Mineral fertilizers: benefits and harms. The influence of mineral and organic fertilizers and other methods of mobilizing fertility on the agrochemical parameters of soils. The negative effect of fertilizers on the soil
All mineral fertilizers, depending on the content of the main nutrients, are divided into phosphorus, nitrogen and potash. In addition, complex mineral fertilizers containing a complex of nutrients are produced. The raw material for the production of the most common mineral fertilizers (superphosphate, saltpeter, sylvinite, nitrogenous fertilizers, etc.) are natural (apatites and phosphorites), potassium salts, mineral acids, ammonia, etc. Technological processes obtaining mineral fertilizers are varied, more often they use the method of decomposition of phosphorus-containing raw materials with mineral acids.
The main factors in the production of mineral fertilizers are the high dust content of the air and its pollution with gases. Dust and gases also contain its compounds, phosphoric acid, nitric acid salts and other chemical compounds that are industrial poisons (see Industrial poisons).
Of all the substances that make up mineral fertilizers, the most toxic compounds are fluorine (see), (see) and nitrogen (see). Inhalation of dust containing mineral fertilizers leads to the development of catarrh of the upper respiratory tract, laryngitis, bronchitis, (see). With prolonged contact with the dust of mineral fertilizers, chronic intoxication of the body is possible, mainly as a result of the influence of fluorine and its compounds (see). The group of nitrogen and complex mineral fertilizers can provide bad influence on the body in connection with methemoglobin formation (see Methemoglobinemia). Measures for the prevention and improvement of working conditions in the production of mineral fertilizers consist in sealing dusty processes, arranging a rational ventilation system (general and local), mechanization and automation of the most labor-intensive stages of production.
Personal prevention measures are of great hygienic importance. All workers at enterprises for the production of mineral fertilizers must be provided with overalls. For work accompanied by a large emission of dust, overalls are used (GOST 6027-61 and GOST 6811 - 61). Dust removal and disposal of workwear is mandatory.
An important measure is the use of anti-dust respirators ("Petal", U-2K, etc.) and goggles. To protect the skin, you should use protective ointments (IER-2, Chumakov, Selissky, etc.) and indifferent creams and ointments (silicone cream, lanolin, petroleum jelly, etc.). Personal precautions also include daily shower, hand washing and before meals.
Those working in the production of mineral fertilizers must undergo obligatory X-ray examination of the skeletal system with the participation of a therapist, neuropathologist, otolaryngologist at least twice a year.
Mineral fertilizers are chemicals that are applied to the soil in order to obtain high and sustainable yields. Depending on the content of the main nutrients (nitrogen, phosphorus and potassium), they are divided into nitrogen, phosphorus and potash fertilizers.
The raw materials for obtaining mineral fertilizers are phosphates (apatites and phosphorites), potash salts, mineral acids (sulfuric, nitric, phosphoric), nitrogen oxides, ammonia, etc. agriculture is dust. The nature of the impact of this dust on the body, the degree of its danger depend on the chemical composition of fertilizers and their aggregate state... Working with liquid mineral fertilizers (liquid ammonia, ammonia water, ammonia, etc.) is also associated with the release of harmful gases.
The toxic effect of the dust of phosphate raw materials and the finished product depends on the type of mineral fertilizers and is determined by the fluorine compounds included in their composition (see) in the form of salts of hydrofluoric and fluorosilicic acids, phosphorus compounds (see) in the form of neutral salts of phosphoric acid, nitrogen compounds (see) in the form of salts of nitric and nitrous acids, silicon compounds (see) in the form of silicon dioxide in a bound state. The greatest danger is represented by fluorine compounds, which contain from 1.5 to 3.2% in various types of phosphate raw materials and mineral fertilizers. Exposure to dust from phosphate raw materials and mineral fertilizers can cause catarrh of the upper respiratory tract, rhinitis, laryngitis, bronchitis, pneumoconiosis, etc. in workers, which are mainly caused by the irritating effect of dust. The local irritant effect of dust depends mainly on the presence of alkali metal salts in it. With prolonged contact with the dust of mineral fertilizers, chronic intoxication of the body is possible, mainly from exposure to fluorine compounds (see.Fluorosis). Along with the fluorogenic effect, the group of nitrogen and complex mineral fertilizers also has a methemoglobin-forming effect (see Methemoglobinemia), which is due to the presence of salts of nitric and nitrous acids in their composition.
During the production, transportation and application of mineral fertilizers in agriculture, precautions must be taken. In the production of mineral fertilizers, a system of anti-dust measures is carried out: a) sealing and aspiration of dusty equipment; b) dust-free cleaning of premises; c) purification of dust from the air extracted by mechanical ventilation, before its release into the atmosphere. The industry produces mineral fertilizers in granular form, in containers, bags, etc. This also prevents intense dust formation when using fertilizers. To protect the respiratory system from dust, use respirators (see), special clothing (see Clothes, Glasses). It is advisable to use protective ointments, crust (Selissky, IER-2, Chumakov, etc.) and indifferent creams (lanolin, petroleum jelly, etc.) that protect the skin of workers. It is recommended not to smoke during work; rinse your mouth thoroughly before eating and drinking. After work, you need to take a shower. There should be enough vitamins in the diet.
Employees must undergo a medical examination at least twice a year with mandatory X-ray of the skeletal system and chest.
The use of mineral fertilizers (even in high doses) does not always lead to a predicted increase in yield.
Numerous studies indicate that the weather conditions of the growing season have such a strong effect on the development of plants that extremely unfavorable weather conditions actually neutralize the effect of increasing yields even at high doses of nutrients (Strapenyants et al., 1980; Fedoseev, 1985). The utilization rates 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 of increasing the efficiency of mineral fertilizers in areas of unstable agriculture deserve attention.
One of the methods of increasing the efficiency of using nutrients from fertilizers and soil, strengthening the immunity of plants to unfavorable environmental factors and improving the quality of the products obtained is the use of humic preparations in the cultivation of agricultural crops.
Over the past 20 years, interest in humic substances used in agriculture has significantly increased. The topic of humic fertilizers is not new either for researchers or for agricultural practitioners. Since the 50s of the last century, the influence of humic preparations on the growth, development, and yield of various agricultural crops has been studied. At present, due to the sharp rise in the price of mineral fertilizers, humic substances are widely used to increase the efficiency of using nutrients from the soil and fertilizers, increase the immunity of plants to unfavorable environmental factors and improve the quality of the yield of the products obtained.
