The effect of fertilizers on the soil. The effect of mineral fertilizers on seedlings

Kuban State University

Department of Biology

in the discipline "Soil Ecology"

"The hidden negative effect of fertilizers".

Performed

Afanasyeva L. Yu.

5th year student

(speciality -

"Bioecology")

Checked Bukareva O.V.

Krasnodar, 2010

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

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

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

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

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

Pollution of soils with foreign chemicals causes great damage to them. A significant factor in environmental pollution is the chemicalization of agriculture. 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 affect soil properties in different ways. Fertilizers introduced into the soil enter into complex interactions with it. All sorts of transformations take place here, which depend on a number of factors: the properties of fertilizers and soil, weather conditions, and agricultural technology. From how the transformation 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. 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 present their world 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 input per unit of agricultural output. This means that in order to obtain the same increase in yield, an increasing amount of mineral fertilizers is required. So, at the initial stages of fertilizer application, an increase of 1 ton of grain per 1 ha ensures the introduction of 180-200 kg of nitrogen fertilizers. The next additional ton of grain is associated with a dose of fertilizer 2-3 times greater.

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

Local impact of fertilizers on ecosystems and soils to which they are applied.

Outrageous 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. Effect of mineral fertilizers on soils

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

Increases acidity;

The species composition of soil organisms is changing;

The circulation of substances is disrupted;

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 the increase in soil acidity with the use of fertilizers (primarily acidic nitrogen fertilizers). To neutralize this phenomenon, these elements have to be introduced into the soil.

Phosphorus 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 foreign impurities. In particular, their introduction can increase the radioactive background and lead to progressive accumulation of heavy metals. Basic way reduce these effects.– moderate and scientifically based use of fertilizers:

Optimal doses;

The minimum amount of harmful impurities;

Alternate with organic fertilizers.

You should also remember the expression 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 applied with fertilizers.

2. Effect of mineral fertilizers on atmospheric air and water

The influence of mineral fertilizers on atmospheric air and water is mainly associated with their nitrogen forms. Nitrogen from 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 losses of nitrogen from nitrogen fertilizers range from 10 to 50% of its application. An effective means of reducing gaseous losses of nitrogen is their scientifically substantiated application:

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

The use of substances-inhibitors of gaseous losses (nitropyrin).

The most tangible impact on water sources, in addition to nitrogen, is phosphorus fertilizers. Carryover of fertilizers into water sources is minimized when applied correctly. In particular, it is unacceptable to spread fertilizers on the snow cover, disperse them from aircraft near water bodies, and store them in the open.

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

Mineral fertilizers can have a negative impact both on plants and on the quality of plant products, as well as on the organisms that consume them. The main of these impacts 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 probability of plant lodging increases sharply.

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

The negative effect of phosphate fertilizers is mainly due to the fluorine, heavy metals and radioactive elements contained in them. Fluorine at its concentration in water 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

Types of fertilizers	The influence 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 morbidity, especially 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; help to increase the resistance of plants to diseases.	At high doses, toxicosis of plants is possible. They act mainly through the heavy metals contained in them (cadmium, arsenic, selenium), radioactive elements and fluorine. The main accumulators are parsley, onion, sorrel.
Potash	Similar to phosphorus.	They act mainly through the accumulation of chlorine when making potassium chloride. With an excess of potassium - toxicosis. The main accumulators of potassium are potatoes, grapes, buckwheat, greenhouse vegetables.

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

Types of fertilizers	Main Impacts
Nitrate forms	Nitrates (maximum concentration limit for water 10 mg/l, for food - 500 mg/day per person) are reduced in the body to nitrites, which cause 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, loss of eyelashes, rupture of the alveoli. In animal husbandry: beriberi, reduced productivity, accumulation of urea in milk, increased morbidity, reduced fertility.
Phosphoric Superphosphate	They act mainly through fluorine. Its excess in drinking water (more than 2 mg / l) causes damage to the enamel of teeth in humans, loss of elasticity of blood vessels. At a content of more than 8 mg / l - osteochondrosis phenomena.
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 fertilizer application

