About the negative impact of mineral fertilizers. Influence of mineral fertilizers on the development of harmful organisms Negative effect of fertilizers on the soil

INFLUENCE OF SOIL TREATMENT AND MINERAL FERTILIZERS ON AGROPHYSICAL PROPERTIES OF TYPICAL CHERNOZEM

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

Annotation. As a result of the research, an ambiguous effect of the method of basic tillage for winter wheat and corn and mineral fertilizers on the indicators of the agrophysical state of typical chernozem has been established. Optimal indicators of density, structural state were obtained during moldboard plowing. It was revealed that the use of mineral fertilizers worsens the structural state of aggregation, but contributes to an increase in the water resistance of soil units during moldboard plowing in relation to zero and surface tillage.

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

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

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

Thus, the purpose of this work was to study the effect of tillage, mineral fertilizers and the previous crop on the agrophysical properties of typical chernozem.

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

In the experiment, the following methods of basic tillage were studied: 1) moldboard plowing by 20-22 cm; 2) surface treatment - 10-12 cm; 3) zero tillage - direct sowing with John Deere seeder. Mineral fertilizers: 1) without fertilizers; 2) for winter wheat N2^52^2; for corn K14eR104K104.

Sampling was carried out in the third decade of May, in a layer of 0-20 cm. The density of the soil was determined by the drilling method according to N. A. Kachinsky. To study the structural-aggregate state, undisturbed soil samples weighing more than 1 kg were selected. To isolate structural units and aggregates, the method of N. I. Savvinov was used to determine the structural-aggregate composition of the soil - dry and wet sifting.

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

subsequently negatively affects the development of the root system of agricultural plants. At the same time, the requirements of different plants for soil density are not the same and depend on the type of soil, mechanical composition, and cultivated crop. So, the optimal soil density for grain crops is 1.051.30 g/cm3, for corn - 1.00-1.25 g/cm3.

The conducted studies have shown that under the influence of various soil treatments, a change in density occurs (Figure 1). Regardless of the cultivated crop, the highest soil density was in no-till variants, slightly lower in surface tillage. The optimal soil density is noted in the variants with moldboard plowing. Mineral fertilizers with all methods of basic cultivation contribute to an increase in soil density.

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

Moldboard Surface Cooling

processing processing

Basic tillage method

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

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

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

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

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

The content of water stable aggregates (>0.25 mm) is a criterion for assessing and predicting the stability of the addition of the arable layer in time, its resistance to the degradation of physical properties under the influence of natural and anthropogenic factors. Optimal content of water-stable aggregates >0.25 mm in the topsoil different types soils is 40-70(80)%. When studying the influence of the main tillage methods (table 2), it was found that with zero tillage the amount of water-resistant aggregates was higher than with surface tillage and moldboard plowing.

Table 2 - Change in water resistance of macro-

This is directly related to the weighted average diameter of water resistant aggregates, since no-till increases the size of soil units that are water resistant. The structural coefficient of waterproof aggregates decreases in the series: surface tillage ^ zero tillage ^ moldboard plowing. According to the estimated

On an indicative scale, the criterion of water resistance of aggregates at zero tillage is assessed as very good, and at surface tillage and moldboard plowing - as good.

Studying the influence of the cultivated crop, it was found that in the soil under corn, the weighted average diameter, the coefficient of structure, as well as the sum of water-stable aggregates were higher than under winter wheat, which is associated with the formation of a powerful root system in terms of volume and weight under grain crops, which contributed to the formation greater water resistance under corn. The water resistance criterion behaved differently and was higher in the soil under wheat than under corn.

When applying fertilizers on the variant with moldboard plowing, the structure coefficient, the weighted average diameter and the sum of water-resistant aggregates increased. Since moldboard plowing goes with the turnover of the layer and is much deeper than surface and, especially, zero tillage, then the incorporation of mineral fertilizers occurs deeper, therefore, at a depth, the humidity is higher, which contributes to a more intensive decomposition of plant residues, due to which there is an increase soil water resistance. In the variants with the use of surface and zero tillage, all studied indicators of soil water resistance decreased when mineral fertilizers were applied. The criterion of water resistance of soil aggregates in all variants of the experiment increased, which is due to the fact that this indicator is calculated based on the results of not only wet sifting, but also dry sieving.