The raw materials for the production of humic preparations are diverse. It 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, as a result of which surface-active high-molecular organic substances of various masses are released, characterized by a certain spatial structure and physicochemical 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, assimilable or difficult to assimilate forms. The higher the content of organic acids in the humic preparation, the more valuable it is both for individual use and especially for the production of complex fertilizers with humates.
There are various ways of using humic preparations in crop production: seed treatment, foliar 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 decorative cultures 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 phosphorus retrogradation;
- dramatically 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 the structure of soils, 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;
- reduce the vegetative period by improving protein metabolism, concentrated delivery of nutrients to the fruit part 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 plant root system due to adequate 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 agricultural crops and the efficiency of using nutrients by plants" (Fixen, 2010), a reference is made to a systematic analysis of methods for assessing the effectiveness of using nutrients by plants. The intensity of technologies for the cultivation of agricultural crops and the associated changes in the structure and composition of the soil, in particular, the immobilization of nutrients and mineralization are indicated as one of the significant factors affecting the efficiency of the use of nutrients. organic matter... Humic components in combination with key macronutrients, primarily phosphorus, support soil fertility under intensive technologies.
In the work of S.E. Ivanova, I.V. Loginova, T. Tyndall, "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). An increase in the degree of phosphorus use by plants in the year of application has a pronounced ecological effect - a decrease in the ingress of phosphorus with surface and underground runoff into water bodies. The combination of an organic component in the form of humic substances with a mineral one in fertilizers prevents the chemical fixation of phosphorus into poorly soluble phosphates of calcium, magnesium, iron and aluminum and preserves phosphorus in a form accessible 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 granular industrial fertilizers, which is widely used in the preparation of mechanical fertilizer mixtures;
- mechanical introduction of humates into powder, followed by granulation during low-tonnage production of mineral fertilizers.
- introduction of humates into the melt during the large-scale production of mineral fertilizers (industrial production).
The use of humic preparations for the production of liquid mineral fertilizers used for foliar processing of crops is very widespread in Russia and abroad.
The purpose of this publication is to show the comparative effectiveness of humatized and conventional granular mineral fertilizers on grain crops (winter and spring wheat, barley) and spring rape in various soil and climatic zones of Russia.
As a humic preparation for obtaining guaranteed high results in terms of agrochemical efficiency, sodium humate "Sakhalinsky" was chosen with the following indicators ( tab. 1).
The production of humate "Sakhalinsky" is based on the use of brown coals from the Solntsevskoye deposit about. Sakhalin, which has a very high concentration of humic acids in an assimilable form (over 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. The product also contains microelements and zeolites, which contribute to the accumulation of nutrients and the regulation of the metabolic process.
In addition to the indicated indicators of sodium humate "Sakhalin", an important factor in its choice as a humic additive was the production of concentrated forms of humic preparations in industrial quantities, high agrochemical indicators of individual use, the content of humic substances mainly in a water-soluble form and the presence of a liquid form of humate for uniform distribution in the granule in industrial production, as well as state registration as an agrochemical.
In 2004, OJSC Ammophos in Cherepovets produced a pilot batch of a new type of fertilizer - azophoska (nitroammofoska) grade 13:19:19, with the addition of Sakhalinsky sodium humate (alkaline extract from leonardite) into the pulp according to the technology, developed at JSC NIUIF. Quality indicators of humatized ammophoska 13:19:19 are given in tab. 2.
The main task in industrial testing was to justify the best way introduction of the humate additive "Sakhalinsky" while maintaining the water-soluble form of humates in the product. It is known that humic compounds in acidic media (at pH<6) переходят в формы водорастворимых гуматов (H-гуматы) с потерей их эффективности.
The introduction of powdery humate "Sakhalin" into the recycle during the production of complex fertilizers ensured the absence of contact of humate 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. No deterioration of physical and chemical complex fertilizers (caking, granule strength, dust content) was noted in the presence of a humic component. The hardware design of the humate injection unit was also not difficult.
In 2004, in ZAO Set-Orel Invest (Oryol region), a production experiment was carried out with the introduction of humated ammophoska under barley. The increase in barley yield on an area of \u200b\u200b4532 hectares from the use of humatized fertilizer in comparison with 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, in the State Unitary Enterprise OPKh "Orlovskoe" VNII of leguminous and cereal crops (Oryol region), field experiments were carried out to study the effect of humatized and ordinary 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 with the introduction of an increased dose of humated fertilizer. In the same variant, the highest protein and gluten content in the grain was observed. As in the experiment with winter wheat, the application of the humated fertilizer significantly increased the yield and the content of protein and gluten in the grain compared to the application of the same dose of standard fertilizer. The latter works not only as an individual component, but also improves the assimilation of phosphorus and potassium by plants, reduces nitrogen losses in the nitrogen nutrition cycle, and generally improves exchange between soil, soil solutions and plants.
A significant improvement in the quality of the harvest of both winter and spring wheat indicates an increase in the efficiency of the 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 low content (from tenths to 1%), humate additives and trace elements provide almost the same increase in yield and quality of agricultural products. In the work (Aristarkhov, 2010), the effect of trace elements on the yield and quality of grain of cereals and legumes was studied and an increase in protein and gluten was shown using the example of winter wheat with the main application on various types of soils. The directional influence of trace elements and humates on the productive part of crops is comparable in terms of the results obtained.
High agrochemical results of production with minimal refinement of the instrumental scheme of large-scale production of complex fertilizers, obtained from the use of humated ammophoska (13:19:19) with sodium humate "Sakhalin", made it possible to expand the range of humated brands of complex fertilizers with the inclusion of nitrate-containing brands.
In 2010, Mineralnye udobrenia OJSC (Rossosh, Voronezh region) produced a batch of humatized azophoska 16:16:16 (N: P 2 O 5: K 2 O) with a humate content (alkaline extract from leonardite) - not less than 0.3% and moisture - not more than 0.7%.
Azophoska with humates was a granular organic mineral fertilizer of light gray color, which differs from the standard 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 organomineral fertilizer for the main and "pre-sowing" application to the soil and for root dressing for all crops where it is possible to use the usual Azofoska.