For their development, plants need a certain amount of nutrients (compounds of nitrogen, phosphorus, potassium), usually absorbed from the soil. In natural ecosystems, nutrients assimilated by vegetation return to the soil as a result of degradation processes in the cycle of matter (decomposition of fruits, plant litter, dead shoots, roots). A certain amount of nitrogen compounds is fixed by bacteria from the atmosphere. Part of the biogens is introduced with precipitation. On the negative side of the balance are infiltration and surface runoff of soluble compounds of biogens, their removal with soil particles in the process of 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 flow of nitrogen compounds through 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 some 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 intensity of removal. Therefore, 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 are removed per year, or approximately 63 kg per 1 ha of grain area. 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 by 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. about 10 times. The average world use of fertilizers in 1993 was 83 kg per 1 ha of arable land. Behind this average is a large difference in the consumption of different countries. The Netherlands uses the most fertilizers, and there the level of fertilizer application has even decreased in recent years: from 820 kg/ha to 560 kg/ha. On the other hand, 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 create 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 fields is usually between 1 and 10 mg/l, and from unploughed land it is an order of magnitude lower. As the mass and duration of fertilizer use increases, more and more nitrates enter surface and groundwater, making them undrinkable. If the level of application of nitrogen fertilizers does not exceed 150 kg/ha per year, then approximately 10% of the volume of applied fertilizers gets into natural waters. At a higher load, this proportion is even higher.

In particular, the problem of groundwater pollution after nitrates have entered the aquifer is serious. Water erosion, carrying away soil particles, also transfers the compounds of phosphorus and nitrogen 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 improve. So, in the rivers of the United States, dissolved and suspended compounds of biogens have become the main water pollutant.

The dependence of agriculture on mineral fertilizers has led to major shifts in the global cycles of nitrogen and phosphorus. The industrial production of nitrogen fertilizers has led to a disruption in the global nitrogen balance due to an increase in the amount of nitrogen compounds available to plants by 70% compared to the pre-industrial period. Too much nitrogen can change soil acidity as well as soil organic matter content, which can further leach soil nutrients and degrade 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, as much phosphorus was carried by rivers into the ocean as was introduced into the fields, namely 33 million tons. Since gaseous phosphorus compounds do not exist, it moves under the influence of gravity, mainly with water, mainly from continents to oceans . This leads to a chronic lack of phosphorus on land and to another global geoecological crisis.

5. Environmental impact of fertilizers

The negative effect of fertilizers on the environment is primarily due to the imperfection of the properties and chemical composition of fertilizers. significant 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 humus losses, increases the mobility and migration of many elements.

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

The presence of heavy metals (cadmium, lead, nickel). Phosphoric and complex fertilizers are the 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 phosphate and complex fertilizers leads to environmental pollution with fluorine and arsenic compounds.

With the existing acid 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 content of fluorine in superphosphate reaches 1-1.5, in ammophos 3-5%. On average, with each ton of phosphorus necessary for plants, about 160 kg of fluorine enters the fields.

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

Soluble applied to the soil phosphate fertilizers are largely absorbed by the soil and become inaccessible to plants and do not move along the soil profile. It has been established that the first crop uses only 10-30% of P2O5 from phosphate 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 all carbonate soils, into insoluble calcium phosphates. The systematic and long-term use of phosphorus fertilizers is accompanied by the gradual cultivation of soils.

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, an excess of phosphorus in the soil can upset the ratio between nutrients and sometimes reduce the availability of zinc and iron to plants. Thus, in the conditions of the Krasnodar Territory on ordinary carbonate chernozems with the usual application of P2O5, corn unexpectedly sharply reduced the yield. We had to find ways to optimize the elemental nutrition of plants. Soil phosphating is a certain stage of their cultivation. This is the result of the inevitable accumulation of "residual" phosphorus, when fertilizers are applied in an amount that exceeds the carry-over of phosphorus with the crop.

As a rule, this “residual” phosphorus in the fertilizer is more mobile and available to plants than natural soil phosphates. With the systematic and long-term application of these fertilizers, it is necessary to change the ratios 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, introduced into 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-exchange, inaccessible form for plants. The accumulation of available forms of potassium in the soil, as well as the transformation into an inaccessible state as a result of long-term use of potassium fertilizers, depends mainly on soil properties and weather conditions. So, in chernozem soils, the amount of assimilable forms of potassium under the influence of fertilizer, although it increases, but to a lesser extent than on soddy-podzolic soils, since in chernozem fertilizer potassium is more converted into a non-exchangeable form. In a zone with a large amount of precipitation and during irrigated agriculture, potassium fertilizers may be washed out of the root layer of the soil.

