Influence 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.
Under 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 increases the intensity of microbiological processes, resulting in a conjugated increase in the transformation of organic and mineral substances.
A characteristic indicator of the activation of microbial activity under the influence of fertilizers is the 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 best action mineral fertilizers against the background of high cultivation of the soil.
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 changes natural principles interactions of plants, animals and soil, adapting technologies for the most effective results in 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.
In our time, the cultivation of vegetables and fruits - berry crops It is hard to imagine without mineral fertilizers. After all, they all provide positive influence on plants without which it is difficult to imagine their normal growth. Even ardent opponents of mineral fertilizers admit that they have an optimal effect on seedlings and do not harm the soil.
Of course, if mineral fertilizers are poured onto a small area in large big bags, there can be no talk about their benefits, but if you follow all the rules and technologies, then everything will definitely work out. In this article, you will learn about the effect of certain mineral compounds on plants, because each of them will be used in different cases.
Let's start with the effect of nitrogen fertilizers on plants. First, nitrogen is one of the main elements that affect the growth of a seedling. They are advised to be used by introducing directly into the soil during spring plowing in the form of urea (carbamide) or ammonia acid. Note that nitrogen fertilizers in in large numbers transported in special big bags.
When should nitrogen fertilizers be applied?
They are used when there is a lack of nitrogen in plants. Determining the lack of nitrogen is very simple. Plant leaves turn yellow or pale green.
The main advantages of nitrogen fertilizers:
1) They can be operated on different soils;
2) They fertilizers create conditions for the rapid growth of the plant;
3) They fertilizers improve fruit quality.
Now we will talk about the effects of potassium compounds on seedlings. Potassium is an element that affects yield, drought tolerance and low temperature tolerance. Finding out that a plant is deficient in potassium is as easy as finding out that a plant is deficient in nitrogen. A sign that the plant lacks potassium is white borders along the edge of the leaf, low elasticity of the leaf. When using potash fertilizers, plants quickly revive and grow.
When using potassium salts, you need to remember the rules and technologies for their use and avoid abuse, because mineral fertilizers should be applied only when necessary. Also, do not forget that the soil needs to be allowed to rest.
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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-aggregate state, 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 adequate content 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 suggests 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, conversely, clumping, 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 conditions, what
subsequently negatively affects the development of the root system of agricultural plants. At the same time, the requirements different plants to the density of the soil are not the same and depend on the type of soil, mechanical composition, 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 effect 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 root system powerful in volume and mass 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 more intensive decomposition. plant residues, due to which there is an increase in the water resistance of the soil. 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 calculated from the results of not only wet screening, but also dry screening.
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
Of the individual nutrients, potash and phosphate 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 more early ripening 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.
Consequently, great importance to increase the frost resistance of a grape plant, it has a soil nutrition regime. The frost resistance of plants increases with the availability of all necessary elements supply, 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, the fertilization of vineyards should be considered as a necessary agricultural technique improving their frost resistance.
In increasing frost resistance grape bushes Other agrotechnical measures are also of great importance: loading bushes, green operations, tying shoots, etc. Overloading bushes with a crop on a low agrotechnical background weakens the growth of shoots, impairs 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. In this way, low temperatures especially those plants are damaged that, for one reason or another, turned out to be 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 the bushes, which were fertilized with a mixture of NPK, during winter frosts survived better than bushes that received only nitrogen or incomplete fertilizer (Table 10).