In 2010 and 2011. On the experimental field of the GNU Moscow Research Institute of Agriculture "Nemchinovka", studies were carried out with the humatized Azofos production of OJSC "Mineral Fertilizers" in comparison with the standard one, as well as with potassium fertilizers (potassium chloride) containing humic acids (Kaligum), in comparison with the traditional potassium fertilizer KCl.
Field experiments were carried out according to the generally accepted technique (Dospekhov, 1985) on the experimental field of the Moscow Research Institute of Agriculture "Nemchinovka".
A distinctive feature of the soils of the experimental site is a high phosphorus content (about 150-250 mg / kg), and an average potassium (80-120 mg / kg). This led to the rejection of the main application of phosphorus 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, Р 2 О 5 and К 2 О (according to Kirsanov) - 156 and 88 mg / kg, respectively, CaO - 1589 mg / kg, MgO - 474 mg / kg.
In the experiment with Azofoskaya and rapeseed, the size of the experimental plot was 56 m 2 (14m x 4m), the replication was four times. Pre-sowing soil cultivation after the main fertilization - by a cultivator and immediately before sowing - by an RBK (rotary harrow-cultivator). Sowing - with an Amazon seeder in optimal agrotechnical terms, the seeding depth is 4-5 cm - for wheat and 1-3 cm - for rapeseed. Seeding rates: wheat - 200 kg / ha, rapeseed - 8 kg / ha.
In the experiment we used spring wheat variety MIS and spring rape variety Podmoskovny. The MIS variety is a highly productive mid-ripening variety that makes it possible 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 rape near Moscow - mid-season, the growing season is 98 days. Environmentally plastic, characterized by uniform flowering and maturation, lodging resistance 4.5-4.8 points. The low content of glucosinolates in the seeds allows the use of oilcake and meal in the diets of animals and poultry at higher rates.
Wheat was harvested in the phase of full grain ripeness. Rape was mowed for green forage during the flowering phase. Experiments for spring wheat and rapeseed were laid 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 of a.i. NPK / ha
Background + Azophoska with humate, the main application is 30 kg a.i. NPK / ha
Background + azophoska main application 60 kg of a.i. NPK / ha
Background + azophoska with humate, the main application is 60 kg a.i. NPK / ha
Background + Azophoska main application is 90 kg a.i. NPK / ha
Background + azophoska with humate, the main application is 90 kg a.i. NPK / ha
During the years of the research, the weather conditions significantly differed from the long-term average for the Non-Black Earth 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, in the Moscow region from the beginning of July until the harvest of wheat in early August, there was a prolonged drought. Average daily temperatures during this period were exceeded by 7 о С, and daytime temperatures for a long time were above 35 о С. Some short-term precipitation fell in the form of heavy rains and water flowed down with surface runoff and evaporated, only partially absorbing into the soil. Soil saturation with moisture in short periods of rains did not exceed the penetration depth of 2-4 cm. In 2011, in the first ten days of May, after sowing and during plant emergence, 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 о С) was significantly higher than the average daily long-term temperature (10.6 о С). The amount of precipitation and air temperature in the 2nd and 3rd decades of May did not differ significantly from the amount of weighted average precipitation and average daily temperatures.
In June, precipitation fell much less than the average multi-year norm, the air temperature exceeded the daily average by 2-4 o C.
July was hot and dry. In total, during the growing season, precipitation fell 60 mm less than the norm, and the average daily air temperature was about 2 о С 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 decrease in the yield.
Prolonged air and soil drought in 2010 did not give the expected effect from increasing doses of Azofoska. This manifested itself in both wheat and rapeseed.
Moisture deficiency turned out to be the main obstacle in the implementation of the established soil fertility, while the wheat yield in general was two times lower than in a similar experiment in 2009 (Garmash et al., 2011). The yield gains when applying 200, 400 and 600 kg / ha of azofoska (physical weight) were practically the same ( tab. five).
The low wheat yield is mainly due to the puny grain. The mass of 1000 grains in all variants of the experiment was equal to 27 - 28 grams. The data on the structure of the crop for 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 grain weight per ear was 0.7-0.8 grams.
At the same time, in the variants of the experiment with the humatized Azofoska, a significant increase in yield was obtained with an increase in the doses of fertilizers. This is due, first of all, to the better general condition of the plants and the development of a more powerful root system when using humates against the background of the general stress of crops from prolonged and prolonged drought.
A significant effect from the use of humatized azophoska was manifested at the initial stage of the development of rapeseed plants. After sowing rapeseed, a short rain shower followed by high air temperatures formed a dense crust on the soil surface. Therefore, the seedlings on the options with the introduction of the usual Azofoska were uneven and very thinned compared to the options with the humatized Azophoska, which led to significant differences in the yield of green mass ( tab. 6).
In the experiment with potash fertilizers, the area of \u200b\u200bthe experimental plot was 225 m 2 (15 mx 15 m), the experiment was repeated four times, the arrangement of the plots was randomized. Experiment area - 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 ae. per ha. Ammonium nitrate was used as nitrogen fertilizer, potassium chloride and a new fertilizer Caligum were used as potassium 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. Prior to sowing, the seeds were treated with the Vincit dressing agent at the rates recommended by the manufacturer. In the tillering phase, wheat crops were fertilized with ammonium nitrate at the rate of 30 kg of ae. per 1 hectare.
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 (Caligum)
Thus, field experiments have reliably proved the agrochemical efficiency of complex fertilizers with additions of humates, determined by the increase in yield and protein content in grain crops. To ensure these results, the correct choice of 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 is necessary. This makes it possible to achieve a relatively low humate content (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 negative weather and climatic conditions, in particular, to drought, 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 harvests per year to maintain high soil fertility, in particular, in expanding zones with a deficient water balance and arid zones. The high agrochemical efficiency of humatized ammophoska (13:19:19) is determined by the complex action of the mineral and organic parts with an increase in the effect 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 Aleksandrovich - Head of the Market Analysis and Sales Planning Department of PhosAgro-Cherepovets JSC; e-mail:[email protected] .
Garmash Grigory Aleksandrovich - Head of the Analytical Research Laboratory of the Moscow Research Institute of Agriculture Nemchinovka, Candidate of Biological Sciences; e-mail:[email protected] .
Garmash Nina Yurievna - 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 Gumat Group of Companies; e-mail:[email protected] .
Literature
Paul I. Fixen The concept of increasing the productivity of agricultural crops and the efficiency of using nutrients by plants // Plant nutrition: Bulletin of the International Institute of Plant Nutrition, 2010, no. - from. 2-7.
