Land area increase in Ukrainian part of the Danube delta

The quantitative indicators of land growth in the Ukrainian part of the Danube delta are considered. Comparison of Landsat satellite images in three key areas of the delta showed that for the period 1975-2020 the area of wetlands at the mouth of the Сhilia channel increased by 1448 hectares due to the accumulation of sediments between the Starostambul and Limba branches and their overgrowth with vegetation. In the area of the Bystroe channel, the area of new lands increased by 1037 hectares due to the artificial deepening of this channel for the Ukrainian ships passage into the Danube River and the deposition of sediments along the coast. A slightly smaller increase in land cover (797 ha) was found in the northern part of the coast of the Ukrainian part of the delta, where saline and carbonate soils are formed. In the future, active land growth is expected in the Musura bay between the mouths of the Starostambul and Sulina branches, ie at the contact of Ukraine and Romania. Some changes in these parameters are expected after a powerful flood in 2021, which will become known after the establishment of a relative equilibrium between the processes of accumulation and erosion after this extreme event.

Quality of winter wheat grain with different systems of main tillage in crop rotations of the Southern Steppe of Ukraine

The article investigates the influence of the application of different systems of basic tillage on the quality of winter wheat grain in short crop rotations of the Southern Steppe of Ukraine. It is established that the grain quality of winter wheat in the Southern Steppe of Ukraine is mainly determined by the genetic characteristics of the variety, but also largely depends on the conditions and technologies of cultivation. In winter wheat grain, which is used for food purposes, reserve proteins are important, which in winter wheat determine the baking properties of flour. In drought conditions, when the yield of winter wheat decreases, the protein content in its grain tends to increase. In wet years, on the contrary, there is a reverse pattern. According to experimental studies, wheat varieties have a negative correlation between grain protein content and yield. It is established that during 2016–2020 research shows almost the same pattern of action of different predecessors and systems of basic tillage on the formation of grain quality of winter wheat in arid conditions. It was found that, on average, according to all variants of research, only with the use of the system of tillage-free tillage received grain of winter wheat with a protein content of 12,5%, which met the requirements of the 2nd class. It is recorded that on average over five years of research on all tillage systems, grain of winter wheat with gluten content was obtained, the quality of which corresponded to the 3rd class. Different tillage systems caused a slight impact on the gluten content, which ranged from 20,6% to 21,1%. It is determined that the precursors have a certain effect on the protein content in the grain of winter wheat. The analysis of qualitative indicators showed that on average in five years of research, when growing winter wheat after a pair of black and a pair of green wheat with winter vetch, grain was formed, which in terms of protein content corresponded to the 2nd quality class. More protein was accumulated in winter wheat grain after a pair of black, which was 12,9%. After peas for grain, as well as a pair of green with a mixture of white mustard and peas, received a grain of winter wheat, which was the 3rd quality class. It was found that on average in five years of research, all variants of winter wheat were grown with gluten content, which met the requirements of the 3rd class. Black vapor and green vapor with winter veneer caused the accumulation of gluten at almost the same level with a small increase in the version with winter vetch up to 21,8%. The lowest level of gluten was obtained in the grain of winter wheat after peas per grain, which was 19,7%. In all variants of the experiment, sidereal steam with winter tillage and the use of tillage-free tillage had the best effect on the growth of winter wheat grain quality indicators. The grain of winter wheat was mainly formed in terms of quality, which allows it to be used for food purposes – mainly in the flour-milling and baking industries, as well as for export. It is established that it is important to further study the quality of winter wheat grain and other cereals in short crop rotations of the arid Southern Steppe of Ukraine, especially in climate change.

