulate nitrates especially intensively.

In Russia, MPCs for plant nitrates are adopted (Table 3). The permissible daily intake (ADI) for a person is 5 mg per 1 kg of body weight.

Table 3 - Acceptable levels of nitrates in foods

vegetable origin, mg / kg

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, combining with blood hemoglobin, convert 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.

New ways to reduce the loss of nutrients and limit their pollution of the environment :

To reduce nitrogen losses from fertilizers, slow-acting nitrogen fertilizers and nitrification inhibitors, films, additives are recommended; the encapsulation of fine-grained fertilizers with shells of sulfur and plastics is introduced. The even 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 for 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 substantiated methods, timing, and rates of their application without taking into account the properties of the soil.

The hidden negative effect of fertilizers can manifest itself by its effect on the soil, plants, environment. When compiling a calculation algorithm, the following processes must be taken into account:

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

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

3. Deterioration of soil water properties. 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. Decrease in the intake of substances into plants, competition for absorption by the root, toxicity, change in the charge of the root and root zone. As ways to eliminate negative consequences, a balanced fertilizer system is used; foliar feeding of plants.

5. Manifestation of imbalance in root systems, violation of metabolic cycles.

6. The appearance of imbalance in the leaves, disruption of metabolic cycles, deterioration of technological and taste qualities.

7. Toxicity of microbiological activity. As ways to eliminate 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 world of the soil. As ways to eliminate negative consequences, a balanced fertilizer system is used; increase in soil buffering.

10. Reducing adaptation to pests and diseases, extreme conditions, due to overfeeding. As measures to eliminate negative consequences, it is recommended to optimize the ratio of nutrients; regulation of fertilizer doses; integrated plant protection system; the use of foliar feeding.

11. Losses of humus, changes in its fractional composition. To eliminate the negative consequences, the application of organic fertilizers, the creation of a structure, the optimization of pH, the regulation of the water regime, and the balance of the fertilizer system are used.

12. Deterioration of the physical and chemical properties of soils. Ways of elimination - optimization of the fertilizer system, the introduction of ameliorants, organic fertilizers.

13. Deterioration of the physical and mechanical properties of soils.

14. 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 the soil structure.

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

16. The emergence of toxic concentrations of individual elements. To reduce the negative impact, it is necessary to balance the fertilizer system, increase the buffer capacity of soils, precipitation and removal of individual elements, and complexation.

17. Increase in the concentration of individual elements in plants above the permissible level. It is necessary to reduce fertilizer rates, balance the fertilizer system, foliar top dressing in order to compete with the intake of toxicants into plants, and introduce antagonists of toxicants into the soil.

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

Unbalanced use of various fertilizers;

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

Directed selection of fertilizer forms for certain types of soil, plants and environmental conditions;

Incorrect timing of fertilization for specific soils and environmental conditions;

The introduction of various toxicants along with fertilizers and ameliorants and their gradual accumulation in the soil 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 makes it possible to radically solve the problem of food and agricultural raw materials. Agriculture is now unthinkable without the use of fertilizers.

With proper organization and control of application, mineral fertilizers are not hazardous to the environment, human and animal health. The optimal scientifically based doses increase the yield of plants and increase the amount of production.

Conclusion

Every year, the agro-industrial complex more and more resorts 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 farmers, ecologists and doctors around the world question the excessive enthusiasm for biochemical novelties that have literally occupied the market today. Fertilizer manufacturers describe the advantages of their own invention, without mentioning that improper or excessive fertilization can have a detrimental effect on the soil.

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

List of used literature

1. Akimova TA, Khaskin VV Ecology. Human - Economy - Biota - Environment. - M., 2001

2. Valkov VF, Shtompel Yu. A., Tyulpanov VI Soil science (soils of the North Caucasus). - Krasnodar, 2002.

3. Golubev GN Geoecology. - M, 1999.

The influence of mineral fertilizers on soil microorganisms and its fertility. The introduction of fertilizers into the soil not only improves plant nutrition, but also changes the conditions for the existence of soil microorganisms, which also require mineral elements.

Under favorable climatic conditions, the number of microorganisms and their activity after the introduction of fertilizers into the soil increases significantly. The decay of humus intensifies, the mobilization of nitrogen, phosphorus and other elements increases.

After the application of mineral fertilizers, the activity of bacteria is activated. In the presence of mineral nitrogen, humus decomposes more easily and is used by microorganisms. The introduction of mineral fertilizers causes a slight decrease in the number of actinomycetes and an increase in the fungal population, which may be a consequence of a shift in the reaction of the environment to the acidic side as a result of the introduction of physiologically acidic salts: actinomycetes do not tolerate acidification well, and the reproduction of many fungi is accelerated in a more acidic environment.

Mineral fertilizers, although they activate the activity of microorganisms, reduce the loss of humus and stabilize the level of humus, depending on the amount of stubble and root residues left.

The introduction of mineral and organic fertilizers into the soil increases the intensity of microbiological processes, resulting in a concomitant increase in the transformation of organic and mineral substances.

A characteristic indicator of the activation of microbial activity under the influence of fertilizers is the intensification of the "respiration" of the soil, that is, the release of CO2 by it. This is the result of accelerated decomposition of organic soil compounds, including humus.

The introduction of phosphorus-potassium fertilizers into the soil does little to promote the use of soil nitrogen by plants, but enhances the activity of nitrogen-fixing microorganisms.

Sometimes the introduction of mineral fertilizers into the soil, especially in high doses, adversely affects its fertility. This is usually observed on low-buffer soils when using physiologically acidic fertilizers. When the soil is acidified, aluminum compounds that are toxic to soil and plant microorganisms pass into the solution.

The introduction of lime, especially together with manure, has a beneficial effect on the saprotrophic microflora. By changing the pH of the soil in a favorable direction, lime neutralizes the harmful effect of physiologically acidic mineral fertilizers.

The influence of mineral fertilizers on the yield is associated with the zonal position of the soils. As already noted, in the soils of the northern zone, microbiological mobilization processes proceed slowly. Therefore, in the north, there is a stronger deficit of basic nutrients for plants, and mineral fertilizers, even in small doses, are more effective than in the southern zone. This does not contradict the well-known thesis about the best effect of mineral fertilizers against the background of high soil cultivation.