Ivanova S.E., Loginova I.V., Tandell 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. - from. 9-12.
Aristarkhov A.N. et al. Effect of microfertilizers on yield, protein collection and product quality of grain and leguminous crops // Agrochemistry, 2010, no. - from. 36-49.
Strapenyants R.A., Novikov A.I., Strebkov I.M., Shapiro L.Z., Kirikoy Ya.T. Modeling the patterns of the effect of mineral fertilizers on the harvest // Bulletin of S.-kh. Science, 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 basic nutrients by the wheat harvest // Agrochemistry, 1978, No. 8. - P. 150-158.
Derzhavin L.M. The use of mineral fertilizers in intensive farming. Moscow: 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.
Municipal budgetary educational institution "Secondary school named after Dmitry Batiev" p. Gam Ust - Vymsky District, Komi Republic
Work performed by: Isakova Irina, student
Supervisor:, 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 used literature …………………………………………. …………… .10
Introduction
The urgency of the problem
Plants absorb minerals from the soil along with water. In nature, these substances then in one form or another return to the soil after the death of a plant or its parts (for example, after leaf fall). Thus, the circulation of minerals takes place. However, such a return does not occur, since during harvesting, minerals are carried away from the fields. To avoid depletion of the soil, people apply various fertilizers in the fields, gardens and vegetable gardens. Fertilizers improve soil nutrition of plants, improve soil properties. As a result, the yield is increased.
The purpose of the work is: to study the effects of mineral fertilizers on the growth and development of plants.
- 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. Your garden plot helps to save some, and also gives you the opportunity to grow organic products. Therefore, the research results can be used when working in the country and in the garden.
Research methods: study and analysis of literature; conducting experiments; comparison.
Literature review. When writing the main part of the project, the sites, the site "Secret of Dacha", the site "Wikipedia" and others were used. The practical part is based on the work "Simple experiments in botany".
1 Main part
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 depths or industrially obtained chemical compounds, contain basic nutrients (nitrogen, phosphorus, potassium) and trace elements important for vital activity. They are made in special factories and contain nutrients in the form of mineral salts. Mineral fertilizers are divided into simple (one-component) and complex fertilizers. Simple mineral fertilizers contain only one of the main nutrients. These include nitrogen, phosphorus, potash fertilizers, 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. In fruit trees and berry bushes, nitrogen fertilization not only increases the yield, but also improves 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 brought in 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 fertilizers impairs survival rate.
Phosphate fertilizers.
Phosphate fertilizers stimulate the development of the root system of plants. Phosphorus enhances the ability of cells to retain water and thus increases the resistance of plants to drought and low temperatures. With sufficient nutrition, phosphorus accelerates the transition of plants from the vegetative phase to the fruiting season. Phosphorus has a positive effect on the quality of fruits - it helps to increase sugar, fats, proteins in them. Phosphate fertilizers can be applied every 3-4 years.
Potash 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 rate 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 for plants starting in 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 calculation of the amount of nutrients in fertilizers has been made. Solutions of optimal concentrations were prepared. These solutions were used to feed the plants and to observe the growth and development of plants.
Preparation of nutrient solutions.
* Hot water for solution preparation
2 bean sprouts were planted in pots with moistened sand. A week later, they left in each jar one, the best plant. On the same day, solutions of mineral salts prepared in advance were added to the sand.
During the experiment, the optimum air temperature and normal sand were maintained. Three weeks later, the plants were compared to each other.
Experimental results.
Description of plants | Plant height | Number of leaves |
|
Pot number 1 "No salts" | Leaves are pale, dull green in color, beginning to turn yellow. The tips and edges of the leaves turn brown, and small rusty spots appear on the leaf blade. The sheet size is slightly smaller than that of other samples. The stem is thin, inclined, weakly branched. | ||
Pot number 2 "Less salt" | The leaves are pale green. The size of the leaves is medium to large. No visible damage. The stem is thick and branched. | ||
Pot number 3 "More salt" | The leaves are bright green, large. The plant looks healthy. The stem is thick and branched. |
Based on the results of the experiment, the following conclusions can be drawn:
- For normal growth and development of plants, minerals are needed (development of beans in pots No. 2 and No. 3) They can only be absorbed in dissolved form. The full development of plants occurs when using complex fertilizers (nitrogen, phosphorus, potassium). The amount of fertilizer applied should be strictly dosed.
As a result of the experience and study of the literature, some rules for the use of fertilizers were drawn up:
Organic fertilizers cannot fully satisfy plants with nutrients, therefore mineral fertilizers are also added. In order not to harm plants and soil, it is necessary to have basic knowledge of the consumption of nutrients and mineral fertilizers by plants.When using mineral fertilizers, remember the following:
- do not exceed the recommended doses and apply only in those phases of plant growth and development, when necessary; do not allow fertilizer to get on the leaves; carry out liquid dressing after watering, otherwise you can burn the roots; stop any feeding four to ten weeks before harvest to avoid nitrate build-up.
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 yield of any crop. Mineral salts are essential for plant growth and development. Plants look healthy.
Thanks to experience, it became clear that regular fertilizing of plants with fertilizers should become a common procedure, since many disturbances 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 fertilizers in accordance with the appearance and physiological state of the plants.
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 that occur 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.
The most beneficial for the soil are natural fertilizers. 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. Putting needles in 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 and become poisonous to humans and animals. This is especially true for melons and gourds.
The use of iodine fertilizers for feeding outside the root system gives a good effect on vegetables and fruit 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. Alkali binds heavy metals, converting them into salts.
There are other types of fertilizers that allow you to change the structure, acidity, fertility, salinity and other parameters of the soil. The main thing is that when using fertilizers, agrotechnical and environmental standards are not violated.
Kuban State University
Department of Biology
in the discipline "Soil Ecology"
"Latent negative effect of fertilizers."
Performed
Afanasyeva L. Yu.
5th year student
(specialty -
"Bioecology")
Checked by O. V. Bukareva
Krasnodar, 2010
Introduction ……………………………………………………………………………… ... 3
1. The effect of mineral fertilizers on soils ………………………………… ... 4
2. Influence of mineral fertilizers on atmospheric air and water ………… ..5
3. Influence of mineral fertilizers on product quality and human health …………………………………………………………………………………………………………………………………………………………………………………………………
4. Geoecological consequences of fertilization …………………… ... 8
5. Impact of fertilizers on the environment …………………………… ..10
Conclusion …………………………………………………………………………… .17
List of used literature ……………………………………………… ... 18
Introduction
Soil pollution with foreign chemicals causes great damage to them. Chemicalization of agriculture is a significant factor of environmental pollution. Even mineral fertilizers, if used incorrectly, can cause environmental damage with dubious economic benefits.
