Summary: Hidden negative effect of fertilizers. The effect of mineral fertilizers on product quality and human health The effect of fertilizers on soil children's encyclopedia
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 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). By influence on environment 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, 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, there is an increase in the phosphorus removal with liquid runoff 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.
Municipal budgetary educational institution "Secondary school named after Dmitry Batiev" with. Gam Ust - Vymsky District Komi Republic
Work completed: Isakova Irina, student
Head: , teacher of biology and chemistry
Introduction………………………………………………..………………………………………3
I. Main part………………………………………………………………….….….…..4
Classification of mineral fertilizers…………………………………………..….....4
II. Practical part….…………………………………………….……………..............6
2.1 Growing plants at different concentrations of minerals… ..….6
Conclusion…………………………………….…………………………………………....9
List of literature used………………………………………….…………….10
Introduction
Relevance of the problem
Plants absorb minerals from the soil along with water. In nature, these substances then return to the soil in one form or another after the death of the plant or its parts (for example, after leaf fall). Thus, there is a circulation of minerals. However, such a return does not occur, since minerals are carried away from the fields during harvesting. To avoid soil depletion, people make various fertilizers in the fields, gardens and orchards. Fertilizers improve soil nutrition of plants, improve soil properties. As a result, the yield increases.
The aim of the work is: to study the effects of mineral fertilizers on the growth and development of plants.
- To study the classification of mineral fertilizers. Experimentally determine the degree of influence of potash and phosphorus fertilizers on the growth and development of plants. Design a booklet "Recommendations for gardeners"
Practical significance:
Vegetables play a very important role in human nutrition. A fairly large number of gardeners grow vegetables on their plots. Mine garden plot helps to save some, and also makes it possible to grow organic products. Therefore, the results of the study can be used when working in the country and the garden.
Research methods: study and analysis of literature; conducting experiments; comparison.
Literature review. When writing the main part of the project, sites were used, the site "Secret of the cottage", the site "Wikipedia" and others. The practical part is based on the work, "Simple Experiments in Botany".
1 Main body
Classification of mineral fertilizers
Fertilizers are substances used to improve plant nutrition, soil properties, and increase yields. Their effect is due to the fact that these substances provide plants with one or more deficient chemical components necessary for their normal growth and development. Fertilizers are divided into mineral and organic.
Mineral fertilizers - extracted from the bowels or industrially obtained chemical compounds, contain the main nutrients (nitrogen, phosphorus, potassium) and trace elements important for life. They are made in special factories, they contain nutrients in the form of mineral salts. Mineral fertilizers are divided into simple (one-component) and complex. Simple mineral fertilizers contain only one of the main nutrients. These include nitrogen, phosphorus, potash fertilizers and microfertilizers. Complex fertilizers contain at least two main nutrients. In turn, complex mineral fertilizers are divided into complex, complex-mixed and mixed.
Nitrogen fertilizers.
Nitrogen fertilizers enhance the growth of roots, bulbs and tubers. At fruit trees and berry bushes, nitrogen fertilizers not only increase the yield, but also improve the quality of the fruit. Nitrogen fertilizers are applied in early spring in any form. The deadline for applying nitrogen fertilizers is mid-July. This is due to the fact that fertilizers stimulate the growth of the aerial part, the leaf apparatus. If they are introduced in the second half of summer, then the plant will not have time to acquire the necessary winter hardiness, and will freeze in winter. Excess nitrogen fertilizer worsens survival.
Phosphorus fertilizers.
Phosphate fertilizers stimulate the development of the root system of plants. Phosphorus enhances the ability of cells to retain water and thereby increases the resistance of plants against drought and low temperatures. With sufficient nutrition, phosphorus accelerates the transition of plants from the vegetative phase to fruiting. Phosphorus has a positive effect on the quality of fruits - it contributes to an increase in sugar, fats, and proteins in them. Phosphorus fertilizers can be applied every 3-4 years.
potassium fertilizers.
Potash fertilizers are responsible for the strength of shoots and trunks, therefore they are especially relevant for shrubs and trees. Potassium has a positive effect on the intensity of photosynthesis. If there is enough potassium in plants, then their resistance to various diseases increases. Potassium also promotes the development of mechanical elements of vascular bundles and bast fibers. With a lack of potassium, development is delayed. Potash fertilizers are applied under plants starting from the second half of summer.
2. Practical part
2.1 Growing plants at different concentrations of minerals
To complete the practical part, you will need: bean sprouts, in the phase of the first true leaf; three pots filled with sand; pipette; three solutions of nutrient salts containing potassium, nitrogen and phosphorus.
The amount of nutrients in fertilizers was calculated. Solutions of optimal concentrations were prepared. These solutions were used to feed the plants and monitor the growth and development of plants.
Preparation of nutrient solutions.
*Water for preparing the solution is hot
2 bean sprouts were planted in pots with moistened sand. A week later, they left one in each bank, best plant. On the same day, solutions of mineral salts prepared in advance were added to the sand.
During the experiment, supported optimum temperature air and normal sand. Three weeks later, the plants were compared with each other.
Experience results.
Description of plants | plant height | number of leaves |
|
Pot number 1 "No salt" | The leaves are pale, dull green, starting to turn yellow. The tips and edges of the leaves turn brown, small rusty spots appear on the leaf blade. The sheet size is slightly smaller than other samples. The stem is thin, inclined, slightly branched. | ||
Pot number 2 "Less salt" | The leaves are pale green. Leaves are medium to large. There are no visible damage. The stem is thick and branched. | ||
Pot #3 "More Salts" | The leaves are bright green and large. The plant looks healthy. The stem is thick and branched. |
Based on the experimental results, the following conclusions can be drawn:
- For normal growth and development of plants, minerals are necessary (development of beans in pots No. 2 and No. 3). They can be absorbed only in dissolved form. The full development of plants occurs with the use of complex fertilizers (nitrogen, phosphorus, potash). The amount of fertilizer applied must be strictly dosed.
