Phosphorus-containing Fertilizers Research Articles

Study and mechanism of formation of phosphorus production waste in Kazakhstan

Abstract This article contains information about the accumulated industrial waste from phosphorus production and methods for its recycling and disposal to produce marketable products. Monitoring of cottrel dust’s impact on the environment, namely, ground and surface water, soil, and atmosphere was carried out. The mechanism of formation of cottrel dust was studied. The dispersed, chemical, and phase compositions of the dust in furnace gases during the electrothermal smelting of phosphorites were determined. The sequence of chemical reactions during the formation of cottrel dust was elucidated. The ratios of initial components entering the chemical reaction and the thermodynamic parameters (Gibbs energy) were determined using the Chemistry HSC-6 software package. IR spectral and elemental analyses were carried out for determining cottrel dust’s functional groups and elemental composition. Based on modern instrumental studies, it was found that the total content of phosphorus(v) oxide in cottrel dust was 30.7%. This content of phosphorus(v) oxide is sufficient to use cottrel dust as an initial raw material for producing phosphorus-containing fertilizers. This method was proposed for processing cottrel dust to produce monocalcium phosphate on a production scale. The chemical composition of the resulting monocalcium phosphate was determined and confirmed by analytical methods. The proposed technology for producing monocalcium phosphate from cottrel dust is recommended for use in the agro-industrial complex.

Acid-Free Processing of Phosphorite Ore Fines into Composite Fertilizers Using the Mechanochemical Activation Method

The relevance of involving substandard raw materials for the production of composite phosphorus-containing fertilizer production is significant due to the problem of providing food products for the growing population of the Earth. The main raw materials for phosphorus and composite phosphorus-containing fertilizer production are natural phosphate ores—phosphorites. However, in the process of mining and crushing, ~55–60% phosphorite ore fines are formed—a fraction of less than 10 mm, which is unsuitable for traditional processing into composite phosphorus-containing fertilizers. This article presents the results of physicochemical studies of the substandard fine fraction of phosphorite ore and the results of the studies of the possibility of their direct processing into phosphorus and composition of phosphorus-containing fertilizers using methods of mechanical and mechanochemical activation in the “Activator 4” planetary mill. The findings of the studies performed confirm the rather high efficiency of phosphorite ore fines’ mechanical activation and phosphorite-containing mixtures’ mechanochemical activation, which make it possible to significantly increase the content of assimilable phosphorus pentoxide P2O5 in composite phosphorus-containing fertilizers. The proposed innovative technology has fundamental differences from existing technologies, since the mechanochemical activation of a mixture of phosphorite ore fines and functional components will allow for direct acid-free and waste-free processing into phosphorus and composite phosphorus-containing mineral fertilizers.

Response of tef yield and yield components to nitrogen and phosphorus fertilizers.

The challenge facing Ethiopian farmers are the combination of low soil fertility and reduced agricultural productivity. The study aimed to quantify nitrogen and phosphorus-containing fertilizers for tef production in Sekota and Lasta-Lalibela districts, using four nitrogen and three phosphorus levels from urea and triple super phosphate sources. The Results showed that nitrogen and phosphorus fertilizers significantly affected tef yield and yield components. Application of nitrogen at the rate of 92 kg ha-1 increased tef grain yield by 131.01%, 87.78% and 182.23% in Woleh, Sayda and Lasta Lalibela districts, respectively, compared to control treatment. Similarly, 23 kg ha-1 phosphorus increased tef grain yield by 7.42 and 8.52% in Woleh and Lasta Lalibela, respectively. In Lalibela and Woleh, the application of 92 kg N ha-1 resulted in a maximum net benefits of 2099.6 and 2007 United States Dollar (USD) respectively. Furthermore, in Sayda, the application of 92 kg N ha-1 and 23 kg P2O5 ha-1 yielded a net benefit of 1812.55 USD. The marginal rate of return (MRR) from these applications was 539.6% in Lalibela, 781% in Woleh and 352.44% in Sayda. Therefore, application of 92 N and 23 kg P2O5 ha-1 is appropriate for maximum tef production in Sekota and Lasta districts of Amhara region. Further research and extension services should focus on promoting the adoption of these optimized fertilizer practices among smallholder farmers to maximize the sustainable production of tef.