Numerous studies of agricultural chemists have shown that different types and forms of mineral fertilizers have different effects on the properties of soils. Fertilizers applied to the soil enter into complex interactions with it. All kinds of transformations take place here, which depend on a number of factors: the properties of fertilizers and soil, weather conditions, agricultural technology. The transformation of certain types of mineral fertilizers (phosphorus, potash, nitrogen) determines their influence on soil fertility.
Mineral fertilizers are an inevitable consequence of intensive farming. There are calculations that in order to achieve the desired effect from the use of mineral fertilizers, world consumption should be about 90 kg / year per person. The total production of fertilizers in this case reaches 450-500 million tons / year, while at the present time their world production is equal to 200-220 million tons / year or 35-40 kg / year per person.
The use of fertilizers can be considered as one of the manifestations of the law of increasing energy input per unit of agricultural production. This means that more and more mineral fertilizers are required to obtain the same yield increase. So, at the initial stages of the application of fertilizers, the addition of 1 ton of grain from 1 hectare is provided by the introduction of 180-200 kg of nitrogen fertilizers. The next additional ton of grain is associated with a 2-3 times higher fertilizer dose.
Environmental consequences of the use of mineral fertilizers it is advisable to consider at least three points of view:
The local impact of fertilizers on ecosystems and soils into which they are applied.
Extreme impact on other ecosystems and their links, primarily on the aquatic environment and atmosphere.
Impact on the quality of products obtained from fertilized soils and human health.
1. Influence of mineral fertilizers on soil
In the soil as a system, such changes that lead to loss of fertility:
Acidity rises;
The species composition of soil organisms is changing;
The circulation of substances is disrupted;
The structure is destroyed, impairing other properties.
There is evidence (Mineev, 1964) that an increase in the acidity of soils with the use of fertilizers (primarily acidic nitrogen) is an increased leaching of calcium and magnesium from them. To neutralize this phenomenon, these elements have to be introduced into the soil.
Phosphate fertilizers do not have such a pronounced acidifying effect as nitrogen fertilizers, but they can cause zinc starvation of plants and the accumulation of strontium in the resulting products.
Many fertilizers contain impurities. In particular, their introduction can increase the radioactive background and lead to the progressive accumulation of heavy metals. The main way reduce these consequences - moderate and scientifically sound fertilization:
Optimal doses;
The minimum amount of harmful impurities;
Alternating with organic fertilizers.
It should also be remembered that "mineral fertilizers are a means of masking realities." Thus, there is evidence that more minerals are removed with the products of soil erosion than they are introduced with fertilizers.
2. Influence of mineral fertilizers on atmospheric air and water
The effect of mineral fertilizers on atmospheric air and water is mainly associated with their nitrogen forms. The nitrogen of mineral fertilizers enters the air either in free form (as a result of denitrification) or in the form of volatile compounds (for example, in the form of nitrous oxide N2O).
According to modern concepts, gaseous losses of nitrogen from nitrogen fertilizers amount to 10 to 50% of its application. An effective means of reducing gaseous nitrogen losses is scientifically grounded their application:
Application to the root-forming zone for the fastest absorption by plants;
Use of substances that inhibit gaseous losses (nitropyrine).
The most tangible effect on water sources, in addition to nitrogen, is exerted by phosphorus fertilizers. Fertilizer carry-over to water sources is minimized when applied correctly. In particular, it is unacceptable to spread fertilizers over the snow cover, scatter them from aircraft near water bodies, or store them in the open air.
3. Influence of mineral fertilizers on product quality and human health
Mineral fertilizers can have a negative impact on both plants and the quality of plant products, as well as organisms that consume it. The main of such impacts are presented in tables 1, 2.
With high doses of nitrogen fertilizers, the risk of plant diseases increases. Excessive accumulation of green mass takes place, and the probability of lodging of plants increases sharply.
Many fertilizers, especially chlorine-containing ones (ammonium chloride, potassium chloride), have a negative effect on animals and humans, mainly through the water, where the released chlorine enters.
The negative effect of phosphorus fertilizers is mainly due to the fluorine, heavy metals and radioactive elements they contain. Fluoride, when its concentration in water is more than 2 mg / l, can contribute to the destruction of tooth enamel.
Table 1 - The impact of mineral fertilizers on plants and the quality of plant products
Fertilizers | Effect of mineral fertilizers |
|
positive | negative |
|
At high doses or untimely methods of application - accumulation in the form of nitrates, violent growth to the detriment of stability, increased incidence, especially fungal diseases. Ammonium chloride promotes the accumulation of Cl. The main accumulators of nitrates are vegetables, corn, oats, tobacco. |
||
Phosphoric | Reduce the negative effects of nitrogen; improve product quality; contribute to an increase in plant resistance to diseases. | At high doses, plant toxicosis is possible. They act mainly through the heavy metals (cadmium, arsenic, selenium), radioactive elements and fluorine contained in them. The main stores are parsley, onions, sorrel. |
Potash | Similar to phosphorus. | They act mainly through the accumulation of chlorine when potassium chloride is added. With an excess of potassium - toxicosis. The main accumulators of potassium are potatoes, grapes, buckwheat, greenhouse vegetables. |
Table 2 - The impact of mineral fertilizers on animals and humans
Fertilizers | Main impacts |
| Nitrate forms | Nitrates (MPC for water 10 mg / l, for food - 500 mg / day per person) are reduced in the body to nitrites, which cause metabolic disorders, poisoning, deterioration of immunological status, methemoglobin (oxygen starvation of tissues). When interacting with amines (in the stomach), they form nitrosamines - the most dangerous carcinogens. In children, they can cause tachycardia, cyanosis, loss of eyelashes, rupture of the alveoli. In animal husbandry: vitamin deficiency, a decrease in productivity, the accumulation of urea in milk, an increase in morbidity, a decrease in fertility. |
Phosphoric Superphosphate | They act mainly through fluorine. An excess of it in drinking water (more than 2 mg / l) causes damage to the enamel of the teeth in humans, loss of elasticity of blood vessels. With a content of more than 8 mg / l - osteochondrosis. |
| Potassium chloride Ammonium chloride | Consumption of water with a chlorine content of more than 50 mg / l causes poisoning (toxicosis) in humans and animals. |
4. Geoecological consequences of fertilization
For their development, plants need a certain amount of biogenic substances (nitrogen, phosphorus, potassium compounds), usually absorbed from the soil. In natural ecosystems, biogens assimilated by vegetation return to the soil as a result of destruction processes in the cycle of matter (decomposition of fruits, plant litter, dead shoots, roots). A number of nitrogen compounds are fixed by bacteria from the atmosphere. Some of the nutrients are brought in with precipitation. On the negative side of the balance are infiltration and surface runoff of soluble nutrient compounds, their removal with soil particles in the process of soil erosion, as well as the transformation of nitrogen compounds into a gaseous phase with its release into the atmosphere.