To the issue of prospects and problems of organic production of agricultural products in Ukraine

Organizational production of agricultural products is used to preserve the natural environment and to preserve the quality of the products. The development of organic wines in the light of 100 years and over the course of the period has become insane, as for the correct organization of it, you can preserve ecological, social, and commercial transfers. The organizational structure has become a warehouse part of the bio-economy and circular economy, which is a priority for the economic development of the European Union, the USA, Great Britain, the Great Britain, the Republic of Korea, Japan, and the United States of America. For determining the prospects and problems of organic production of agricultural products, general scientific methods were used such as publicity, systematization, analysis, and synthesis, of the scientific literature and normative documents. For an additional analysis of regulatory documents, a procedure for certifying the authorities of the United States, the European Union and Ukraine has been established. Ukraine, in turn, began to take the first steps towards organic production in the late 1990s. It was at this time that she began to grow organic grain and opened export lines for its transportation to other countries, mainly Europe. Ukraine remains a leader in the production and export of organic cereals. Export competitive advantages of national agar products are lower production costs and logistics support. Ukraine continues to increase its organic production capacity - an increasing number of operators are appearing in this sector of agricultural production. As of 2019, the share of organic production of crop products in Ukraine is 1.4% (5th place in the world in terms of growth rate of organic agriculture), which is 467.9 thousand hectares of the total area of agricultural land in 32, 7 million hectares, as well as 470 operators of organic production. The dynamics of changes in organic agricultural production in Ukraine indicates a general trend of increasing their number, but in some periods, there is a decrease due to the economic and political situation in the country and changes in legislation in this area. Ukraine has significant advantages of organic production, which include a high level of soil fertility, favorable climatic conditions, traditional orientation as an agrarian state. Also, the price of Ukrainian products is lower than the minimum price of organic products of European countries. In the organic production of crops use methods that optimize the biological activity of soils, provide a balanced supply of nutrients to plants. At the same time, there are problems in Ukraine that hinder the development of organic production. In particular, the diversity of the territory in terms of the level of pollution of environmental components, lack of practical application of innovations and modern technologies of agricultural production. The lack of state support for organic producers and state certification system (including qualified specialists for its implementation). Resolution of the Cabinet of Ministers of Ukraine of October 21, 2020, № 1032 "On approval of the Procedure for certification of organic production and / or circulation of organic products and amendments to the resolution of the Cabinet of Ministers of Ukraine of October 23, 2019, № 970" approved the stages of certification. Was made the comparison of approaches to the certification of agricultural enterprises in Ukraine shows that they meet European and American standards. However, the absence of a state certification body that certifies organic producers and accredits private certification bodies makes it impossible for state control over organic market operators and the functioning of state certification. The current certification system in Ukraine does not cover the issue of soil contamination or other components of environment, which may affect the quality and safety of organic products. In Ukraine, enterprises in various sectors of the economy use outdated technologies, which can cause soil contamination of agricultural lands, and, accordingly, affect the quality of organic products. Currently, the Laws of Ukraine and the Cabinet of Ministers do not require: the location of the organic agricultural enterprise; content of harmful substances in the soil (including the content of radionuclides and pesticide residues); content in the soil of nutrients that can ensure the production of quality agricultural products and confirm the activities of the farm aimed at maintaining soil fertility. To guarantee the quality of organic products, it is advisable in the certification procedure to consider the level of fertility and soil contamination of agricultural lands, as well as the availability of sources of environmental pollution in the location of the organic producer. Given the above, it is advisable to introduce criteria for assessing the compliance of soils with the requirements of organic production. This approach can guarantee the safety and quality of organic products. During the organization of organic production of agricultural products in Ukraine, the issues of criteria for assessing compliance with regulatory requirements, documentation to be kept by the operator of organic production, etc.