Solubility in manganese sulfate-ammonium sulfate-water system

The production of phosphorus-containing fertilizers involves the use of mineral acids and phosphate raw materials. In the production process and finished fertilizers, the existence of calcium phosphates, ammonium, sulfuric or nitric and phosphoric acids is possible. Enriched superphosphate contains monocalcium phosphate, calcium sulfate dihydrate, phosphoric acid. During ammoniation, monoammonium phosphate can also be formed. The solubility of the components in the manganese sulfate-ammonium sulfate-water system was studied by the visual-polythermal method in the temperature range from -1.0°С to 27.0°С. The phase diagram limits the regions of ice crystallization, ammonium sulfate, manganese sulfate and chemical compound. A solubility diagram was plotted and a new compound (ammonium sulfate + marganes sulfate + water) (NH4)2Mn(SO4)2*6H2O was isolated. The new compound was identified by chemical, X-ray diffraction, thermogravimetric and IR spectroscopic analyses. To physicochemically substantiate the behavior of marganese sulfate under the conditions of production of enriched superphosphate, the interaction of marganese sulfate with monocalcium phosphate was studied by the method of isomolar series in 0.01 M solutions.

Повышение качества и расширение ассортимента продуктов на основе технического монокальцийфосфата

Production of a low-grade phosphate raw materials-based line of products using economically and environmentally appropriate hydrochloric-phosphorus acid technology is a promising area. A double superphosphate (P2O5 = 46 wt. %) was obtained by isothermal re-crystallization due to removing iron(III) from impurities of the technical monocalcium phosphate (P2O5 = 35 wt. %). The obtained product is represented exclusively by a mobile (water-soluble) phosphorus form. The development of greenhouses and requirements for closed soils impose strict restrictions on the impurities composition in the mineral fertilizers. The current State standards regulate such physico-chemical and physico-mechanical parameters of phosphorus-containing fertilizers as nutrients’ concentration, moisture content, pH of 10% solution, granulometric composition, granules’ strength, friability, heavy metals’ concentration. But they ignore a number of impurities, for example, iron(III), that can lead to phosphorus retrogradation. The simple enough technology makes it possible to obtain cheap effective product –monocalcium phosphate (MCP) – from low-grade ores (phosphorites). This explains the high demand for it among farmers. MCP can also be used in animal husbandry, provided that the sanitary regulations and norms requirements on MPC of controlled impurities are met. The development of the “Green Chemistry” involves the use of water-soluble fertilizers and eliminates the toxic elements content that can accumulate in the soil. The iron(III) extracted from impurity minerals binds to phosphorus and forms FePO4 with the citrate-soluble form of P2O5, thereby reducing its mobile form (P2O5 wat.) in the product. A more concentrated product corresponding to the double superphosphate in the main component (P2O5 wat.) content was produced by isothermal re-crystallization of MCP with ballast impurity. In addition, the final product was purified from iron compounds to trace amounts. Thus, purification of technical MCP by isothermal recrystallization method due to the removal of iron impurities to trace amounts expands the field of its application.

Phosphate in Aqueous Solution Adsorbs on Limestone Surfaces and Promotes Dissolution