As a result of the experience and the study of literature, some rules for the use of fertilizers have been drawn up:
Organic fertilizers cannot fully satisfy the plants with nutrients, therefore mineral fertilizers are also added. In order not to harm plants and soil, it is necessary to have an elementary understanding of the consumption of nutrients and mineral fertilizers by plants. When using mineral fertilizers, the following must be remembered:
- do not exceed the recommended doses and apply only in those phases of plant growth and development, when necessary; avoid getting fertilizer on the leaves; conduct liquid top dressing after watering, otherwise you can burn the roots; stop any fertilizing four to ten weeks before harvest to avoid the accumulation of nitrates.
Conclusion
The use of mineral fertilizers is one of the main methods of intensive farming. With the help of fertilizers, you can dramatically increase the yields of any crop. Mineral salts are of great importance for the growth and development of plants. Plants look healthy.
Thanks to experience, it became clear that regular fertilization of plants with fertilizers should become a common procedure, since many violations in the development of plants are caused precisely by improper care associated with a lack of nutrition, which happened in our case.
There are many important things for plants. One of them is the soil, it also needs to be selected correctly for each specific plant. Apply fertilizer according to appearance and physiological state of plants.
Fertilizers replenish the reserves of nutrients in the soil in an accessible form and supply them to plants. At the same time, they have a great influence on the properties of the soil and thus also affect the yield 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 impact 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.
The negative effect of acidic 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 agro Chemical 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 humus content in the soil and improvement physical properties it is 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 increase especially sharply - oligonitrophils, free-living nitrogen fixers, etc. In acidic podzolic soils, the number of microorganisms on the Aristovskaya medium decreases, which, in her opinion, produce a large amount of strong podzolizing the soil.
The use of mineral fertilizers (even in high doses) does not always lead to the predicted increase in yield.
Numerous studies indicate that the weather conditions of the growing season have such a strong influence on the development of plants that extremely adverse weather conditions actually neutralize the effect of increasing yields even at high doses of application. nutrients(Strapenyants et al., 1980; Fedoseev, 1985). The coefficients of use of nutrients from mineral fertilizers can differ sharply depending on the weather conditions of the growing season, decreasing for all crops in years with insufficient moisture (Yurkin et al., 1978; Derzhavin, 1992). In this regard, any new methods to improve the efficiency of mineral fertilizers in areas of unsustainable agriculture deserve attention.
One of the ways to increase the efficiency of the use of nutrients from fertilizers and soil, strengthen plant immunity to adverse environmental factors and improve the quality of the products obtained is the use of humic preparations in the cultivation of crops.
Over the past 20 years, there has been a significant increase in interest in humic substances used in agriculture. The topic of humic fertilizers is not new either for researchers or for agricultural practitioners. Since the 50s of the last century, the effect of humic preparations on the growth, development, and yield of various crops has been studied. Currently, due to a sharp rise in the price of mineral fertilizers, humic substances are widely used to increase the efficiency of the use of nutrients from the soil and fertilizers, increase plant immunity to adverse environmental factors and improve the quality of the crop of the products obtained.
Diverse raw materials for the production of humic preparations. These can be brown and dark coals, peat, lake and river sapropel, vermicompost, leonardite, as well as various organic fertilizers and waste.
The main method for obtaining humates today is the technology of high-temperature alkaline hydrolysis of raw materials, which results in the release of surface-active high-molecular organic substances of various masses, characterized by a certain spatial structure and physico-chemical properties. The preparative form of humic fertilizers can be a powder, paste or liquid with different specific gravity and concentration of the active substance.
The main difference for various humic preparations is the form of the active component of humic and fulvic acids and (or) their salts - in water-soluble, digestible or indigestible forms. The higher the content of organic acids in a humic preparation, the more valuable it is both for individual use and especially for obtaining complex fertilizers with humates.
There are various ways of using humic preparations in crop production: processing seed, foliar top dressing, introduction of aqueous solutions into the soil.
Humates can be used both separately and in combination with plant protection products, growth regulators, macro- and microelements. The range of their use in crop production is extremely wide and includes almost all agricultural crops produced both in large agricultural enterprises and in personal subsidiary plots. Recently, their use in various ornamental crops has grown significantly.
Humic substances have a complex effect that improves the condition of the soil and the system of interaction "soil - plants":
- increase the mobility of assimilable phosphorus in soil and soil solutions, inhibit immobilization of assimilable phosphorus and retrogradation of phosphorus;
- radically improve the balance of phosphorus in soils and phosphorus nutrition of plants, which is expressed in an increase in the proportion of organophosphorus compounds responsible for the transfer and transformation of energy, the synthesis of nucleic acids;
- improve soil structure, their gas permeability, water permeability of heavy soils;
- maintain the organo-mineral balance of soils, preventing their salinization, acidification and other negative processes leading to a decrease or loss of fertility;
- shorten the vegetative period by improving protein metabolism, concentrated delivery of nutrients to the fruit parts of plants, saturating them with high-energy compounds (sugars, nucleic acids, and other organic compounds), and also suppress the accumulation of nitrates in the green part of plants;
- enhance the development of the root system of the plant due to good nutrition and accelerated cell division.
Particularly important are beneficial features humic components to maintain the organo-mineral balance of soils with intensive technologies. In the article by Paul Fixen "The concept of increasing the productivity of crops and the efficiency of using nutrients by plants" (Fixen, 2010), a link is given to a systematic analysis of methods for assessing the efficiency of using nutrients by plants. As one of the significant factors affecting the efficiency of the use of nutrients, the intensity of crop cultivation technologies and the associated changes in the structure and composition of the soil, in particular, the immobilization of nutrients and the mineralization of organic matter, are indicated. Humic components in combination with key macronutrients, primarily phosphorus, maintain soil fertility under intensive technologies.
