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

INFLUENCE OF SOIL TREATMENT AND MINERAL FERTILIZER 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, the ambiguous influence of the method of the main tillage for winter wheat and corn and mineral fertilizers on the indicators of the agrophysical state of typical chernozem. Optimum indicators of density, structural condition 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 treatments.

Key words: structural and aggregate state, soil density, water resistance, soil cultivation, mineral fertilizers.

Fertile soil, along with sufficient nutrient content, must have favorable physical conditions for the growth and development of crops. It has been established that the structure of the soil 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 when caring for crops and contribute to the disturbance of a very valuable granular structure, as a result of which it can be sprayed or, on the contrary, lump, which is permissible up to certain limits in the soil.

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

The studies were carried out in 2009-2010. in LLC "AgroSil" (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 hydrolyzable nitrogen (according to Cornfield) - 13.6 mg / 100 g. Cultivated crops: winter wheat variety "Augusta" and corn hybrid PR-2986.

In the experiment, the following methods of basic soil cultivation were studied: 1) moldboard plowing by 20-22 cm; 2) surface treatment - 10-12 cm; 3) no till - direct seeding with John Deere planter. 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. Soil density was determined using the drilling method according to N.A.Kachinsky. To study the structural and 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 the 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 to soil density are not the same and depend on the type of soil, mechanical composition, and cultivated culture. So, the optimal soil density for grain crops is 1.051.30 g / cm3, for corn - 1.00-1.25 g / cm3.

Studies have shown that under the influence of various soil treatments, there is a change in density (Figure 1). Regardless of the cultivated crop, the highest soil density was in the no-till options, slightly lower in the shallow tillage. Optimum soil density is noted in the options with moldboard plowing. Mineral fertilizers with all methods of basic processing contribute to an increase in soil density.

The obtained experimental data confirm the ambiguity of the influence of the methods of the main tillage on the indicators of its structural state (table 1). So, on variants with no 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.

Mouldboard Surface Coolant

processing processing

Method of basic tillage

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

Nevertheless, the structural coefficient, which characterizes 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. In the cultivation of winter wheat, the number of aggregates of the agronomically valuable range and the coefficient of structure were higher by an average of 20% than in the soil under corn. This is due biological characteristics the structure of the root system of these crops.

Considering the factor of fertilization, I would like to note that the use of fertilizers led to a noticeable decrease in both the agronomically valuable structure and the coefficient of structure, which is quite natural, since in the first and second years after application there is a deterioration in the structure of aggregates and agrophysical properties of the soil - the density of packing 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 - Influence of the method of soil cultivation and mineral fertilizers on the indicators of structural

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

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

Table 2 - Change in water resistance of macro-

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

on a rough scale, the criterion of water resistance of aggregates at zero tillage is assessed as very good, and as good at surface tillage and moldboard plowing.

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

When applying fertilizers on the option with moldboard plowing, the structural coefficient, the weighted average diameter and the amount of waterproof aggregates increased. Since moldboard plowing goes with a seam turnover and is much deeper than surface and even more zero tillage, then the incorporation of mineral fertilizers occurs deeper, therefore, at depth, the humidity is higher, which contributes to more intensive decomposition of plant residues, due to which an increase water resistance of the soil. On the variants with the use of surface and no-till, all the studied indicators of soil water resistance decreased with the use of mineral fertilizers. The criterion of the water resistance of soil aggregates in all variants of the experiment increased, which is due to the fact that this indicator is calculated according to the results of not only wet sieving, but also dry sieving.

The ambiguous influence of the studied factors on the indicators of the agrophysical state of typical chernozem was established. So, the most optimal indicators of density, structural state were revealed during moldboard plowing, somewhat worse with surface and zero tillage. Indicators of water resistance decreased in the following order: zero tillage ^ surface treatment ^ dump plowing. The use of mineral fertilizers worsens the structural and aggregate state, but contributes to an increase in the water resistance of soil units during moldboard plowing in relation to zero and surface treatments. In the cultivation of 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 intensely expressed imitation of complex natural processes occurring in the ecosystem over long periods.