Efficiency of food egg production used for keeping layers of monochrome light with different wavelengths

Artificial light, as an environmental factor, is crucial for the release of hormones that play a key role in a bird's life, growth, immunity and reproduction. For laying hens, light plays an important role in the development and functioning of the reproductive system, significantly affecting the age of laying the first egg, egg-laying and productivity in general. The source of artificial light of the latest generation in poultry farming is LED lamps. Compared to incandescent and fluorescent lamps, LEDs have a longer service life, specific spectrum, lower heat output, higher energy efficiency and reliability, as well as lower maintenance costs, so they are increasingly used by manufacturers. LEDs are a special type of semiconductor diode that can give monochrome light. However, information on the effect of monochrome light with different wavelengths of light on the physiological state of the hens’ body is quite contradictory. Therefore, the aim of the work was to study the efficiency of egg production using monochrome light with different wavelengths. For this purpose, in the conditions of a modern complex for production of food eggs in a poultry house with an area of 2915 m2, 4 groups of hens of the industrial herd "Hy-Line W-36" were formed, each of which was kept in a separate poultry house similar in area and cage equipment. Each poultry house was equipped with cage batteries "Big Dutchman" (Germany), consisting of 1176 cages with an area of 40544 cm2 (362 × 112 cm). The differences between the poultry houses applied only to LED lamps. Thus, hens of the 1st group were kept using LED lamps with a peak light wavelength of 458 nm (blue color of the spectrum), the 2nd group – 603 nm (yellow color of the spectrum), the 3rd group – 632 nm (orange color of the spectrum) and the 4th group – 653 nm (red color of the spectrum). Every day, for 44 weeks of the productive period, the number of eggs laid by the laying hens of each group and the intensity of their laying were determined. The number of hatched hens (due to death and culling) was also counted daily and the number of livestock was determined. Once a week, the weight of eggs and live weight of laying hens were measured from certain labeled cages according to a sample. The European egg production rate on the basis of productivity was determined. It was found that for the maintenance of laying hens of modern white-egg crosses in 12-tier cage batteries of classical designs, it is advisable to use lighting with a peak wavelength of 653 nm, that is with red light. This makes it possible for the 44-week egg-laying period to receive an additional 4.8–18.8 million eggs from each poultry house (0.4–1.6 thousand eggs per 1 m2 of its area) at the highest level of the European egg production rate at 1.0–3.8 units The decrease in the peak wavelength from 653 to 632 nm, which was manifested by a change in light from red to orange, was accompanied by a decrease in the preservation of livestock by 0.7% (3.8% ˂ normal), body weight – by 0.6% within physiological norms, egg-laying per initial laying hen – by 2.9% (5.3% ˂ norm), which caused a decrease in the gross yield of eggs by 4.5 million eggs and egg mass – by 3273 tons from each poultry house, including 1.6 thousand eggs and 112.3 kg per 1 m2 of its area, with a decrease in the level of European egg production rate by 1.0 units. The decrease in the peak wavelength to 603 nm, that is the change in the color of light from red and orange to yellow, was accompanied by a decrease in the preservation of livestock by 6.0–6.7% (9.8% ˂ normal), body weight – by 1.0 –1.7% within the physiological norm, egg-laying per initial laying hen – by 6.6–10.3% (11.6% ˂ of the norm) and feed consumption – by 0.6–0.7% (7.5%) > norms), which led to a decrease in gross egg yield by 7.8–12.6 million eggs and egg mass – by 505.7–833.0 tons from each poultry house, including 2.7–4.3 thousand eggs and 173.5–285.8 kg per 1 m2 of its area, with a decrease in the level of the European egg production rate by 1.6–2.6 units. The decrease in the peak wavelength to 458 nm, that is the change in light color from red, orange and yellow to blue, is accompanied by a decrease in the preservation of livestock by 4.2–10.9% (14.0% ˂ normal), body weight – by 2,3–4.0% (0.2% ˂ of the norm), egg-laying per initial laying hen – by 5.6–15.3% (16.5% ˂ of the norm) and feed costs – by 2.0–2.7 % (5.3%> norms), which led to a decrease in gross egg yield by 6.1–18.8 million eggs and egg mass – by 365.3–1198.3 tons from each poultry house, including 2.1–6.4 thousand eggs and 125.3–288.9 kg per 1 m2 of its area, with a decrease in the level of the European egg production rate by 1.2–3.8 units.