In the work of Ivanova S.E., Loginova I.V., Tyndall T. “Phosphorus: mechanisms of losses from the soil and ways to reduce them” (Ivanova et al., 2011), the chemical fixation of phosphorus in soils is noted as one of the main factors of a low degree the use of phosphorus by plants (at the level of 5 - 25% of the amount of phosphorus introduced in the 1st year). Increasing the degree of phosphorus use by plants in the year of application has a pronounced environmental effect - reducing the ingress of phosphorus with surface and underground runoff into water bodies. The combination of the organic component in the form of humic substances with the mineral in fertilizers prevents the chemical fixation of phosphorus into poorly soluble calcium, magnesium, iron and aluminum phosphates and retains phosphorus in a form available to plants.
In our opinion, the use of humic preparations in the composition of mineral macrofertilizers is very promising.
Currently, there are several ways to introduce humates into dry mineral fertilizers:
- surface treatment of granulated industrial fertilizers, which is widely used in the preparation of mechanical fertilizer mixtures;
- mechanical introduction of humates into powder with subsequent granulation in small-scale production of mineral fertilizers.
- introduction of humates into the melt during large-scale production of mineral fertilizers (industrial production).
The use of humic preparations for the production of liquid mineral fertilizers used for foliar treatment of crops has become very widespread in Russia and abroad.
The purpose of this publication is to show the comparative effectiveness of humated and conventional granular mineral fertilizers on grain crops (winter and spring wheat, barley) and spring rapeseed in various soil and climatic zones of Russia.
Sodium humate Sakhalin was chosen as a humic preparation to obtain guaranteed high results in terms of agrochemical efficiency with the following indicators ( tab. 1).
The production of Sakhalin humate is based on the use of brown coal from the Solntsevo deposit on Sakhalin, which have a very high concentration of humic acids in digestible form (more than 80%). Alkaline extract from brown coals of this deposit is almost completely soluble in water, non-hygroscopic and non-caking powder of dark brown color. Microelements and zeolites also pass into the composition of the product, which contribute to the accumulation of nutrients and regulate the metabolic process.
In addition to the indicated indicators of sodium humate "Sakhalin", an important factor his choice as a humic additive was the production of concentrated forms of humic preparations in industrial quantities, high agrochemical indicators of individual application, the content of humic substances mainly in water-soluble form and the presence of a liquid form of humate for uniform distribution in the granule at industrial production, as well as state registration as an agrochemical.
In 2004, Ammofos JSC in Cherepovets produced an experimental batch of a new type of fertilizer - azophoska (nitroammophoska) grade 13:19:19, with the addition of Sakhalin sodium humate (alkaline extract from leonardite) into the pulp according to technology, developed at OAO NIUIF. The quality indicators of humated ammophoska 13:19:19 are given in tab. 2.
The main task during industrial testing was to substantiate the optimal method for introducing the Sakhalin humate additive while maintaining the water-soluble form of humates in the product. It is known that humic compounds in acidic environments (at pH<6) переходят в формы водорастворимых гуматов (H-гуматы) с потерей их эффективности.
The introduction of powdered humate "Sakhalinsky" into the recycle in the production of complex fertilizers ensured that the humate did not come into contact with an acidic medium in the liquid phase and its undesirable chemical transformations. This was confirmed by the subsequent analysis of finished fertilizers with humates. The introduction of humate actually at the final stage of the technological process determined the preservation of the achieved productivity of the technological system, the absence of return flows and additional emissions. There was also no deterioration in physicochemical complex fertilizers (caking, granule strength, dustiness) in the presence of a humic component. The hardware design of the humate injection unit also did not present any difficulties.
In 2004, CJSC "Set-Orel Invest" (Oryol region) conducted a production experiment with the introduction of humated ammophosphate for barley. The increase in barley yield on an area of 4532 hectares from the use of humated fertilizer compared to the standard ammophos grade 13:19:19 was 0.33 t/ha (11%), the protein content in the grain increased from 11 to 12.6% ( tab. 3), which gave the farm an additional profit of 924 rubles/ha.
In 2004, field experiments were conducted at the SFUE OPH "Orlovskoye" All-Russian Research Institute of Legumes and Cereals (Oryol Region) to study the effect of humated and conventional ammophoska (13:19:19) on the yield and quality of spring and winter wheat.
Experiment scheme:
- Control (no fertilizer)
N26 P38 K38 kg a.i./ha
N26 P38 K38 kg a.i./ha humated
N39 P57 K57 kg a.i./ha
N39 P57 K57 kg a.i./ha humated.
In the experiment with spring wheat (variety Smena), the maximum yield of 2.78 t/ha was also observed when an increased dose of humated fertilizer was applied. In the same variant, the highest content of protein and gluten in the grain was observed. As in the experiment with winter wheat, the application of humated fertilizer statistically significantly increased the yield and the content of protein and gluten in the grain compared to the application of the same dose of standard mineral fertilizer. The latter works not only as an individual component, but also improves the absorption of phosphorus and potassium by plants, reduces the loss of nitrogen in the nitrogen cycle of nutrition, and generally improves the exchange between soil, soil solutions and plants.
A significant improvement in the quality of the crop and winter and spring wheat indicates an increase in the efficiency of mineral nutrition of the production part of the plant.
According to the results of the action, the humate additive can be compared with the influence of microcomponents (boron, zinc, cobalt, copper, manganese, etc.). With a relatively small content (from tenths to 1%), humate additives and microelements provide almost the same increase in yield and quality of agricultural products. The work (Aristarkhov, 2010) studied the effect of microelements on the yield and quality of grain of cereals and legumes and showed an increase in protein and gluten on the example of winter wheat with the main application on various types of soil. The directed influence of microelements and humates on the productive part of crops is comparable in terms of the results obtained.
High agrochemical production results with minimal refinement of the instrumentation scheme for large-scale production of complex fertilizers, obtained from the use of humated ammophoska (13:19:19) with Sakhalin sodium humate, made it possible to expand the range of humated grades of complex fertilizers with the inclusion of nitrate-containing grades.