In natural ecosystems, the rate of accumulation or consumption of nutrients is usually low. For example, for the virgin steppe on the chernozems of the Russian Plain, the ratio between the flux of nitrogen compounds across the boundaries of the selected area of \u200b\u200bthe steppe and its reserves in the upper meter layer is about 0.0001% or 0.01%.
Agriculture violates the natural, almost closed balance of nutrients. The annual harvest takes away part of the nutrients contained in the produced product. In agroecosystems, the rate of nutrient removal is 1-3 orders of magnitude higher than in natural systems, and the higher the yield, the relatively greater the removal rate. Consequently, even if the initial supply of nutrients in the soil was significant, in the agroecosystem it can be used up relatively quickly.
In total, with the grain harvest in the world, for example, about 40 million tons of nitrogen is removed per year, or about 63 kg per hectare of grain. Hence, the need to use fertilizers to maintain soil fertility and increase yields, since with intensive farming without fertilizers, soil fertility decreases already in the second year. Usually nitrogen, phosphorus and potash fertilizers are used in various forms and combinations, depending on local conditions. At the same time, the application of fertilizers masks soil degradation by replacing natural fertility with fertility based mainly on chemicals.
The production and consumption of fertilizers in the world has grown steadily, increasing over 1950-1990. approximately 10 times. The world average use of fertilizers in 1993 was 83 kg per hectare of arable land. Hidden behind this average is a large difference in consumption across countries. The Netherlands uses the most fertilizers, and there the level of fertilization has even decreased in recent years: from 820 kg / ha to 560 kg / ha. On the other hand, the average fertilizer consumption in Africa in 1993 was only 21 kg / ha, with 24 countries using 5 kg / ha or less.
In addition to its positive effects, fertilizers also pose environmental problems, especially in countries with a high level of their use.
Nitrates are hazardous to human health if their concentration in drinking water or agricultural products is higher than the established MPC. The concentration of nitrates in water flowing from fields is usually between 1 and 10 mg / l, and from unplowed lands it is an order of magnitude lower. As the weight and duration of fertilizer application increases, more and more nitrates enter surface and groundwater, making them unsuitable for drinking. If the level of application of nitrogen fertilizers does not exceed 150 kg / ha per year, then about 10% of the volume of applied fertilizers gets into natural waters. At higher loads, this proportion is even higher.
In particular, the problem of groundwater pollution after nitrates has entered the aquifer is a serious problem. Water erosion, carrying away soil particles, also transfers phosphorus and nitrogen compounds contained in them and adsorbed on them. If they enter water bodies with slow water exchange, conditions for the development of the eutrophication process are improved. For example, dissolved and suspended nutrient compounds have become the main water pollutants in US rivers.
Agricultural dependence on mineral fertilizers has led to major shifts in global nitrogen and phosphorus cycles. The industrial production of nitrogen fertilizers has disrupted the global nitrogen balance due to a 70% increase in the amount of nitrogen compounds available to plants compared to the pre-industrial period. Excess nitrogen can alter soil acidity and organic matter content, which can lead to further leaching of nutrients from the soil and deterioration of natural water quality.
According to scientists, the washout of phosphorus from the slopes in the process of soil erosion is at least 50 million tons per year. This figure is comparable to the annual industrial production of phosphate fertilizers. In 1990, the same amount of phosphorus was carried by rivers into the ocean as it was introduced into the fields, namely 33 million tons. Since there are no gaseous compounds of phosphorus, it moves under the influence of gravity, mainly with water, mainly from continents to the oceans ... This leads to a chronic deficiency of phosphorus on land and to another global geoecological crisis.
5. Impact of fertilizers on the environment
The negative effect of fertilizers on the environment is primarily associated with imperfect properties and chemical composition of fertilizers. Essential disadvantages of many mineral fertilizers are:
The presence of residual acid (free acidity) due to the technology of their production.
Physiological acidity and alkalinity resulting from the predominant use of cations or anions by plants from fertilizers. Long-term use of physiologically acidic or alkaline fertilizers changes the reaction of the soil solution, leads to the loss of humus, increases the mobility and migration of many elements.
High solubility of fat. In fertilizers, unlike natural phosphate ores, fluorine is in the form of soluble compounds and easily enters the plant. Increased accumulation of fluoride in plants disrupts metabolism, enzymatic activity (inhibits the action of phosphatase), negatively affects protein photo- and biosynthesis, and fruit development. Increased doses of fluorine inhibit the development of animals and lead to poisoning.
Heavy metals (cadmium, lead, nickel). The most contaminated with heavy metals are phosphorus and complex fertilizers. This is due to the fact that almost all phosphorus ores contain large amounts of strontium, rare earths and radioactive elements. The expansion of production and the use of phosphorus and complex fertilizers leads to environmental pollution with fluorine and arsenic compounds.
With existing acidic methods for processing natural phosphate raw materials, the degree of utilization of fluorine compounds in the production of superphosphate does not exceed 20-50%, in the production of complex fertilizers - even less. The fluorine content in superphosphate reaches 1-1.5%, in ammophos 3-5%. On average, about 160 kg of fluoride is supplied to the fields from each ton of phosphorus needed by plants.
However, it is important to understand that it is not the mineral fertilizers themselves as sources of nutrients that pollute the environment, but their accompanying components.