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

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

nitrogen fertilizers on interaction with the soil significantly differ from phosphorus and potash. Nitrate forms of nitrogen are not absorbed by the soil, so they can easily be washed out by 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 without exchange. Non-exchangeable, fixed ammonium is available to plants to a small extent. In addition, the loss of fertilizer nitrogen 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 compounds most easily absorbed 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, soil organic compounds are more quickly mineralized and converted into forms that are easily accessible to plants.

Some nutrients, especially nitrogen in the form of nitrates, chlorides and sulfates, can enter 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. The migration of nutrients from soils to groundwater in different soil and climatic conditions is not the same. In addition, it depends on the types, forms, doses and terms of fertilizers used.

In the soils of the Krasnodar Territory with a periodically leaching water regime, nitrates are found to a depth of 10 m or 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 migration of nitrates can be observed in wet years, when soils are characterized by a leaching water regime. It is 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-leaching water regime, the entry of nitrates into groundwater completely stops, although residual traces of nitrogen compounds are observed along the entire profile of the parent rock to groundwater. Their preservation is facilitated by the low biological activity of this part of the weathering crust.

In soils with a non-leaching 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 harmful potential impact of nitrogen applied with fertilizers can be minimized by maximizing the use of nitrogen by crops. So, care must be taken that with an increase in the doses of nitrogen fertilizers, the efficiency of using their nitrogen by plants increases; there was not a large amount of nitrates unused by plants, which are not retained by soils and can be washed out by precipitation from the root layer.

Plants tend to accumulate in their bodies 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 nitrates of plant origin have been adopted (Table 3). The permissible daily dose (ADD) for a person is 5 mg per 1 kg of body weight.

Table 3 - Permissible levels of nitrate content in products

vegetable origin, mg/kg

Product	Priming
open	protected
Potato
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, combining with blood hemoglobin, convert it to methemoglobin, which prevents the transfer of oxygen through the circulatory system; a disease develops - methemoglobinemia, especially dangerous for children. Symptoms of the disease: fainting, vomiting, diarrhea.

New ways to reduce nutrient losses 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 with shells of sulfur and plastics is introduced. The uniform release of nitrogen from these fertilizers eliminates the accumulation of nitrates in the soil.

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

Separate facts of the negative impact of fertilizers on the environment are associated with errors in the practice of their application, with insufficiently substantiated methods, terms, rates of their application without taking into account soil properties.

The hidden negative effect of fertilizers can be manifested by its effect on the soil, plants, and the environment. When compiling the calculation algorithm, the following processes should be taken into account:

1. Impact 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 ion exchange constant is used, due to changes in pH, ionic strength, complexation; foliar top dressing 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 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 intake 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 negative consequences, a balanced fertilizer system is used; foliar plant nutrition.

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

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

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

8. Toxication of enzymatic activity.

9. Toxication of the animal world of the soil. As ways to eliminate negative consequences, a balanced fertilizer system is used; increase in soil buffering.

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

11. Loss of humus, change 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 physical and chemical properties of soils. Ways to eliminate - optimization of the fertilizer system, the introduction of ameliorants, organic fertilizers.

13. Deterioration of 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 soil structure.

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

16. The appearance of toxic concentrations of individual elements. To reduce the negative impact, it is necessary to balance the fertilizer system, increase soil buffering, sedimentation and removal of individual elements, and complex formation.

17. Increasing 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 entry of toxicants into plants, and introduce antagonists of toxicants into the soil.

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

Unbalanced use of various fertilizers;

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

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

Incorrect timing of fertilizer application for specific soils and environmental conditions;

The introduction of various toxicants together 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 sphere of production in general, and most importantly in agriculture, which makes it possible to fundamentally solve the problem of food and agricultural raw materials. Without the use of fertilizers, agriculture is now unthinkable.