In 2010, OJSC Mineralnye Udobreniya (Rossosh, Voronezh Region) produced a batch of humated azophoska 16:16:16 (N:P 2 O 5:K 2 O) containing humate (alkaline extract from leonardite) - not less than 0.3% and moisture - not more than 0.7%.
Azofoska with humates was a light gray granular organomineral fertilizer, differing from the standard one only in the presence of humic substances in it, which gave a barely noticeable light gray tint to the new fertilizer. Azofoska with humates was recommended as an organo-mineral fertilizer for the main and “before sowing” application to the soil and for root dressings for all crops where conventional azofoska can be used.
In 2010 and 2011 On the experimental field of the State Scientific Institution Moscow Research Institute of Agriculture "Nemchinovka", studies were carried out with humated azophos produced by JSC "Mineral Fertilizers" in comparison with the standard one, as well as with potash fertilizers (potassium chloride) containing humic acids (KaliGum), in comparison with the traditional potash fertilizer KCl.
Field experiments were carried out according to the generally accepted methodology (Dospekhov, 1985) on the experimental field of the Moscow Research Institute of Agriculture "Nemchinovka".
A distinctive feature of the soils of the experimental plot is a high content of phosphorus (about 150-250 mg/kg), and an average content of potassium (80-120 mg/kg). This led to the abandonment of the main application of phosphate fertilizers. The soil is soddy-podzolic medium loamy. Agrochemical characteristics of the soil before laying the experiment: the content of organic matter - 3.7%, pHsol. -5.2, NH 4 - - traces, NO 3 - - 8 mg / kg, P 2 O 5 and K 2 O (according to Kirsanov) - 156 and 88 mg/kg, respectively, CaO - 1589 mg/kg, MgO - 474 mg/kg.
In the experiment with azofoska and rapeseed, the size of the experimental plot was 56 m 2 (14m x 4m), the repetition was four times. Pre-sowing tillage after the main fertilization - with a cultivator and immediately before sowing - with RBC (rotary harrow-cultivator). Sowing - with an Amazon seeder in optimal agrotechnical terms, seeding depth of 4-5 cm - for wheat and 1-3 cm - for rapeseed. Seeding rates: wheat - 200 kg/ha, rapeseed - 8 kg/ha.
In the experiment, spring wheat variety MIS and spring rapeseed variety Podmoskovny were used. The MIS variety is a highly productive mid-season variety that allows you to consistently obtain grain suitable for the production of pasta. The variety is resistant to lodging; much weaker than the standard is affected by brown rust, powdery mildew and hard smut.
Spring rapeseed Podmoskovny - mid-season, vegetation period 98 days. Ecologically plastic, characterized by uniform flowering and maturation, resistance to lodging 4.5-4.8 points. The low content of glucosinolates in the seeds allows the use of cake and meal in the diets of animals and poultry at higher rates.
The wheat crop was harvested in the phase of full grain ripeness. Rape was cut for green fodder in the flowering phase. Experiments for spring wheat and rapeseed were laid out according to the same scheme.
The analysis of soil and plants was carried out according to standard and generally accepted methods in agrochemistry.
Scheme of experiments with azofoska:
Background (50 kg a.i. N/ha for top dressing)
Background + azophoska main application 30 kg a.i. NPK/ha
Background + azophoska with humate main application 30 kg a.i. NPK/ha
Background + azophoska main application 60 kg a.i. NPK/ha
Background + azophoska with humate main application 60 kg a.i. NPK/ha
Background + azophoska main application 90 kg a.i. NPK/ha
Background + azophoska with humate main application 90 kg a.i. NPK/ha
During the years of research, the weather conditions differed significantly from the long-term average for the Non-Chernozem zone. In 2010, May and June were favorable for the development of agricultural crops, and generative organs were laid in plants with the prospect of a future grain yield of about 7 t/ha for spring wheat (as in 2009) and 3 t/ha for rapeseed. However, as in the entire Central region of the Russian Federation, a long drought was observed in the Moscow region from early July until the wheat harvest in early August. The average daily temperatures during this period were exceeded by 7 ° C, and daytime temperatures were above 35 ° C for a long time. Separate short-term precipitation fell in the form of heavy rains and water flowed down with surface runoff and evaporated, only partially absorbed into the soil. The saturation of the soil with moisture during short periods of rain did not exceed the penetration depth of 2-4 cm. In 2011, in the first ten days of May, after sowing and during plant germination, precipitation fell almost 4 times less (4 mm) than the weighted average long-term norm (15 mm).
The average daily air temperature during this period (13.9 o C) was significantly higher than the long-term average daily temperature (10.6 o C). The amount of precipitation and air temperature in the 2nd and 3rd decades of May did not differ significantly from the amount of average precipitation and average daily temperatures.
In June, the precipitation was much less than the average long-term norm, the air temperature exceeded the average daily by 2-4 o C.
July was hot and dry. In total, during the growing season, precipitation was 60 mm less than the norm, and the average daily air temperature was about 2 o C higher than the long-term average. Unfavorable weather conditions in 2010 and 2011 could not but affect the state of crops. The drought coincided with the grain filling phase of wheat, which ultimately led to a significant reduction in yield.
Prolonged air and soil drought in 2010 did not give the expected effect from increasing doses of azophoska. This has been shown in both wheat and rapeseed.
Moisture deficiency turned out to be the main obstacle in the implementation of the soil fertility, while the wheat yield was generally two times lower than in the similar experiment in 2009 (Garmash et al., 2011). Yield increases when applying 200, 400 and 600 kg/ha of azofoska (physical weight) were almost the same ( tab. 5).
The low yield of wheat is mainly due to the frailty of the grain. The mass of 1000 grains in all variants of the experiment was 27–28 grams. Data on the structure of the yield on the variants did not differ significantly. In the mass of the sheaf, the grain was about 30% (under normal weather conditions, this figure is up to 50%). The tillering coefficient is 1.1-1.2. The mass of grain in an ear was 0.7-0.8 grams.