Man changes the natural principles of the interaction of plants, animals and soil, adapting technologies for 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.

Natural fertilizers are most useful for the soil. First of all, it is freshwater silt. It can be applied neat 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, a type of natural fertilizer such as needles is well suited. Adding needles to the ground can have a good effect on acidophilic plants, but will negatively affect other species that require a neutral or alkaline soil environment to grow.

Many fruit trees (primarily apple and pear) require iron during the ripening period. Thus, the treatment of fruit trees with iron vitriol will help to provide them with iron, which will have a beneficial effect on 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 toxic to humans and animals. This is especially true for melons and gourds.

The use of iodine fertilizers for feeding outside the root system has 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 there is significant pollution of plants and soil by vehicle exhaust 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 of humans and animals. Lime or ash can be used to neutralize heavy metals and change the pH of the soil to alkaline. Lye binds heavy metalsturning them into salts.

There are other types of fertilizers that can 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 plants with them. At the same time, they have a great influence on the properties of the soil 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, improve its chemical, water-air and biological properties. Organic fertilizers (manure, composts, green fertilizers) have a great direct positive effect on all these soil properties.
Acidic mineral fertilizers, if they are systematically applied without organic fertilizers (and on acidic soils without lime), can have a negative effect on the properties of the soil (Table 123). Long-term use of them on acidic uncoated soils leads to a decrease in soil saturation with bases, increases the content of toxic aluminum compounds and toxic microorganisms, impairs the water-physical properties of the soil, increases the bulk density (density), reduces the porosity of the soil, its aeration and water permeability. As a result of the deterioration of soil properties, the increase in yields from fertilizers decreases, and the "latent negative effect" of acid fertilizers on the harvest is manifested.

Negative influence acid mineral fertilizers on the properties of acidic soils is associated not only with the free acidity of fertilizers, but also with the action of their bases on the absorbing complex of the soil. 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 should be taken into account, but also the exchangeable acidity of the soil.
Lime neutralizes soil acidity, 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 using acidic mineral fertilizers on chernozems, a slight increase in soil acidity and a decrease in the amount of exchangeable bases (Table 124) are also noted, which can be eliminated by the introduction of small amounts of lime.

Organic fertilizers have a large and always positive effect on all soils. Under the influence of organic fertilizers - manure, peat composts, green manure - the humus content increases, the soil saturation with bases, including calcium, improves, the biological and physical properties of the soil (porosity, moisture capacity, water permeability) improve, and in soils with an acid reaction, acidity, toxic aluminum compounds and toxic microorganisms. However, a significant increase in the humus content in the soil and an improvement in its physical properties are observed only with the systematic application of large doses of organic fertilizers. A single introduction of them into 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.
Likewise, peat applied to the soil without composting does not have a noticeable positive effect on soil properties. Its effect on the soil increases sharply if it is pre-composted with manure, slurry, feces or mineral fertilizers, especially alkaline ones, since peat itself decomposes very slowly and in acidic soils it forms many highly dispersed fulvic acids that maintain an acidic reaction of the environment.
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 fixing atmospheric nitrogen - oligonitrophils, free-living nitrogen fixers, and others - increase especially sharply. In acidic podzolic soils, the number of microorganisms on Aristovskaya's medium decreases, which, in her opinion, produce a large amount of strong acids, 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 require mineral elements.

With favorable climatic conditions the number of microorganisms and their activity after the introduction of fertilizers into the soil increases significantly. Decomposition of humus intensifies, 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 addition 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, as a result of which the transformation of organic and mineral substances increases.

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 C0 2 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-buffered 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.

For the growth and development of plants, nutrients are needed. 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 yields, but is it safe? Modern breeders have not yet been able to get an unambiguous 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 matter and mineral fertilizers is not at all in the benefit or harm, but in the rate of assimilation.