With proper organization and control of application, mineral fertilizers are not dangerous for the environment, human and animal health. Optimal science-based doses increase plant yield and increase 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 the impact they have on the quality of a particular product, human health and the environment as a whole. Unlike farmers, environmentalists and doctors around the world question the excessive enthusiasm for biochemical innovations that have literally occupied the market today. Fertilizer manufacturers talk side by side about the benefits of their invention, without mentioning the fact 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, worsen the quality of food products, and also significantly affect both human health and the stability of agrocenoses. Ecologists are especially concerned about the fact that biogeochemical cycles are violated in the process of soil pollution, which subsequently leads to an aggravation of the general environmental situation.

List of used literature

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

2. V. F. Val’kov, Yu. A. Shtompel, and V. I. Tyul’panov, Soil Science (Soils of the North Caucasus). – Krasnodar, 2002.

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

The atmosphere always contains a certain amount of impurities coming from natural and anthropogenic sources. More stable zones with a high concentration of pollution appear in places of active human activity. Anthropogenic pollution is characterized by a variety of types and a multitude of sources.

The main causes of environmental pollution with fertilizers, their losses and unproductive use are:

1) imperfection of the technology of transportation, storage, mixing and fertilization;

2) violation of the technology of their application in crop rotation and for individual crops;

3) water and wind erosion of soils;

4) imperfection of chemical, physical and mechanical properties of mineral fertilizers;

5) intensive use of various industrial, municipal and domestic wastes as fertilizers without systematic and careful control of their chemical composition.

From the use of mineral fertilizers, air pollution is insignificant, especially with the transition to the use of granular and liquid fertilizers, but it does occur. After the application of fertilizers, compounds containing mainly nitrogen, phosphorus and potassium are found in the atmosphere.

Significant air pollution also occurs during the production of mineral fertilizers. Thus, dust and gas wastes of potash production include emissions of flue gases from drying departments, the components of which are concentrate dust (KCl), hydrogen chloride, vapors of flotation agents and anti-caking agents (amines). In terms of environmental impact, nitrogen is of paramount importance.

Organic matter, like straw and raw sugar beet leaves, reduced the gaseous loss of ammonia. This can be explained by the content in the compost of CaO, which has alkaline properties, and toxic properties that can suppress the activity of nitrifiers.

Its losses from fertilizers are quite significant. It is assimilated in the field by about 40%, in some cases by 50-70%, immobilized in the soil by 20-30%.

There is an opinion that a more serious source of nitrogen losses than leaching is its volatilization from the soil and fertilizers applied to it in the form of gaseous compounds (15-25%). For example, in European agriculture, 2/3 of nitrogen losses occur in winter and 1/3 in summer.

Phosphorus as a biogenic element is less lost to the environment due to its low mobility in the soil and does not pose such an environmental hazard as nitrogen.

Phosphate losses most often occur during soil erosion. As a result of surface washout of the soil, up to 10 kg of phosphorus is carried away from each hectare.

The atmosphere is self-purifying from pollution as a result of the deposition of solid particles, their washing out of the air by precipitation, dissolution in raindrops and fog, dissolution in the water of the seas, oceans, rivers and other bodies of water, dispersion in space. But, as you know, these processes are very slow.

1.3.3 Impact of mineral fertilizers on aquatic ecosystems

Recently, there has been a rapid increase in the production of mineral fertilizers and the entry of nutrients into land waters, which has created the problem of anthropogenic eutrophication of surface waters as an independent problem. These circumstances, of course, have a natural relationship.

Effluents containing a lot of nitrogen and phosphorus compounds enter water bodies. This is due to the flushing of fertilizers from the surrounding fields into reservoirs. As a result, anthropogenic eutrophication of such water bodies occurs, their unprofitable productivity increases, there is an increased development of phytoplankton of coastal thickets, algae, “water bloom”, etc. Hydrogen sulfide and ammonia accumulate in the deep zone, and anaerobic processes intensify. Redox processes are disturbed and oxygen deficiency occurs. This leads to the death of valuable fish and vegetation, the water becomes unsuitable not only for drinking, but even for swimming. Such a eutrophic water body is losing its economic and biogeocenotic significance. Therefore, the struggle for clean water is one of the most important tasks of the entire complex of the problem of nature protection.