At the same time, in the variants of the experiment with humated azofoska, a significant yield increase was obtained with an increase in fertilizer doses. This is due, first of all, to the better general condition of plants and the development of a more powerful root system when using humates against the background of the general stress of crops from long and prolonged drought.
A significant effect from the use of humated azofoska was manifested at the initial stage of development of rapeseed plants. After sowing rapeseed seeds, as a result of a short rainstorm followed by high air temperatures, a dense crust formed on the soil surface. Therefore, seedlings on the variants with the introduction of conventional azophoska were uneven and very sparse compared to the variants with humated azophoska, which led to significant differences in the yield of green mass ( tab. 6).
In the experiment with potash fertilizers, the area of the experimental plot was 225 m 2 (15 m x 15 m), the experiment was repeated four times, the location of the plots was randomized. The area of the experiment is 3600 m 2 . The experiment was carried out in the link of crop rotation winter cereals - spring cereals - busy fallow. The predecessor of spring wheat is winter triticale.
Fertilizers were applied manually at the rate of: nitrogen - 60, potassium - 120 kg of a.i. per ha. Ammonium nitrate was used as nitrogen fertilizers, and potassium chloride and the new KaliGum fertilizer were used as potash fertilizers. In the experiment, spring wheat variety Zlata, recommended for cultivation in the Central region, was grown. The variety is early maturing with a productivity potential of up to 6.5 t/ha. Resistant to lodging, much weaker than the standard variety is affected by leaf rust and powdery mildew, at the level of the standard variety - by septoria. Before sowing, the seeds were treated with the Vincit disinfectant in the norms recommended by the manufacturer. In the tillering phase, wheat crops were fertilized with ammonium nitrate at the rate of 30 kg of a.i. per 1 ha.
Scheme of experiments with potash fertilizers:
- Control (no fertilizer).
N60 basic + N30 top dressing
N60 basic + N30 top dressing + K 120 (KCl)
N60 basic + N30 top dressing + K 120 (KaliGum)
Thus, field experiments have reliably proven the agrochemical effectiveness of complex fertilizers with humate additives, determined by the increase in yield and protein content in grain crops. To ensure these results, it is necessary to correctly select a humic preparation with a high proportion of water-soluble humates, its form and place of introduction into the technological process at the final stages. This makes it possible to achieve a relatively low content of humates (0.2 - 0.5% wt.) in humated fertilizers and to ensure a uniform distribution of humates over the granule. At the same time, an important factor is the preservation of a high proportion of the water-soluble form of humates in humated fertilizers.
Complex fertilizers with humates increase the resistance of agricultural crops to adverse weather and climatic conditions, in particular, to drought and deterioration of soil structure. They can be recommended as effective agrochemicals in areas of risky farming, as well as when using intensive farming methods with several crops per year to maintain high soil fertility, in particular, in expanding zones with a water deficit and arid zones. The high agrochemical efficiency of the humated ammophoska (13:19:19) is determined by the complex action of the mineral and organic parts with an increase in the action of nutrients, primarily phosphorus nutrition of plants, an improvement in the metabolism between soil and plants, and an increase in plant stress resistance.
Levin Boris Vladimirovich – candidate of technical sciences, deputy general. Director, Director for Technical Policy of PhosAgro-Cherepovets JSC; e-mail:[email protected] .
Ozerov Sergey Alexandrovich - Head of Market Analysis and Sales Planning Department of PhosAgro-Cherepovets JSC; e-mail:[email protected] .
Garmash Grigory Alexandrovich - Head of the Laboratory of Analytical Research of the Federal State Budgetary Scientific Institution "Moscow Research Institute of Agriculture" Nemchinovka ", Candidate of Biological Sciences; e-mail:[email protected] .
Garmash Nina Yuryevna - Scientific Secretary of the Moscow Research Institute of Agriculture "Nemchinovka", Doctor of Biological Sciences; e-mail:[email protected] .
Latina Natalya Valerievna - General Director of Biomir 2000 LLC, Production Director of the Sakhalin Humat Group of Companies; e-mail:[email protected] .
Literature
Paul I. Fixsen The concept of increasing the productivity of agricultural crops and the efficiency of the use of nutrients by plants // Plant Nutrition: Bulletin of the International Institute of Plant Nutrition, 2010, No. 1. - With. 2-7.
Ivanova S.E., Loginova I.V., Tundell T. Phosphorus: mechanisms of losses from the soil and ways to reduce them // Plant Nutrition: Bulletin of the International Institute of Plant Nutrition, 2011, No. 2. - With. 9-12.
Aristarkhov A.N. et al. The effect of microfertilizers on productivity, protein harvest and product quality of grain and leguminous crops // Agrochemistry, 2010, No. 2. - With. 36-49.
Strapenyants R.A., Novikov A.I., Strebkov I.M., Shapiro L.Z., Kirikoy Ya.T. Modeling of the regularities of the action of mineral fertilizers on the crop. Vestnik s.-kh. Nauki, 1980, No. 12. - p. 34-43.
Fedoseev A.P. Weather and fertilizer efficiency. Leningrad: Gidrometizdat, 1985. - 144 p.
Yurkin S.N., Pimenov E.A., Makarov N.B. Influence of soil and climatic conditions and fertilizers on the consumption of the main nutrients in the wheat crop // Agrochemistry, 1978, No. 8. - P. 150-158.
Derzhavin L.M. The use of mineral fertilizers in intensive agriculture. M.: Kolos, 1992. - 271 p.
Garmash N.Yu., Garmash G.A., Berestov A.V., Morozova G.B. Trace elements in intensive technologies for the production of grain crops // Agrochemical Bulletin, 2011, No. 5. - P. 14-16.
Various biogenic elements, getting into the soil with fertilizers, undergo significant transformations. At the same time, they have a significant impact on soil fertility.