Soluble in soil phosphate fertilizers are largely absorbed by the soil and become inaccessible to plants and do not move along the soil profile. It has been established that the first crop uses only 10-30% of P2 O5 from phosphorus fertilizers, and the rest remains in the soil and undergoes all kinds of transformations. For example, in acidic soils, the phosphorus of superphosphate for the most part is converted into phosphates of iron and aluminum, and in chernozem and in all calcareous soils - into insoluble calcium phosphates. The systematic and long-term use of phosphorus fertilizers is accompanied by the gradual cultivation of the soil.
It is known that long-term use of large doses of phosphorus fertilizers can lead to the so-called "phosphating", when the soil is enriched with assimilable phosphates and new portions of fertilizers have no effect. In this case, excess phosphorus in the soil can disrupt the nutrient ratio and sometimes reduce the availability of zinc and iron to plants. So, in the conditions of Krasnodar Territory on ordinary carbonate chernozems with ordinary application of P2 O5, corn unexpectedly sharply reduced the yield. We had to find ways to optimize the elemental nutrition of plants. Phosphating of soils is a certain stage of their domestication. This is the result of the inevitable process of accumulation of "residual" phosphorus, when fertilizers are applied in an amount exceeding the removal of phosphorus from the crop.
As a rule, this "residual" phosphorus fertilizer is more mobile and more accessible to plants than natural soil phosphates. With the systematic and long-term application of these fertilizers, it is necessary to change the ratio between nutrients, taking into account their residual effect: the dose of phosphorus should be reduced, and the dose of nitrogen fertilizers should be increased.
Potassium fertilizeradded to the soil, like phosphorus, does not remain unchanged. Part of it is in the soil solution, part passes into an absorbed-exchange state, and part turns into a non-exchangeable form that is inaccessible to plants. The accumulation of available forms of potassium in the soil, as well as the transformation into an inaccessible state as a result of prolonged use of potash fertilizers, depends mainly on the properties of the soil and weather conditions. So, in chernozem soils, the amount of assimilable forms of potassium under the influence of fertilization increases, but to a lesser extent than on sod-podzolic soils, since in chernozems the potassium of fertilizers is more converted into a non-exchangeable form. In an area with a large amount of precipitation and with irrigated agriculture, it is possible that potassium fertilizers can be washed out of the root layer of the soil.
In areas with insufficient moisture, in hot climates, where the soils periodically moisten and dry out, intensive processes of potassium fixation of fertilizers by the soil are observed. Under the influence of the fixation of potassium in fertilizers, it passes into a non-exchangeable state, inaccessible to plants. The type of soil minerals and the presence of minerals with a high fixing ability are of great importance for the degree of potassium fixation by soils. These are clay minerals. Chernozems have a greater ability to fix potassium fertilizers than sod-podzolic soils.
Soil alkalinization caused by the addition of lime or natural carbonates, especially soda, increases fixation. The fixation of potassium depends on the dose of fertilizer: with an increase in the dose of applied fertilizers, the percentage of fixation of potassium decreases. In order to reduce the fixation of fertilizers by potassium soils, it is recommended to apply potassium fertilizers to a sufficient depth to prevent drying out and to apply them more often in crop rotation, since soils systematically fertilized with potassium fix it weaker with a new addition. But the fixed potassium of fertilizers, which is in a non-exchangeable state, also participates in plant nutrition, since over time it can pass into an exchange-absorbed state.
Nitrogen fertilizers in terms of interaction with soil, they differ significantly from phosphorus and potash. Nitrate forms of nitrogen are not absorbed by the soil, so they can easily be washed out by atmospheric precipitation and irrigation water.
Ammonia forms of nitrogen are absorbed by the soil, but after nitrification they acquire the properties of nitrate fertilizers. Partially ammonia can be absorbed by the soil without exchange. Non-exchangeable, fixed ammonium is available to plants to a small extent. In addition, the loss of nitrogen in fertilizers from the soil is possible as a result of nitrogen volatilization in free form or in the form of nitrogen oxides. When nitrogen fertilizers are applied, the content of nitrates in the soil changes sharply, since the compounds most easily assimilated by plants come with fertilizers. The dynamics of nitrates in the soil largely characterizes its fertility.
A very important property of nitrogen fertilizers, especially ammonia fertilizers, is their ability to mobilize soil reserves, which is of great importance in the zone of chernozem soils. Under the influence of nitrogen fertilizers, the organic compounds of the soil undergo mineralization faster and turn into forms readily available for plants.
Some nutrients, especially nitrogen in the form of nitrates, chlorides and sulfates, can seep into groundwater and rivers. The consequence of this is the excess of the norms of the content of these substances in the water of wells, springs, which can be harmful to humans and animals, and also leads to an undesirable change in hydrobiocenoses and damages the fish industry. The migration of nutrients from soil to groundwater in different soil and climatic conditions is not the same. In addition, it depends on the types, forms, doses and timing of the fertilizers used.
In the soils of the Krasnodar Territory with a periodically flushed water regime, nitrates are found to a depth of 10 m and more and merge with groundwater. This indicates a periodic deep migration of nitrates and their inclusion in the biochemical cycle, the initial links of which are soil, parent rock, and groundwater. Such a migration of nitrates can be observed in wet years, when the soils are characterized by a leaching water regime. It was during these years that the danger of nitrate pollution of the environment arises when large doses of nitrogen fertilizers are applied before winter. In years with a non-flushing water regime, the supply of nitrates to groundwater completely stops, although residual traces of nitrogen compounds are observed along the entire profile of the parent rock to the groundwater. Their preservation is facilitated by the low biological activity of this part of the weathering crust.
In soils with a non-flushing water regime (southern chernozems, chestnut soils), pollution of the biosphere with nitrates is excluded. They remain closed in the soil profile and are fully included in the biological cycle.
The potential harmful effects of fertilized nitrogen can be minimized by maximizing the use of nitrogen in crops. So, you need to take care that with increasing doses of nitrogen fertilizers, the efficiency of using their nitrogen by plants increases; there was not a large amount of unused plants of nitrates, which are not retained by the soil and can be washed out by sediments from the root layer.
Plants tend to accumulate nitrates in their organisms, which are contained in the soil in excess quantities. Plant productivity is growing, but the production is poisoned. Vegetable crops, watermelons and melons accumulate nitrates especially intensively.
In Russia, MPCs for plant nitrates are adopted (Table 3). The permissible daily intake (ADI) for a person is 5 mg per 1 kg of body weight.