The use of large quantities of phosphorus-containing fertilizers has resulted in an increase in phosphorus content in the groundwater system, and phosphorus can be adsorbed on the surface of carbonate rocks, affecting their dissolution process and thus carbon sequestration and sink enhancement in carbonate rocks. Therefore, in this study, limestone was exposed to 2 mg/L and 100 mg/L phosphate solutions for 12 d through static batch adsorption experiments. The hydrochemical results showed that in 100 mg/L phosphate solution, a substitution reaction occurred to produce CaHPO4 precipitate, while the concentration of each ion in 2 mg/L phosphate solution was relatively stable and in dynamic equilibrium; combined with XRD and XPS analyses, the main mechanism of phosphate adsorption may be chemical precipitation, which is preferentially adsorbed to Ca sites on carbonate rocks, and the surface deposits are mainly CaHPO4 and a small amount of Mg2PO4(OH). The FTIR spectra were obtained in the range of 1040 cm−1–1103 cm−1 for observed phosphate vibrations, and the υ3 (asymmetric stretching) mode was more significant in the experimental group with a higher phosphate concentration. Raman spectra located near 149 cm−1 and 275 cm−1 involved Ca2+ or Mg2+ relative translations and vibrations, corroborating the FTIR spectroscopic results; a combination of XRD, XPS, FTIR, and Raman spectra confirmed that phosphate adsorption on limestone may be due to the interaction of electrostatic, chemical precipitation, and ligand exchange mechanisms. In addition, the SEM-EDS results showed that, with the combined effect of the water–rock chemical reaction and physical adsorption, metal–phosphorus phase precipitation was formed on the limestone surface, which promoted the dissolution of limestone and may have an unfavorable effect on the carbon sequestration and sinking of carbonate rocks.

STUDY OF THE INFLUENCE OF NITRIC ACID ENRICHMENT OF PHOSPHORITES OF THE CENTRAL KYZYLKUM ON THE PROCESS OF OBTAINING PHOSPHORUS-CONTAINING FERTILIZERS BASED ON THEM

An analysis of the literature shows that natural phosphates are suitable for de-composition with nitric acid, which does not contain significant amounts of cal-cium carbonate, magnesium carbonate and silicates, iron and aluminium com-pounds, which are easily decomposable acids, and as a result, complicate the processing of phosphates and degrade the quality of fertilizers. The best way to obtain phosphorus-containing fertilizers is the phosphoric acid decomposition of phosphate raw materials.

Methods for Obtaining Phosphorus-Containing Fertilizers Based on Industrial Waste

This article discusses the method of obtaining phosphorus-containing components from cottrel dust from the industrial wastes of the New-Jambul phosphorus plant. Accumulated industrial waste heavily pollutes the environment and has a direct impact on all living things. Therefore, their processing is of special interest for the state and grant programs have been allocated in order to obtain new valuable substances. In order to solve these problems, a number of experimental works have been carried out to study the chemical and mineralogical composition and chemical structures during the heat treatment of cottrel dust—the waste of phosphorus production. The optimal parameters of the process of obtaining mono-calcium phosphate from cottrel dust were determined and the process of crystallization of mono-calcium phosphate was studied. A method has been developed for obtaining a phosphorus-containing fertilizer based on cottrel dust from the industrial waste of the New-Jambul phosphorus plant by means of sulfuric acid solutions. The advantage of the resulting phosphorus-containing fertilizer is that it has a high solubility and digestibility of phosphorus plants. They are also high in phosphorus-containing substances that ensure the growth and yield of agricultural plants. The developed method for obtaining phosphorus-containing fertilizers is aimed at reducing the accumulated industrial waste, which in turn allows you to regulate and improve the environmental situation in the region.

Industrial and environmental safety in the extractive natural resource management for the needs of agriculture

The development of agriculture, primarily crop production, is determined by the availability of the necessary amount of phosphorus-containing fertilizers. In order to meet the needs of agriculture in phosphorus mineral fertilizers, extractive nature management is carried out in a number of regions of the world through the extraction and processing of apatite and phosphorite ores. At the same time, it is important to ensure the minimum permissible impact on the environment and natural water systems. For these purposes, methodological approaches are proposed, through which it is possible to monitor the state of objects and processes of mining production and take timely measures to ensure industrial and environmental safety. The author proposes a structure for complex research and monitoring of objects and processes in extractive nature management, based on the integration of interdisciplinary research related to the earth’s surface.