And the properties of the soil, in turn, can have both positive and negative effects on the applied fertilizers. Negative influence. This relationship between fertilizers and soil is very complex and requires deep and detailed research. Various sources of their losses are also associated with the conversion of fertilizers in the soil. This problem is one of the main tasks of agrochemical science. R. Kundler et al. (1970) generally show the following possible transformations of various chemical compounds and the associated loss of nutrients through leaching, volatilization in gaseous form and fixation in the soil.
It is quite clear that these are only some indicators of the conversion of various forms of fertilizers and nutrients in the soil, they still do not cover the many ways in which various mineral fertilizers are converted, depending on the type and properties of the soil.
Since the soil is an important part of the biosphere, it is primarily subjected to a complex complex effect of applied fertilizers, which can have the following effect on the soil: cause acidification or alkalization of the environment; improve or worsen the agrochemical and physical properties of the soil; promote the exchange absorption of ions or displace them into the soil solution; promote or prevent the chemical absorption of cations (biogenic and toxic elements); promote mineralization or synthesis of soil humus; enhance or weaken the effect of other soil nutrients or fertilizers; mobilize or immobilize soil nutrients; cause antagonism or synergism of nutrients and, therefore, significantly affect their absorption and metabolism in plants.
In the soil, there can be complex direct or indirect interactions between biogenic toxic elements, macro- and microelements, and this has a significant impact on soil properties, plant growth, their productivity and crop quality.
Thus, the systematic use of physiologically acidic mineral fertilizers on acidic soddy-podzolic soils increases their acidity and accelerates the leaching of calcium and magnesium from the arable layer and, consequently, increases the degree of unsaturation with bases, reducing soil fertility. Therefore, on such unsaturated soils, the use of physiologically acidic fertilizers must be combined with soil liming and neutralization of mineral fertilizers.
Twenty years of fertilizer application in Bavaria on silty, poorly drained soil, combined with grass liming, resulted in an increase in pH from 4.0 to 6.7. In the absorbed soil complex, exchangeable aluminum was replaced by calcium, which led to a significant improvement in soil properties. Losses of calcium as a result of leaching amounted to 60-95% (0.8-3.8 c/ha per year). Calculations showed that the annual need for calcium was 1.8-4 q/ha. In these experiments, the yield of agricultural plants correlated well with the degree of saturation of the soil with bases. The authors concluded that a soil pH >5.5 and a high degree of base saturation (V = 100%) are required to obtain a high yield; at the same time, exchangeable aluminum is removed from the zone of the greatest location of the root system of plants.
In France, the great importance of calcium and magnesium in increasing soil fertility and improving their properties has been revealed. It has been established that leaching leads to depletion of calcium and magnesium reserves.
in the soil. On average, the annual loss of calcium is 300 kg/ha (200 kg on acidic soil and 600 kg on carbonate), and magnesium - 30 kg/ha (on sandy soils they reached 100 kg/ha). In addition, some crop rotations (legumes, industrial, etc.) take significant amounts of calcium and magnesium out of the soil, so the crops following them often show symptoms of deficiency of these elements. It should also not be forgotten that calcium and magnesium play the role of physicochemical ameliorants, having a beneficial effect on the physical and chemical properties of the soil, as well as on its microbiological activity. This indirectly affects the conditions of mineral nutrition of plants with other macro- and microelements. To maintain soil fertility, it is necessary to restore the levels of calcium and magnesium lost as a result of leaching and removal from the soil by agricultural crops; for this, 300-350 kg of CaO and 50-60 kg of MgO per 1 ha should be applied annually.
The task is not only to replenish the losses of these elements due to leaching and removal by agricultural crops, but also to restore soil fertility. In this case, the application rates of calcium and magnesium depend on the initial pH value, the content of MgO in the soil and the fixing capacity of the soil, i.e., primarily on the content of physical clay and organic matter in it. It has been calculated that in order to increase soil pH by one unit, it is necessary to apply lime from 1.5 to 5 t/ha, depending on the content of physical clay (<10% - >30%), To increase the magnesium content in the topsoil by 0.05%, 200 kg MgO/ha must be applied.
It is very important to establish the correct doses of lime in the specific conditions of its use. This question is not as simple as it is often made out to be. Usually, the doses of lime are set depending on the degree of acidity of the soil and its saturation with bases, as well as the type of soil. These issues require further, deeper study in each specific case. An important issue is the frequency of lime application, the fractional application in crop rotation, the combination of liming with phosphorite and the application of other fertilizers. The need for advanced liming as a condition for increasing the efficiency of mineral fertilizers on acidic soils of the taiga-forest and forest-steppe zones has been established. Liming significantly affects the mobility of macro- and microelements of the applied fertilizers and the soil itself. And this affects the productivity of agricultural plants, the quality of food and feed, and, consequently, the health of humans and animals.
M. R. Sheriff (1979) believes that the possible overliming of soils can be judged by two levels: 1) when the productivity of pastures and animals does not increase with the additional application of lime (the author calls this the maximum economic level) and 2) when liming disturbs the balance of nutrients substances in the soil, and this adversely affects plant productivity and animal health. The first level in most soils is observed at a pH of about 6.2. On peat soils the maximum economic level is noted at pH 5.5. Some pastures on light volcanic soils do not show any signs of lime responsiveness at their natural pH of 5.6.
It is necessary to strictly take into account the requirements of cultivated crops. So, the tea bush prefers acidic red soils and yellow earth-podzolic soils, liming inhibits this culture. The introduction of lime adversely affects flax, potatoes (details) and other plants. Legumes, which are inhibited on acidic soils, respond best to lime.
The problem of plant productivity and animal health (second level) most often occurs at pH = 7 or more. In addition, soils vary in speed and degree of responsiveness to lime. For example, according to M.R. Sheriff (1979), to change the pH from 5 to 6 for light soils, it takes about 5 t/ha, and for heavy clay soil 2 times large quantity. It is also important to take into account the content of calcium carbonate in the lime material, as well as the looseness of the rock, the fineness of its grinding, etc. From an agrochemical point of view, it is very important to take into account the mobilization and immobilization of macro- and microelements in the soil under the action of liming. It has been established that lime mobilizes molybdenum, which in excess can adversely affect plant growth and animal health, but at the same time there are symptoms of copper deficiency in plants and livestock.