Table 3 - Acceptable levels of nitrates in foods
vegetable origin, mg / kg
Product | Priming |
|
open | protected |
|
Potatoes | ||
White cabbage | ||
Beetroot | ||
Leafy vegetables (lettuce, spinach, sorrel, cilantro, lettuce, parsley, celery, dill) | ||
Sweet pepper | ||
Table grapes | ||
Baby food (canned vegetables) | ||
Nitrates themselves do not have a toxic effect, but under the influence of some intestinal bacteria, they can turn into nitrites, which have significant toxicity. Nitrites, combining with blood hemoglobin, convert it into methemoglobin, which prevents the transfer of oxygen through the circulatory system; a disease develops - methemoglobinemia, which is especially dangerous for children. Symptoms of the disease: fainting, vomiting, diarrhea.
New ways to reduce the loss of nutrients and limit their pollution of the environment :
To reduce nitrogen losses from fertilizers, slow-acting nitrogen fertilizers and nitrification inhibitors, films, additives are recommended; the encapsulation of fine-grained fertilizers with shells of sulfur and plastics is introduced. The even release of nitrogen from these fertilizers eliminates the accumulation of nitrates in the soil.
The use of new, highly concentrated, complex mineral fertilizers is of great importance for the environment. They are characterized by the fact that they are devoid of ballast substances (chlorides, sulfates) or contain a small amount of them.
Certain facts of the negative impact of fertilizers on the environment are associated with errors in the practice of their application, with insufficiently substantiated methods, timing, and rates of their application without taking into account the properties of the soil.
The hidden negative effect of fertilizers can manifest itself by its effect on soil, plants, environment. When compiling a calculation algorithm, the following processes must be taken into account:
1. Effect on plants - a decrease in the mobility of other elements in the soil. As ways to eliminate negative consequences, the regulation of effective solubility and effective constant of ion exchange is used, due to changes in pH, ionic strength, complexation; foliar feeding and the introduction of nutrients into the root zone; regulation of plant selectivity.
2. Deterioration of the physical properties of soils. As ways to eliminate negative consequences, the forecast and balance of the fertilizer system are used; structure formers are used to improve the structure of the soil.
3. Deterioration of soil water properties. The forecast and balance of the fertilizer system are used as ways to eliminate the negative consequences; components that improve the water regime are used.
4. Decrease in the intake of substances into plants, competition for absorption by the root, toxicity, change in the charge of the root and root zone. As ways to eliminate negative consequences, a balanced fertilizer system is used; foliar feeding of plants.
5. Manifestation of imbalance in root systems, violation of metabolic cycles.
6. The emergence of imbalance in the leaves, violation of metabolic cycles, deterioration of technological and taste qualities.
7. Toxicity of microbiological activity. As ways to eliminate negative consequences, a balanced fertilizer system is used; increased soil buffering; introduction of food sources for microorganisms.
8. Toxicity of enzymatic activity.
9. Toxicity of the animal world of the soil. As ways to eliminate negative consequences, a balanced fertilization system is used; increased soil buffering.
10. Reducing adaptation to pests and diseases, extreme conditions, due to overfeeding. Optimization of the ratio of nutrients is recommended as measures to eliminate negative consequences; regulation of fertilizer doses; integrated plant protection system; the use of foliar feeding.
11. Losses of humus, changes in its fractional composition. To eliminate the negative consequences, the application of organic fertilizers, the creation of a structure, the optimization of pH, the regulation of the water regime, and the balance of the fertilizer system are used.
12. Deterioration of the physical and chemical properties of soils. Ways of elimination - optimization of the fertilizer system, the introduction of ameliorants, organic fertilizers.
13. Deterioration of the physical and mechanical properties of soils.
14. Deterioration of the soil air regime. To eliminate the negative effect, it is necessary to optimize the fertilizer system, introduce ameliorants, and create the soil structure.
15. Soil fatigue. It is necessary to balance the fertilization system, strictly follow the crop rotation plan.
16. The emergence of toxic concentrations of individual elements. To reduce the negative impact, it is necessary to balance the fertilizer system, increase the buffering capacity of soils, precipitate and remove individual elements, and complexation.
17. Increase in the concentration of individual elements in plants above the permissible level. It is necessary to reduce fertilizer rates, balance the fertilizer system, foliar top dressing in order to compete with the entry of toxicants into plants, and introduce toxicant antagonists into the soil.
The main the reasons for the appearance of a latent negative effect of fertilizers in soils are:
Unbalanced use of various fertilizers;
Excess of applied doses in comparison with the buffer capacity of individual components of the ecosystem;
Targeted selection of forms of fertilizers for certain types of soil, plants and environmental conditions;
Incorrect fertilization timing for specific soils and environmental conditions;
The introduction of various toxicants along with fertilizers and ameliorants and their gradual accumulation in the soil above the permissible level.
Thus, the use of mineral fertilizers is a fundamental transformation in the sphere of production in general and, most importantly, in agriculture, which makes it possible to fundamentally solve the problem of food and agricultural raw materials. Agriculture is now unthinkable without the use of fertilizers.
With proper organization and control of application, mineral fertilizers are not hazardous to the environment, human and animal health. Optimal, scientifically based doses increase crop yields and increase production.
Conclusion
Every year, the agro-industrial complex is increasingly resorting to the help of modern technologies in order to increase soil productivity and crop yields, without thinking about what impact they have on the quality of a particular product, human health and the environment as a whole. Unlike farmers, ecologists and doctors around the world question the excessive enthusiasm for biochemical novelties, which literally occupied the market today. Fertilizer manufacturers describe the advantages of their own invention, without mentioning that improper or excessive fertilization can have a detrimental effect on the soil.
Experts have long established that an excess of fertilizers leads to a violation of the ecological balance in soil biocenoses. Chemical and mineral fertilizers, especially nitrates and phosphates, degrade the quality of food products, and also significantly affect human health and the stability of agrocenoses. Ecologists are especially concerned that biogeochemical cycles are disturbed in the process of soil pollution, which subsequently leads to an aggravation of the general ecological situation.
List of used literature
1. Akimova TA, Khaskin VV Ecology. Man - Economy - Biota - Environment. - M., 2001
2. Valkov VF, Shtompel Yu. A., Tyulpanov VI Soil science (soils of the North Caucasus). - Krasnodar, 2002.
3. Golubev GN Geoecology. - M, 1999.