ОЦЕНКА ДИНАМИКИ ОСНОВНЫХ АГРОХИМИЧЕСКИХ ПОКАЗАТЕЛЕЙ КАШТАНОВЫХ ПОЧВ НА ОРОШЕНИИ В УСЛОВИЯХ РИСКОВАННОГО ЗЕМЛЕДЕЛИЯ СТАВРОПОЛЬЯ

Irrigation is an important element of agricultural production in the arid conditions of the Stavropol Territory. The combination of irrigation, chemicalization and complex mechanization provides highly productive use of land that requires specific scientific support. The purpose of the research is to identify differences in the dynamics of the main agrochemical indicators (organic matter, pH, mobile phosphorus, mobile potassium) on irrigated and non-irrigated chestnut soils. The object of research is chestnut soils located in an extremely arid climatic zone of the Stavropol Territory. The data of complex monitoring of soil fertility in the Apanasenkovsky district were used as the source material. The data for the period from 1991 to 2020 were prepared by the staff of the State Center for Agrochemical Service “Stavropolsky”. The content of soil organic matter was determined by the Tyurin method in the modification of CINAO. Mobile compounds of phosphorus and potassium were determined by the Machigin method in the modification of CINAO. The value of the hydrogen pH index of the aqueous suspension was determined by the potentiometric method. The content of organic matter in chestnut soils increased from 1.8 to 2.0–2.1% both on irrigated and non-irrigated lands. A tendency to leaching of irrigated lands by 0.2 units has been revealed; therefore, in this case, it is recommended to use chemical ameliorants. Moreover, on irrigation, an increase in the content of mobile phosphorus (from 0.8 to 4.0 mg/kg) compared to non-irrigated areas was revealed. The reason for this is the increased doses of phosphorus-containing fertilizers applied during irrigation. During the study period, the content of mobile potassium increased from 77 to 93 mg/kg irrigated chestnut soils compared to non-irrigated ones. The negative dynamics in the content of mobile potassium on irrigation was revealed. It amounted to 364 mg/kg (as of 2020), which is lower than the data of the previous survey period by 81 mk/kg. Particular attention should be paid to the use of potash fertilizers since there is increased removal of this element, despite the high potash potential of chestnut soils in the arid zone of the Stavropol Territory.

Nutrient regime of irrigated meadow-chernozem soils under long-term intensive use

The patterns of phosphorus and potassium status of soils were studied given the improvement of agricultural technologies of irrigated agriculture. Long-term studies were carried out in an experimental grain-grass crop rotation on irrigated meadow-chernozem soil. The experimental plot is located in the southern forest-steppe of Omsk region. Intensive use of irrigated arable land with a rational combination of moisture and mineral nutrition regimes contributes to obtaining maximum yields of forage and grain crops. The creation of various conditions for mineral nutrition due to an increased and high supply of mobile phosphorus and with the application of different options of agricultural technologies made it possible to simulate possible agro-ecological conditions that form contrasting indices of crop productivity. A comparative assessment of the effectiveness of various agricultural approaches to growing crops under irrigation conditions indicates that soil cultivation techniques and forecrops did not significantly affect the content of available phosphorus in the soil. The equilibrium content of mobile phosphorus given a long-term negative balance changed insignificantly. The systematic application of phosphorus-containing fertilizers significantly increased the phosphate status of the soil. However, an adequate assessment of the phosphate status of arable soils is possible using several diagnostic indices (methods). Long-term intensive use of irrigated arable land has reduced the reserves of easily exchangeable potassium from 4 to 1–2 mg/100 g of soil in the arable layer. The content of exchangeable potassium has also decreased by almost 2 times, but the soil remains in a high and very high class of its availability. However, a number of indicators show its increasing depletion in the most mobile fractions of soil potassium. The reserves of non-exchangeable potassium are more stable, which have decreased by about 19% over 40 years, and the soil has passed into the category with an unstable supply.

Investigation of the Process of Purification of Wet-Process Phosphoric Acid and Production of Concentrated Phosphoric Fertilizers Based on it