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

Organic and mineral fertilizers have a huge impact on the soil. In fact, such an agrotechnical function as soil fertilization is a more intense imitation of complex natural processes occurring in an ecosystem over long periods.

Man is changing the natural principles of interaction between plants, animals and soil, adapting technologies to the most effective results when growing crops.

The effect of fertilizers on the soil can be different - both positive and negative. In order not to harm the soil, plants and beneficial microorganisms, it is necessary to comply with agrotechnical and environmental standards developed for various agricultural types of fertilizers.

The most useful for the soil are natural fertilizers. First of all, it is freshwater silt. It can be applied in its pure form or diluted with compost, or mixed with other types of fertilizers.

Acidophilic crops prefer acidic soil. How can you change the pH of the soil to the acidic side? For this purpose, such a type of natural fertilizer as needles is well suited. The introduction of needles into the ground can give a good effect for acidophilic plants, but will negatively affect other species that require a neutral or alkaline soil environment to grow.

Many fruit trees (primarily apples and pears) need iron during the ripening period. So the processing fruit trees ferrous sulfate will help to provide them with iron, which will favorably affect the yield, size and bright color of the fruit.

Nitrogen fertilizers should be applied to the soil with care. The fact is that as a result of the accumulation of nitrate salts (nitrates) in the soil, many agricultural crops accumulate nitrates in themselves and become poisonous to humans and animals. This is especially true for melon crops.

The use of iodine fertilizers for top dressing outside the root system gives a good effect on vegetable crops and fruit and berry plants (adds up to 40% yield).

Some plants prefer alkaline soil. In addition, a situation often arises when plants and soil are significantly polluted by vehicle exhausts and other industrial waste.

This leads to the accumulation of heavy metals in the soil, which, with a high degree of probability, leads to diseases in humans and animals. Lime or ash can be used to neutralize heavy metals and change the pH of the soil to alkaline. alkali binds heavy metals turning them into salts.

There are other types of fertilizers that allow you to change the structure, acidity, fertility, salinity and other soil indicators. The main thing is that when using fertilizers, agrotechnical and environmental standards are not violated.

Fertilizers replenish the reserves of nutrients in the soil in an accessible form and supply them to plants. At the same time, they provide big influence soil properties and thus affect the yield also indirectly. By increasing the yield of plants and the mass of roots, fertilizers enhance the positive effect of plants on the soil, contribute to an increase in humus in it, and improve its chemical, water-air and biological properties. Organic fertilizers (manure, composts, green manure) have a great direct positive effect on all these soil properties.
Acid mineral fertilizers, if they are systematically applied without organic fertilizers(and on acidic soils without lime) can have a negative effect on soil properties (Table 123). Long-term use of them on acidic non-lime soils leads to a decrease in soil saturation with bases, increases the content of toxic aluminum compounds and toxic microorganisms, worsens the water-physical properties of the soil, increases bulk density (density), reduces soil porosity, its aeration and water permeability. As a result of the deterioration of soil properties, the increase in yields from fertilizers is reduced, and the “hidden negative effect” of acid fertilizers on the crop is manifested.

Bad influence acid mineral fertilizers on the properties of acidic soils is associated not only with the free acidity of fertilizers, but also with the effect of their bases on the absorbing complex of the soil. By displacing exchangeable hydrogen and aluminum, they convert the exchangeable acidity of the soil into active acidity and, at the same time, strongly acidify the soil solution, dispersing the colloids that hold the structure together and reducing its strength. Therefore, when applying large doses of mineral fertilizers, not only the acidity of the fertilizers themselves, but also the exchangeable acidity of the soil should be taken into account.
Lime neutralizes the acidity of the soil, improves its agrochemical properties and eliminates the negative effect of acidic mineral fertilizers. Even small doses of lime (from 0.5 to 2 t/ha) increase the saturation of the soil with bases, reduce acidity and sharply reduce the amount of toxic aluminum, which in acidic podzolic soils has an extremely strong negative effect on plant growth and yield.
In long-term experiments with the use of acidic mineral fertilizers on chernozems, a slight increase in soil acidity and a decrease in the amount of exchangeable bases are also noted (Table 124), which can be eliminated by introducing small amounts of lime.