The use of fertilizers can not only mobilize individual soil nutrients, but also bind them, turning them into a form inaccessible to plants. Studies conducted in our country and abroad show that the one-sided use of high doses of phosphate fertilizers often significantly reduces the content of mobile zinc in the soil, causing zinc starvation of plants, which adversely affects the quantity and quality of the crop. Therefore, the use of high doses of phosphorus fertilizers often necessitates the application of zinc fertilizers. Moreover, the introduction of one phosphorus or zinc fertilizer may not give an effect, and their combined use will lead to a significant positive interaction between them.
There are many examples that testify to the positive and negative interaction of macro- and microelements. At the All-Union Scientific Research Institute of Agricultural Radiology, the effect of mineral fertilizers and soil liming with dolomite on the intake of strontium (90 Sr) radionuclide into plants was studied. The content of 90 Sr in the yield of rye, wheat and potatoes under the influence of complete mineral fertilizer decreased by 1.5-2 times compared with unfertilized soil. The lowest content of 90 Sr in the wheat crop was in the variants with high doses of phosphate and potash fertilizers (N 100 P 240 K 240), and in potato tubers, when high doses of potash fertilizers were applied (N 100 P 80 K 240). The introduction of dolomite reduced the accumulation of 90 Sr in the wheat crop by 3-3.2 times. The introduction of full fertilizer N 100 P 80 K 80 against the background of liming with dolomite reduced the accumulation of radiostrontium in grain and wheat straw by 4.4-5 times, and at a dose of N 100 P 240 K 240 - 8 times compared with the content without liming.
F. A. Tikhomirov (1980) points to four factors that affect the size of the removal of radionuclides from soils by crops: biogeochemical properties of technogenic radionuclides, soil properties, biological characteristics of plants, and agrometeorological conditions. For example, from the arable layer of typical soils of the European part of the USSR, as a result of migration processes, 1-5% of the 90 Sr contained in it and up to 1% of 137 Cs are removed; on light soils, the rate of removal of radionuclides from the upper horizons is significantly higher than on heavy soils. The best provision of plants with nutrients and their optimal ratio reduce the flow of radionuclides into plants. Crops with deep root systems (alfalfa) accumulate less radionuclides than those with shallow root systems (ryegrass).
On the basis of experimental data in the laboratory of radioecology of Moscow State University, a system of agro-measures was scientifically substantiated, the implementation of which significantly reduces the flow of radionuclides (strontium, cesium, etc.) into crop production. These activities include: dilution of radionuclides entering the soil in the form of practically weightless impurities with their chemical analogues (calcium, potassium, etc.); reducing the degree of availability of radionuclides in the soil by introducing substances that convert them into less accessible forms (organic matter, phosphates, carbonates, clay minerals); incorporation of the contaminated soil layer into the subsurface horizon beyond the zone of distribution of root systems (to a depth of 50-70 cm); selection of crops and varieties accumulating minimal amounts of radionuclides; placement of industrial crops on contaminated soils, use of these soils for seed plots.
These measures can also be used to reduce the contamination of agricultural products and non-radioactive toxic substances.
Studies by E. V. Yudintseva et al. (1980) also found that calcareous materials reduce the accumulation of 90 Sr from soddy-podzolic sandy soil in barley grain about 3 times. The introduction of increased doses of phosphorus against the background of blast-furnace slags reduced the content of 90 Sr in barley straw by 5-7 times, in grain - by 4 times.
Under the influence of lime materials, the content of cesium (137 Cs) in the barley yield decreased by 2.3-2.5 times compared with the control. With the joint introduction of high doses of potash fertilizers and blast-furnace slags, the content of 137 Cs in straw and grain decreased by 5-7 times compared with the control. The effect of lime and slag on reducing the accumulation of radionuclides in plants is more pronounced on soddy-podzolic soil than on gray forest soil.
Research by US scientists found that when using Ca(OH) 2 for liming, the toxicity of cadmium decreased as a result of the binding of its ions, while the use of CaCO 3 for liming was ineffective.
In Australia, the effect of manganese dioxide (MnO 2 ) on the absorption of lead, cobalt, copper, zinc and nickel by clover plants was studied. It was found that when manganese dioxide was added to the soil, the absorption of lead and cobalt and, to a lesser extent, nickel decreased more strongly; MnO 2 had little effect on the absorption of copper and zinc.
Studies have also been conducted in the USA on the effects of varying levels of lead and cadmium in soil on maize uptake of calcium, magnesium, potassium, and phosphorus, as well as plant dry weight.
It can be seen from the table that cadmium had a negative effect on the intake of all elements in 24-day-old corn plants, and lead slowed down the intake of magnesium, potassium and phosphorus. Cadmium also had a negative effect on the intake of all elements in 31-day-old corn plants, and lead had a positive effect on the concentration of calcium and potassium and a negative effect on the content of magnesium.
These questions are of important theoretical and practical value, especially for agriculture in industrialized areas, where the accumulation of a number of microelements, including heavy metals, is increasing. At the same time, there is a need for a deeper study of the mechanism of interaction of various elements on their entry into the plant, on the formation of the crop and product quality.
The University of Illinois (USA) also studied the effect of the interaction of lead and cadmium on their uptake by corn plants.
Plants show a definite tendency to increase cadmium uptake in the presence of lead; soil cadmium, on the contrary, reduced lead uptake in the presence of cadmium. Both metals at the tested concentrations suppressed the vegetative growth of corn.