Fluoride compounds have the most harmful effects on the environment. The main source of fluoride in the soil is phosphorus-containing fertilizers. Purification of wet-process phosphoric acid (WPPA) from fluorine will significantly reduce its content in phosphorous-containing fertilizers and improve the quality of the resulting products. The aim of the study is to reduce the content of fluorine and sulfates in the wet-process phosphoric acid by introducing calcium carbonate, dolomite or phosphorite into the finished extraction pulp before filtration and obtaining high-quality calcium and magnesium-containing phosphate fertilizers based on it. Phosphates were determined by differential photometric, fluorine – ionometric, calcium, magnesium, aluminum, and iron-complexometric, and sulfates-by weight methods. For the first time, scientifically-based data were obtained on the simultaneous reduction of the content of fluorine and sulfates in WPPA from phosphorites of Central Kyzylkum and the production of calcium-magnesium phosphate fertilizers based on it. Optimal technological parameters of the process of simultaneous defluorination and desulfatation of WPPA from Central Kyzylkum phosphorites with calcium carbonate, dolomite and washed burnt phosphoconcentrate (WСPC) were found by introducing them into the second section of the extractor, into the finished extraction pulp in the amount of 100% for sulfate binding and 100-150% for fluorine binding, as well as obtaining high-quality products based on purified WPPA. The degree of transition of fluorine to the gas phase and phosphogypsum at a rate of 100-150% of calcium oxide for fluorine binding is 86.2-89.4% and its content in the wet-process phosphoric acid decreases from 1.18% to 0.22-0.29%. At the same time, the SO3 content in the acid decreases from 1.21% to 0.24-0.26%. The filtration rate of the sulfate-phosphate pulp varies slightly and is 807.6-812.6 kg/m2·h by dry residue.

МЫРЫШ ФИТОҚОСЫЛЫСЫ МЕН МОНОКАЛЬЦИЙ ФОСФАТТАН ФОСФОРЛЫ ТЫҢАЙТҚЫШ АЛУ

In this article the results of synthesis of monocalcium phosphate with a zinc phytocompound are considered. By studying the chemical interaction of monocalcium phosphate with a zinc phytocompound, studying their physicochemical and commercial properties, the optimal compositions of phosphorus fertilizers based on monocalcium phosphate with a zinc phytocompound have been determined. Considering the importance of phosphorus for the formation of plant tissue in increasing the productivity of agricultural crops, the main attention is paid to the assi-milation of phosphorus compounds by plants, which is of paramount importance. It is well known, that one of the main disadvantages of phosphorus fertilizers used in crop production is the low utilization rate of nutritive phosphorus pentoxide, which does not exceed 20-22%. The fact of the low utilization rate of nutritious phosphorus pentoxide in fertilizers is associated with its retrogradation in the soil with the formation of compounds not assimilated by plants. Agrochemical studies have established that phytocompounds increase the utilization rate of phosphorus-containing fertilizers.

Review of characterization, factors, impacts, and solutions of Lake eutrophication: lesson for lake Tana, Ethiopia

Lake eutrophication and water quality deterioration have become a major environmental problem in urban areas and fertilized basins in developing countries across the world. This paper reviews the characterization, driving factors, and impacts of lake eutrophication as well as the mechanism of preventing and recovering lake eutrophication with case studies of eutrophic lakes across the world including Lake Tana, Ethiopia. In most waterbodies including lakes and reservoirs, total phosphorus concentration, chlorophyll a concentration, and Secchi disk visibility in association with species composition are the common criteria to classify lakes and reservoir as oligotrophic, mesotrophic, and eutrophic. Nutrient-rich runoff from cultivated land and industrialized and urbanized cities concentrated in phosphorus are the critical factors that drove eutrophication in water bodies. Among others, controlling external loading of nutrient, ecological, and mechanical methods were found to be common mechanisms to prevent and recover lake eutrophication. Avoiding the factors that are under human control, i.e., a reduction of external loading of nutrients especially targeted on phosphorus reduction into the water basins, relocates sewage, industrial and domestic waste discharges to be lined out of the catchment of the lake. Furthermore, motivating the community to use less phosphorus-containing fertilizers and promoting phosphorus-free detergents are suggested solutions to sustainably prevent and reduce eutrophication in the long run. These could be some possible measures to safeguard endangered Lake Tana of Ethiopia.