Organic fertilizers are absorbed slowly. For a plant to be able to obtain the substances it needs from organic matter, it must decompose. The soil microflora is involved in this process, which significantly slows it down. Weeks and even months pass from the moment of introducing natural dressings into the soil until the plants start using them.

Mineral fertilizers are supplied to the soil ready-made. Plants gain access to them immediately after application. This has a positive effect on the growth rate and allows a good harvest even where the normal conditions this is impossible. Unfortunately, this is where the positive aspects of using mineral dressings end in most cases.

Their incorrect use can lead to:

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

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

Important! Compounds that are atypical for a plant affect health and provoke the development of diseases.

Pesticides and toxic chemicals

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 toxic chemicals. The need for their application arises in the case of:

• lack of natural remedies to combat insect infestations (fields are cultivated against locusts, moths, etc.);
• infection of plants with dangerous fungi, viruses and bacteria.

Pesticides and toxic chemicals are used to combat weeds, rodents and other pests. Chemicals are selected so that they only target specific rodents, weeds or pests. Crop plants treated with weeds, negative impact chemical substances do not experience. Processing does not affect their appearance in any way, but pesticides and toxic chemicals are deposited in the soil and, together with minerals, first penetrate into 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 acreage leaves no alternative solutions to the problem. The only way out of the situation 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. At the same time, the negative impact can manifest itself after years and decades.

Impact on a person

When using fertilizers and pesticides, you must follow the instructions. Failure to comply with the rules for the introduction of 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 gets into the soil, with a minimum content of phosphorus, potassium and molybdenum in it, nitrates dangerous for the human body begin to accumulate in the plants.

Nitrate-rich vegetables and fruits affect the gastrointestinal tract and increase the risk of developing cancer. Under the influence of a large number of chemicals and fertilizers, the biochemical composition of food is altered. 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 headache, heart palpitations, muscle numbness, visual and hearing impairments. Such fruits and vegetables cause the greatest harm to pregnant women and children. An excess of toxins in a newborn's body can have unpredictable consequences.

Impact on soil

As mentioned above, mineral fertilizers and chemicals negatively affect, first of all, the soil. Improper use of them leads to depletion of the soil layer, changes in soil structure, erosion. So, nitrogen that gets into groundwater provokes the growth of vegetation. Organic matter accumulates in the water, the amount of oxygen decreases, waterlogging 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 give high yields, on less fertile soils, nothing but weeds grows.

Impact on the environment

Not only fertilizers have a negative impact, but also the process of their production. Lands on which new types of fertilizers are being tested are quickly leached out, 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. You need to store fertilizers in a specially designated place, where there will be no access to children and pets. Failure to follow simple precautions can provoke a real environmental disaster. So, some pesticides can cause massive foliage from trees and shrubs, wilting of herbaceous vegetation.

To use mineral fertilizers without impact on the environment, soil and health, farmers must adhere to the following rules:

• organic fertilizers are used wherever possible (modern organic matter is not a complete, but quite good substitute for mineral fertilizers);
• before using fertilizers, read the instructions (when choosing them, special attention is paid to the composition of the soils, the quality of the fertilizers themselves, the variety and type of crop grown);
• feeding is combined with measures for acidifying the soil (lime or wood ash is added along with minerals);
• use only those fertilizers that contain a 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 using unnatural dressings, farmers alternate them with organic substances, which helps to reduce the level of nitrates and reduce the risk of intoxication.

It will not be possible to completely abandon pesticides, but in conditions of small farms you can keep their use to a minimum.

Conclusion

The use of mineral fertilizers and pesticides simplifies the farmer's work, allowing a significant amount of harvest to be obtained at minimal costs... The cost of fertilizing is low, while their introduction increases the fertility of the soil several times. Despite the existing risk of harm to the soil and human health, farmers using mineral fertilizing can grow crops that previously did not want to take root.

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