Organic fertilizers have a great and always positive effect on all soils. Under the influence of organic fertilizers - manure, peat composts, green manure - the humus content increases, the saturation of the soil with bases, including calcium, improves the biological and physical properties of the soil (porosity, moisture capacity, water permeability), and in acidic soils, acidity, content toxic aluminum compounds and toxic microorganisms. However, a significant increase in the content of humus in the soil and an improvement in its physical properties are noted only with the systematic introduction of large doses of organic fertilizers. Their single application to acidic soils together with lime improves the qualitative group composition of humus, but does not lead to a noticeable increase in its percentage in the soil.
Similarly, peat introduced into the soil without prior composting does not have a noticeable positive effect on soil properties. Its influence on the soil increases dramatically if it is previously composted with manure, slurry, feces or mineral fertilizers, especially alkaline ones, since peat itself decomposes very slowly and in acidic soils forms many highly dispersed fulvic acids that support the acidic reaction of the environment.
The joint application of organic fertilizers with mineral fertilizers has a great positive effect on the soil. At the same time, the number and activity of nitrifying bacteria and bacteria that fix atmospheric nitrogen, oligonitrophils, free-living nitrogen fixers, etc., increase especially sharply. podzolizing the soil.

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 need mineral elements.

With favorable climatic conditions the number of microorganisms and their activity after the introduction of fertilizers into the soil increase significantly. The decomposition 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 is more easily decomposed and used by microorganisms. The application 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 acid side as a result of the introduction of physiologically acidic salts: actinomycetes do not tolerate acidification well, and the reproduction of many fungi accelerates 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 crop and root residues left.

The introduction of mineral and organic fertilizers into the soil enhances the intensity of microbiological processes, as a result of which the transformation of organic and mineral substances increases concurrently.

A characteristic indicator of the activation of microbial activity under the influence of fertilizers is the increased "respiration" of the soil, i.e., the release of CO 2 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.

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 microorganisms and plants 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 effects of physiologically acidic mineral fertilizers.

The influence of mineral fertilizers 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, in the north, there is a stronger shortage 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.

Plants need to grow and develop nutrients. Some of them are green spaces obtained directly from the soil, and some are extracted from mineral fertilizers. Artificial soil mineralization allows you to get big crops, but is it safe? So far, modern breeders have not been able to get an unequivocal answer to this question, but research in this area continues.

Benefit or harm?

Many mineral fertilizers are considered harmful to human health, and the plants that have absorbed them are almost poisonous. In fact, this statement is nothing more than an established stereotype based on the lack of agrotechnical knowledge.

Important! The difference between organic and mineral fertilizers is not at all in the benefits or harms, but in the speed of assimilation.

Organic fertilizers are absorbed slowly. In order for a plant to get the substances it needs from organic matter, it must decompose. The microflora of the soil is involved in this process, which significantly slows it down. Weeks and even months pass from the moment natural dressings are introduced into the soil and before they are used by plants.

Mineral fertilizers enter the soil already in finished form. Plants get access to them immediately after application. This has a positive effect on the growth rate and allows you to harvest a good harvest even where normal conditions like this is impossible. Unfortunately, this is where the positive aspects of using mineral supplements in most cases end.

Improper use of them can lead to:

• the disappearance from the soil of bacteria involved in the natural process of decomposition;
• pollution of groundwater and the atmosphere (the pollution involves individual components of mineral fertilizers washed out of the soil before they are absorbed by plants);
• changes in soil acidity;
• accumulation in the soil of compounds atypical for the natural environment;
• leaching of useful cations from the soil;
• decrease in the amount of humus in the soil;
• soil compaction;
• erosion.

A moderate amount of minerals in the soil is good for plants, but many vegetable growers use more fertilizer than they need. Such irrational use leads to saturation with minerals not only of the root and stem, but also of that part of the plant that is intended for human consumption.

Important! Compounds atypical for a plant affect health, provoke the development of diseases.

Pesticides and pesticides

In order for the plant to grow and develop quickly, fertilizers applied to the soil are not enough. You can get a good harvest only by protecting it from pests. For this purpose, farmers use various pesticides and pesticides. The need for their use arises in the case of:

• lack of natural means to combat the invasion of insects (fields are treated against locusts, moths, etc.);
• infection of plants with dangerous fungi, viruses and bacteria.