ПЛОДОРОДИЕ ОРОШАЕМЫХ ЗЕМЕЛЬ В ЮЖНОЙ ЛЕСОСТЕПИ ОМСКОЙ ОБЛАСТИ

Unsustainable irrigation of chernozems can lead to secondary salinization and other negative consequences. The purpose of the research was to assess the fertility and hydrochemical composition of meadow-chernozem soil of the forest-steppe of Western Siberia under conditions of prolonged irrigation. The surveys were carried out in the fields of the agricultural production cooperative (APC) “Pushkinsky” and Federal State Unitary Enterprise (FSUE) “Omskoye”; cultivation technology – adaptive system of irrigated agriculture. The studies were conducted in 2015–2020 on the Pushkin irrigation system. The object of the research – irrigated meadow-chernozem heavy loamy soil. The methods of route field research and laboratory analyzes were used. The results obtained were compared with the baseline values (1978). With long-term irrigation and intensive agricultural use, the fertility indicators of meadow-chernozem soil did not significantly deteriorate. The arable horizons have a neutral and close to neutral reaction (pH 5.8–6.2), average humus content (5.9–7.2%). The supply of nitrate nitrogen, as a rule, remained at a low and medium level (6.0–14.7 mg/kg) due to the high removal by vegetative crops and the absence of fallow fields in the structure of irrigated arable land. Long-term systematic application of phosphorus-containing fertilizers and creation of a positive P balance led to the improvement of soil phosphate status (99–177 mg/kg). The content of exchangeable potassium remains high (144–353 mg/kg) and is stable over time, which is a feature of chernozems with a heavy particle size distribution. The content of mobile forms of lead, zinc and cadmium does not exceed approximate permissible concentrations in the soil. When analyzing the cation-anionic composition of the water extract of the soil profile of FSUE “Omskoe”, a weak salinity of the chloride type was revealed in the 0.6-1.4 m layer; of the sulfate-chloride type – in the 1.4-1.8 m layer. In the future, it may lead to secondary salinization and serve as a limiting factor for high yields. The absorbing complex of meadow-chernozem soil in the southern forest-steppe is highly saturated with bases. Sodium concentration is minimal; calcium and magnesium cations prevail. The groundwater samples are moderately fresh and of good quality. Among the anions, HCО3- prevails, among the cations – Mg2+ and Ca2+, which indicates the need to control the groundwater level to maintain a favorable ecological state of meadow-chernozem soil.

ОСОБЕННОСТИ ПОТРЕБЛЕНИЯ ОСНОВНЫХ ЭЛЕМЕНТОВ ПИТАНИЯ ЛЬНОМ МАСЛИЧНЫМ В СВЯЗИ С ВНЕСЕНИЕМ УДОБРЕНИЙ

The study of the content and removal of nitrogen, phosphorus and potassium by linseed flax plants of the oilseed variety Severniy showed that more nitrogen and phosphorus accumulated in seeds, and potassium -in straw. The average content levels in seeds were as follow-ing: N -4.79%, P2O5 -0.79%, K2O -1.05% as compared to respective levels in straw: 0.64%, 0.1% and 1.73%. When applying fertilizers, the content of all nutrients in the straw decreases, and in the seeds it mainly remains at the con-trol level. Due to the higher crop yields in all fertilized vari-ants, the removal of phosphorus and potassium exceeds the control; and nitrogen removal –in the variants with a higher rate of nitrogen application. With seeds, an average of 87-87.8% of nitrogen and phosphorus and 37.3% of potassium from the total removal is removed from the field. Increased rate of nitrogen application contributes to greater consumption of not only nitrogen but also phosphorus and potassium. The rates of nitrogen application in the experi-ments do not compensate for its yield removal with seeds; that requires increased nitrogen application against the background of phosphorus-containing fertilizers.

Agroecological efficiency of periodic use of neutralized phosphogypsum in rice crops

The purpose of the experiment was to study the influence of periodic using of neutralized phosphogypsum on the fertility of meadow chernozem soils of Krasnodar Territory, achieving of the appropriate level of rice agrocenosis productivity, and the quality of rice grain. The timing of the effective use of phosphogypsum as a phosphorus fertilizer was revealed during the experiment. It was proved that the same level of mobile phosphorus content in rice soils can be achieved by using either phosphogypsum or standard phosphorus-containing fertilizers. Given the fact that nitrogen and potassium fertilizers are already used, using of phosphogypsum provides an opportunity of getting a 6,34 tons/hectare yield of rice (the same result was achieved using N120P80K60 fertilizer). 3 years after re-fertilizing the soil with phosphogypsum we can notice that effectiveness of phosphogypsum in optimization of rice mineral nutrition program contributes to cost savings of 4155 RUB/hectare in comparison with traditional fertilizing system.