Of interest are studies carried out in Germany on the effect of chromium, nickel, copper, zinc, cadmium, mercury, and lead on the absorption of phosphorus and potassium by spring barley and the movement of these nutrients in the plant. Labeled atoms 32 P and 42 K were used in the studies. Heavy metals were added to the nutrient solution at a concentration of 10 -6 to 10 -4 mol/l. A significant intake of heavy metals into the plant with an increase in their concentration in the nutrient solution was established. All metals exerted (to varying degrees) an inhibitory effect both on the entry of phosphorus and potassium into plants and on their movement in the plant. The inhibitory effect on the intake of potassium was manifested to a greater extent than that of phosphorus. In addition, the movement of both nutrients into the stems was suppressed more strongly than the entry into the roots. The comparative effect of metals on the plant occurs in the following descending order: mercury → lead → copper → cobalt → chromium → nickel → zinc. This order corresponds to the electrochemical series of voltages of the elements. If the effect of mercury in solution was clearly manifested already at a concentration of 4∙10 -7 mol / l (= 0.08 mg / l), then the effect of zinc was only at a concentration above 10 -4 mol / l (= 6.5 mg / l ).
As already noted, in industrialized regions, various elements, including heavy metals, accumulate in the soil. Near major highways in Europe and North America, the impact on plants of lead compounds entering the air and soil with exhaust gases is very noticeable. Part of the lead compounds enters through the leaves into plant tissues. Numerous studies have established an increased content of lead in plants and soil at a distance of up to 50 m away from highways. There have been cases of poisoning of plants in places of particularly intense exposure to exhaust gases, for example, firs at a distance of up to 8 km from the major Munich airport, where about 230 aircraft sorties are made per day. Spruce needles contained 8-10 times more lead than needles in uncontaminated areas.
Compounds of other metals (copper, zinc, cobalt, nickel, cadmium, etc.) noticeably affect plants near metallurgical enterprises, coming both from the air and from the soil through the roots. In such cases, it is especially important to study and implement techniques that prevent excessive intake of toxic elements into plants. So, in Finland, the content of lead, cadmium, mercury, copper, zinc, manganese, vanadium and arsenic was determined in the soil, as well as lettuce, spinach and carrots grown near industrial facilities and highways and in clean areas. Wild berries, mushrooms and meadow herbs were also studied. It was found that in the area of operation of industrial enterprises, the lead content in lettuce ranged from 5.5 to 199 mg/kg of dry weight (background 0.15-3.58 mg/kg), in spinach - from 3.6 to 52.6 mg /kg dry weight (background 0.75-2.19), in carrots - 0.25-0.65 mg/kg. The content of lead in the soil was 187-1000 mg/kg (background 2.5-8.9). The content of lead in mushrooms reached 150 mg/kg. With distance from highways, the content of lead in plants decreased, for example, in carrots from 0.39 mg/kg at a distance of 5 m to 0.15 mg/kg at a distance of 150 m. The content of cadmium in the soil varied within 0.01-0 .69 mg / kg, zinc - 8.4-1301 mg / kg (background concentrations were 0.01-0.05 and 21.3-40.2 mg / kg, respectively). It is interesting to note that liming the contaminated soil reduced the cadmium content in lettuce from 0.42 to 0.08 mg/kg; potash and magnesium fertilizers did not have a noticeable effect on it.
In areas of severe pollution, the content of zinc in herbs was high - 23.7-212 mg/kg dry weight; arsenic content in soil is 0.47-10.8 mg/kg, in lettuce - 0.11-2.68, spinach - 0.95-1.74, carrots - 0.09-2.9, wild berries - 0 ,15-0.61, mushrooms - 0.20-0.95 mg/kg of dry matter. The content of mercury in cultivated soils was 0.03-0.86 mg/kg, in forest soils- 0.04-0.09 mg/kg. No noticeable differences in the mercury content in different vegetables were found.
The effect of liming and flooding of fields on reducing the intake of cadmium into plants is noted. For example, the content of cadmium in top layer soil of rice fields in Japan is 0.45 mg/kg, and its content in rice, wheat and barley on uncontaminated soil is 0.06 mg/kg, 0.05 and 0.05 mg/kg, respectively. The most sensitive to cadmium is soybean, in which a decrease in the growth and weight of grains occurs when the content of cadmium in the soil is 10 mg/kg. The accumulation of cadmium in rice plants in the amount of 10–20 mg/kg causes suppression of their growth. In Japan, the MPC for cadmium in a grain of rice is 1 mg/kg.
In India, there is a problem of copper toxicity due to its large accumulation in soils located near the copper mines in Bihar. Toxic level of EDTA-Cu citrate > 50 mg/kg of soil. Indian scientists also studied the effect of liming on the copper content in drainage water. Lime rates were 0.5, 1 and 3 of the required for liming. Studies have shown that liming does not solve the problem of copper toxicity, since 50-80% of the precipitated copper remained in a form available to plants. The content of available copper in soils depended on the rate of liming, initial content of copper in drainage water, and soil properties.
Studies have found that typical symptoms of zinc deficiency were observed in plants grown in a nutrient medium containing this element 0.005 mg/kg. This led to the suppression of plant growth. At the same time, zinc deficiency in plants contributed to a significant increase in the adsorption and transport of cadmium. With an increase in the concentration of zinc in the nutrient medium, the entry of cadmium into plants sharply decreased.
Of great interest is the study of the interaction of individual macro - and microelements in the soil and in the process of plant nutrition. Thus, in Italy, the effect of nickel on the entry of phosphorus (32 P) into the nucleic acids of young maize leaves was studied. Experiments have shown that a low concentration of nickel stimulated, while a high one inhibited the growth and development of plants. In the leaves of plants grown at a nickel concentration of 1 μg/L, the entry of 32 P into all fractions of nucleic acids was more intense than in the control. At a nickel concentration of 10 μg/L, the entry of 32 P into nucleic acids significantly decreased.
From numerous research data, it can be concluded that in order to prevent the negative effect of fertilizers on fertility and soil properties, a scientifically based fertilizer system should provide for the prevention or weakening of possible negative phenomena: acidification or alkalization of the soil, deterioration of its agrochemical properties, non-exchange absorption of nutrients, chemical absorption of cations , excessive mineralization of soil humus, mobilization of an increased amount of elements, leading to their toxic effect, etc.
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