Natural eutrophic systems are well balanced. The artificial introduction of biogenic elements as a result of anthropogenic activity disrupts the normal functioning of the community and creates instability in the ecosystem that is disastrous for organisms. If foreign substances stop entering such water bodies, they can return to their original state.

The optimal growth of aquatic plant organisms and algae is observed at a concentration of phosphorus 0.09-1.8 mg/l and nitrate nitrogen 0.9-3.5 mg/l. Lower concentrations of these elements limit the growth of algae. For 1 kg of phosphorus entering the reservoir, 100 kg of phytoplankton are formed. Water bloom due to algae occurs only when the concentration of phosphorus in the water exceeds 0.01 mg/l.

A significant part of biogenic elements entering rivers and lakes with runoff waters, although in most cases the washout of elements by surface waters is much less than as a result of migration along the soil profile, especially in areas with a leaching regime. Pollution of natural waters with biogenic elements due to fertilizers and their eutrophication occur, first of all, in cases where the agronomic technology of applying fertilizers is violated and a set of agrotechnical measures is not carried out, in general, the culture of agriculture is at a low level.

When using phosphorus mineral fertilizers, the phosphorus removal with liquid runoff increases by about 2 times, while with solid runoff, an increase in phosphorus removal does not occur or even a slight decrease occurs.

With liquid runoff from arable land, 0.0001-0.9 kg of phosphorus per hectare is carried out. From the entire territory occupied by arable land in the world, which is about 1.4 billion hectares, due to the use of mineral fertilizers, in modern conditions, about 230 thousand tons of phosphorus are additionally taken out.

Inorganic phosphorus is found in land waters mainly in the form of orthophosphoric acid derivatives. The forms of existence of phosphorus in water are not indifferent to the development of aquatic vegetation. The most available phosphorus is dissolved phosphates, which are used by them almost completely during the intensive development of plants. Apatite phosphorus, being deposited in bottom sediments, is practically not available to aquatic plants and is poorly used by them.

The migration of potassium along the profile of soils with medium or heavy mechanical composition is significantly hindered due to the absorption by soil colloids and the transition to an exchangeable and non-exchangeable state.

Surface runoff washes away mainly soil potassium. This finds a corresponding expression in the values of the potassium content in natural waters and the absence of a connection between them and the doses of potassium fertilizers.

As for nitrogen fertilizers, mineral fertilizers, the amount of nitrogen in the runoff is 10-25% of its total intake with fertilizers.

The dominant forms of nitrogen in water (excluding molecular nitrogen) are NO 3 ,NH 4 ,NO 2 , soluble organic nitrogen and particulate nitrogen. In lake reservoirs, the concentration can vary from 0 to 4 mg/l.

However, according to a number of researchers, the assessment of the contribution of nitrogen to the pollution of surface and ground waters is apparently overestimated.

Nitrogen fertilizers with a sufficient amount of other nutrients in most cases contribute to intensive vegetative growth of plants, the development of the root system and the absorption of nitrates from the soil. The area of leaves increases and, in connection with this, the transpiration coefficient increases, the water consumption by the plant increases, and soil moisture decreases. All this reduces the possibility of nitrate flushing into the lower horizons of the soil profile and from there into groundwater.

The maximum concentration of nitrogen is observed in surface waters during the flood period. The amount of nitrogen leached from catchment areas during the flood period is largely determined by the accumulation of nitrogen compounds in the snow cover.

It can be noted that the removal of both total nitrogen and its individual forms during the flood period is higher than the reserves of nitrogen in the snow cover. This may be due to erosion of the topsoil and nitrogen leaching with solid runoff.

The application of fertilizers to the soil not only improves plant nutrition, but also changes the conditions for the existence of soil microorganisms, which also need mineral elements.

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

There was a point of view that the long-term use of mineral fertilizers leads to a catastrophic loss of humus and a deterioration in the physical properties of the soil. However, experimental data did not confirm it. So, on the soddy-podzolic soil of the TSCA, Academician D.N. Pryanishnikov laid an experiment with a different fertilizer system. On the plots where mineral fertilizers were used, on average, 36.9 kg of nitrogen, 43.6 kg of P2O5 and 50.1 kg of K2O were applied per 1 ha per year. In the soil fertilized with manure, it was applied annually at the rate of 15.7 t/ha. After 60 years, a microbiological analysis of experimental plots was carried out.