Pesticides and pesticides are used to control weeds, rodents and other pests. Chemicals are selected in such a way that they affect only specific rodents, a variety of weeds or pests. Cultivated plants treated together with weeds, negative impact chemical substances do not experience. Processing does not affect their appearance in any way, but pesticides and pesticides are deposited in the soil and, together with minerals, first penetrate the plant itself, and from there into the person who used it.

Unfortunately, chemical treatment fields in most cases is the only way to get good harvest. Significant sown areas leave no alternative ways to solve the problem. The only way out is to track the quantity and quality of pesticides used. For this purpose, special services have been created.

Negative influence

The greatest harm to the environment and humans is caused by various aerosols and gases sprayed over large areas. Improper use of pesticides and fertilizers is fraught with serious consequences. In this case, the negative impact can manifest itself years and decades later.

Impact on a person

When using fertilizers and pesticides, you must follow the instructions. Failure to comply with the rules for applying top dressings and chemicals can lead to poisoning not only of the vegetable itself, but also of a person. So, if an unreasonably high dose of nitrogen got into the soil, with a minimum content of phosphorus, potassium and molybdenum in it, nitrates dangerous for the human body begin to accumulate in plants.

Vegetables and fruits rich in nitrates affect the gastrointestinal tract, increase the risk of developing cancer. Under the influence of a large number of chemicals and fertilizers, the biochemical composition of food is modified. Vitamins and nutrients almost completely disappear from them, they are replaced by dangerous nitrites.

A person who regularly consumes vegetables and fruits treated with chemicals and grown exclusively on mineral fertilizers often complains of headaches, heart palpitations, muscle numbness, visual and hearing impairments. Such vegetables and fruits cause the greatest harm to pregnant women and children. An excess of toxins in the body of a newborn can have unpredictable consequences.

Soil impact

As mentioned above, mineral fertilizers and chemicals negatively affect, first of all, the soil. Improper use of them leads to the depletion of the soil layer, changes in the structure of the soil, erosion. Thus, nitrogen entering the groundwater provokes the growth of vegetation. Organic matter accumulates in the water, the amount of oxygen decreases, swamping begins, due to which the landscape in this area can irreversibly change. Soils saturated with minerals and poisons can dry out, fertile chernozems cease to produce high yields, and nothing but weeds grows on less fertile soils.

Environmental impact

Not only fertilizers have a negative impact, but also the process of their production. Lands on which new types of fertilizers are tested are rapidly leaching, losing their natural fertile layer. Transportation and storage of chemicals are no less dangerous. People in contact with them are required to use gloves and respirators. Fertilizers must be stored in a place specially designated for this, where children and pets will not have access. Failure to follow simple precautions can provoke a real environmental disaster. So, some pesticides can cause massive fall of foliage from trees and shrubs, wilting of herbaceous vegetation.

In order to use mineral fertilizers without consequences for the environment, soils and health, farmers must adhere to the following rules:

• organic fertilizers are used wherever possible (modern organics are not a complete, but good enough replacement for mineral fertilizers);
• before using fertilizers, read the instructions (when choosing them, special attention is paid to the composition of the soil, the quality of the fertilizers themselves, the variety and type of crop grown);
• top dressing is combined with soil acidification measures (lime or wood ash is added along with minerals);
• use only those fertilizers that contain the minimum amount of harmful additives;
• the timing and dose of minerals are not violated (if nitrogen fertilization should be done in early May, then using this fertilizer in early June may be wrong and even dangerous).

Important! To minimize the negative effect of non-natural supplements, farmers alternate them with organics, which helps to reduce nitrate levels and reduce the risk of intoxication.

It will not be possible to completely abandon pesticides, but under conditions of a small farming their use can be kept to a minimum.

Conclusion

The use of mineral fertilizers and pesticides simplifies the work of the farmer, allowing you to get a significant amount of the crop with minimal cost. The cost of top dressing is low, while their introduction increases soil fertility several times. Despite the existing risk of harm to the soil and human health, farmers using mineral supplements can grow cultivated plants previously unwilling to take root.

Soil mineralization increases the resistance of plants to pests and diseases, allows you to store the resulting product longer than usual and improve its presentation. Fertilizers can be easily applied even without special agrotechnical education. Using them has both pros and cons, as described in more detail above.