INVESTIGATION OF PHOSPHATE-ION RETENTION STRENGHT IN SOME TYPES OF KAKHETI SOILS

The presented article describes the soil types existing in east Georgia, particularly in several villages of Gurjaani Municipality-Vazisubani, Kalauri, Mukuzani, Shashiani. Meadow-brown and brown soils represent good soil types for viticulture development in Kakheti. The vineyards cultivated on these soils produce such wellknown wines as Tsinandali, Vazisubani, Mukuzani, Akhasheni, Gurjaani, Manavi. The study explores brown carbonate and meadow-brown soil lab tests to examine the absorption of phosphate ions by them. The study showed that the amount of phosphorus deposited through soils is sufficiently absorbed under various conditions, having a positive effect on the amount of crop. Was compared the rates of phosphate absorption in these soils with the efficiency of phosphorus fertilizers, which showed that the higher the absorption of phosphorus, the lower the amount of phosphorus available to the plant and the lower the yield, and the lower the strength of phosphorus retention, the higher the amount of phosphorus to be consumed by the plant and the higher the yield. But under the conditions of high cultivation degree, the strength of phosphorus absorption became weak, resulted in a large amount of exchangeable and movable phosphates already existing in the soil, which is available to the plant. So, the efficacy of phosphorus fertilizers on such soil is weak. The speed of phosphorus absorption in the soil of Gurjaani municipality villages is satisfactory. However, in case of a high degree of cultivation (or in case of excess fertilization), the degree of phosphorus retention decreases. Accordingly, phosphorus-containing fertilizers should be used within strictly controlled limits.

Monitoring the process of bioremediation and revegetation of a phosphogypsum waste stack by remote sensing

Production of phosphorus-containing fertilizers is related with the problem of reclamation of phosphogypsum dumps formed during the processing of Apatite-nepheline ore. In this regard, some attention should be paid to biological remediation as the most effective ecological method. Biological reclamation is one of the ways to protect the environment in the formation of phosphogypsum dumps. In this article, we propose a method for assessing the effectiveness of remediation using phyto monitoring using satellite data, which are used as the results of remote sensing. The proposed method allows estimating the volume and state of biomass of plants forming vegetation cover on the surface of man-made massif.

Investigation of phosphate-ion retention strenght in some types of Kakheti soils

The presented article describes the soil types existing in east Georgia, particularly in several villages of Gurjaani Municipality-Vazisubani, Kalauri, Mukuzani, Shashiani. Meadow-brown and brown soils represent good soil types for viticulture development in Kakheti. The vineyards cultivated on these soils produce such wellknown wines as Tsinandali, Vazisubani, Mukuzani, Akhasheni, Gurjaani, Manavi. The study explores brown carbonate and meadow-brown soil lab tests to examine the absorption of phosphate ions by them. The study showed that the amount of phosphorus deposited through soils is sufficiently absorbed under various conditions, having a positive effect on the amount of crop. Was compared the rates of phosphate absorption in these soils with the efficiency of phosphorus fertilizers, which showed that the higher the absorption of phosphorus, the lower the amount of phosphorus available to the plant and the lower the yield, and the lower the strength of phosphorus retention, the higher the amount of phosphorus to be consumed by the plant and the higher the yield. But under the conditions of high cultivation degree, the strength of phosphorus absorption became weak, resulted in a large amount of exchangeable and movable phosphates already existing in the soil, which is available to the plant. So, the efficacy of phosphorus fertilizers on such soil is weak. The speed of phosphorus absorption in the soil of Gurjaani municipality villages is satisfactory. However, in case of a high degree of cultivation (or in case of excess fertilization), the degree of phosphorus retention decreases. Accordingly, phosphorus-containing fertilizers should be used within strictly controlled limits.