Thus, over 60 years, the humus content in the fallowed soil decreased, but in the fertilized soils, its losses were less than in the unfertilized ones. This can be explained by the fact that the application of mineral fertilizers contributed to the development of autotrophic microflora in the soil (mainly algae), which led to some accumulation of organic substances in the steaming soil, and, consequently, humus. Manure is a direct source of humus formation, the accumulation of which under the action of of this organic fertilizer is quite understandable.

On plots with the same fertilizer, but occupied by agricultural crops, fertilizers acted even more favorably. Harvest 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% humus, which received NPK-1.46, and the manured soil - 1.96%.

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

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

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

With the annual introduction of 144 kg of mineral nitrogen with other minerals (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 occurred with an annual application of 35 tons of manure per 1 ha to the soil (Fig. 71).

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

Experiments conducted by F. V. Turchin showed that the application of nitrogen-containing mineral fertilizers (labeled with 15N) increases the yield of plants not only as a result of a fertilizing effect, but also due to a better use of nitrogen from the soil by plants (Table 27). In the experiment, 420 mg of nitrogen were 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 "breathing" of the soil, that is, the release of CO2 by it. This is the result of accelerated decomposition of soil organic compounds (including humus).

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

The above information allows us to conclude that, in addition to the direct effect on plants, nitrogen mineral fertilizers also have a great 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. Generalization of the results of 3500 experiments with grain crops carried out in the Nonchernozem 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 greater 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 significant 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 shows the generalized data of scientists from the GDR on nitrogen consumption for obtaining 1 quintal of grain on different soils. As can be seen, mineral fertilizers are most economically used on soils containing more humus.

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

Sometimes the application of mineral fertilizers to 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 microorganisms and plants.

The adverse effect of mineral fertilizers was noted on light, infertile sandy and sandy loamy podzolic soils of the Solikamsk agricultural experimental station. One of the analyzes of the variously fertilized soil of this station is given in Table 29.

In this experiment, N90, P90, K120 were introduced into the soil every year, manure - 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 over 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 effects of physiologically acidic mineral fertilizers.

After 14 years, the yields with the application of mineral fertilizers actually dropped to zero as a result of strong soil acidification. The use of liming and manure contributed to the normalization of soil pH and obtaining a crop sufficiently high for the specified conditions. In general, the microflora of the soil and plants reacted to changes in the soil background in approximately 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 effect 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 shortage 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 certain soil-climatic zones.

Let us briefly dwell on the use of microfertilizers. Some of them, such as molybdenum, are part of the enzyme system of nitrogen-fixing microorganisms. For symbiotic nitrogen fixation

boron is also needed, which ensures the formation of a normal vascular system in plants, and, consequently, the successful flow of nitrogen assimilation. Most other trace elements (Cu, Mn, Zn, etc.) in small doses enhance the intensity of microbiological processes in the soil.

As has been shown, organic fertilizers and especially manure have a very favorable effect on the soil microflora. The rate of mineralization of manure in the 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 the manure. Usually manure causes an increase in yield within 2-3 years in contrast to. nitrogen fertilizers that have no aftereffect. Semi-decomposed manure with a narrower C:N ratio exhibits a fertilizing effect from the moment it is applied, since it does not have carbon-rich material that causes vigorous uptake of nitrogen by microorganisms. In rotted manure, a significant part of the nitrogen is converted into humus, which is poorly mineralized. Therefore, manure - sypets as a 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 in certain phases of plant development.

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

Recently, great attention has been paid to the issue of using straw as an organic fertilizer. The introduction of straw could enrich the soil with humus. In addition, the straw contains about 0.5% nitrogen and other elements necessary for plants. During the decomposition of straw, a lot of carbon dioxide is released, which also has a beneficial effect on crops. As early as 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, plowing straw was not recommended. This was justified by the fact that the 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 root nodule bacteria that fix molecular nitrogen; crops that provide themselves with nitrogen with the help of nodule bacteria that fix molecular nitrogen.

The lack of nitrogen after embedding the straw can be compensated 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 adverse 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 topsoil. Here, under aerobic conditions, all substances toxic to plants decompose rather quickly. With a 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 the subtropical and tropical zones, the time gap between straw incorporation and sowing can be minimal even with deep ploughing. Here all the unfavorable moments disappear very quickly.

If these recommendations are followed, the soil is not only enriched with organic matter, but mobilization processes are also 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 conducted in our country, the expediency of using excess straw as an organic fertilizer has been fully confirmed.

Kuban State University

Department of Biology

in the discipline "Soil Ecology"

"The hidden negative effect of fertilizers".

Performed

Afanasyeva L. Yu.

5th year student

(speciality -

"Bioecology")

Checked Bukareva O.V.

Krasnodar, 2010

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

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

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

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

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

Local impact of fertilizers on ecosystems and soils to which they are applied.

Outrageous 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. Effect of mineral fertilizers on soils

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

Increases acidity;

The species composition of soil organisms is changing;

The circulation of substances is disrupted;

The structure that worsens other properties is destroyed.

Optimal doses;

The minimum amount of harmful impurities;

Alternate with organic fertilizers.

2. Effect of mineral fertilizers on atmospheric air and water

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

The use of substances-inhibitors of gaseous losses (nitropyrin).

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

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

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

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

Types of fertilizers	The influence of mineral fertilizers
Types of fertilizers	positive	negative
	Increase the protein content in the grain; improve the baking quality of grain.	At high doses or untimely methods of application - accumulation in the form of nitrates, violent growth to the detriment of stability, increased morbidity, especially 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; help to increase the resistance of plants to diseases.	At high doses, toxicosis of plants is possible. They act mainly through the heavy metals contained in them (cadmium, arsenic, selenium), radioactive elements and fluorine. The main accumulators are parsley, onion, sorrel.
Potash	Similar to phosphorus.	They act mainly through the accumulation of chlorine when making potassium chloride. With an excess of potassium - toxicosis. The main accumulators of potassium are potatoes, grapes, buckwheat, greenhouse vegetables.

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

Types of fertilizers	Main Impacts
Nitrogen - nitrate forms	Nitrates (maximum concentration limit for water 10 mg/l, for food - 500 mg/day per person) are reduced in the body to nitrites, which cause 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, loss of eyelashes, rupture of the alveoli. In animal husbandry: beriberi, reduced productivity, accumulation of urea in milk, increased morbidity, reduced fertility.
Phosphoric - superphosphate	They act mainly through fluorine. Its excess in drinking water (more than 2 mg / l) causes damage to the enamel of teeth in humans, loss of elasticity of blood vessels. At a content of more than 8 mg / l - osteochondrosis phenomena.
Chlorine-containing fertilizers - potassium chloride - ammonium chloride	Consumption of water with a chlorine content of more than 50 mg/l causes poisoning (toxicosis) in humans and animals.

Of the individual nutrients, potash and phosphorus fertilizers have a positive effect on the formation of the generative organs of wintering grape eyes and on increasing the frost resistance of plants, 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 of plants leads to a decrease in their frost resistance.
Therefore, the regime of soil nutrition is of great importance for increasing the frost resistance of a grape plant. The frost resistance 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, plants assimilate poorly and, as a result, do not lay down the necessary reserves of plastic substances for the winter. The hardening of such plants in autumn is unsatisfactory. Therefore, fertilization of vineyards should be considered as a necessary agricultural technique that improves their frost resistance.
Other agrotechnical measures are also of great importance in increasing the frost resistance of vine bushes: loading bushes, green operations, tying shoots, etc. Overloading bushes with a crop on a low agrotechnical background weakens the growth of shoots, worsens their maturation, which also reduces their frost resistance. In insufficiently loaded bushes, growth can be excessively strong and prolonged, as a result of which a general delay in vegetation can also lead to undermaturation of the vine and, consequently, to a decrease in plant resistance to low temperatures. Thus, low temperatures especially damage those plants that, for one reason or another, were insufficiently prepared for winter.
Studies on the influence of the mineral nutrition regime on the frost resistance of a grape plant, carried out in the conditions of Armenia on the Voskehat variety, showed that bushes that were fertilized with a mixture of NPK survived better during winter frosts than bushes that received only nitrogen or incomplete fertilizer (Table 10 ).