Determination of biological properties of the new synthetic plant growth regulator - spyrocarbon complex with boric acid by means of phytotests

Determining the environmental safety of new synthetic plant growth regulators is an urgent problem. Spirocarbon derivatives were subjected to such determination by means of a specially developed system based on phytotests "germinated seeds". This system allows the values of biometric, cytological and biochemical parameters of the phytotest to determine the toxic, cytotoxic, genotoxic (mutagenic) effects and induction of molecular stress by the synthetic chemical substance being tested. This system was used to establish the biological properties of a new drug - a complex of spirocarbon with boric acid - in relation to five phytotests monocotyledons and dicotyledons plants. Phytotesting was performed in the spectrum of concentrations (10-7-10-2 mol/dm3) of this drug. It demonstrated either the absence or presence of a weak toxic effect on phytotests, which did not exceed 30%. The study showed that the plant growth regulator spirocarbon in combination with boric acid has growthregulating properties, the manifestation of which depends on the concentration of the drug and the species characteristics of plants. Only the maximum concentration (10-2 моль/дм3) of the tested drug is slightly toxic to plants. The obtained results testify to the biological efficiency and ecological safety of the synthesized drug. This allows us to recommend it for use in agricultural practice.

The influence of mineral fertilizers and biopreparation on growth and development of soybean plants

The soybean (Glycine max) is one of the most important food plants of the world, and seems to be growing in importance. It is an annual crop, fairly easy to grow, that produces more protein and oil per unit of land than almost any other crop. It is a versatile food plant that, used in its various forms, is capable of supplying most nutrients. It can substitute for meat and to some extent for milk. It is a crop capable of reducing protein malnutrition. In addition, soybeans are a source of high value animal feed. Nevertheless, the soybean is adapted primarily to the Temperate Zone. Each improved variety has an adaptation determined in large part by latitude. Soybean requires careful home processing to bring out its best qualities, and if not well prepared, it has an off-flavor that is seldom appreciated Soybeans need to be inoculated with a particular strain of Rhizobium fungus before planting. This fungus fixes nitrogen (i. e. takes elemental nitrogen from the air and adds it to the soil in a form that the soybean plant can use). However, if soybeans are planted in a field that contained soybeans as a previous crop, they may not require inoculation because the Rhizobium will still be in the soil. If soybeans are not grown in association with Rhizobium, they will grow more slowly, require nitrogen fertilizer, and yield less. Rhizobium inoculum must be fresh (viable) and is usually purchased with the seed. If Rhizobium inoculum is not available in a particular area, and soybeans are not now being grown, it may be difficult to produce this crop. Soybeans need fertilizer, including both the macronutrients phosphorous and potassium (P and K) and sometimes micronutrients. Nitrogen is not required if soybeans are properly inoculated. Soybeans need rather large amounts of phosphorous, calcium, magnesium, and sulfur. Minor elements are sometimes required. Soybeans cannot be recommended for unfertilized soils. For optimum soybean yield, it is necessary to use both biological N2-fixation and nitrogen uptake by soybean roots. Nitrogen fertilizer applied to soybean is based on the plant nitrogen needs during seedling development prior to nodule formation that is crucial to the growth and development of soybean As with all crops, soybean yield is the result of the net accumulation of organic compounds assimilated through photosynthesis. Research on soybean photosynthesis conducted during the 1950’s and 1960’s found that several cultivars grown at that time became light saturated. However, much of those data were collected from plants grown in a greenhouse or other artificial environment. Much of the information on the response of soybean photosynthesis to changing light levels however is dated, having been published prior to 1985, with cultivars that are no longer in production, using less portable and sophisticated instrumentation than is now available. In the article are presented results of researching peculiarities of growth development and formation of soybean photosynthetic productivity depending on weather conditions, level of mineral fertilization and different application methods of biological product on the chelate form under conditions of the Right-bank Forest-Steppe. It is established that a systematic approach to soybean nutrition, namely its cultivation on the background of optimal doses of mineral fertilizers N30P45K45 and the use of biological product Organic-Balance for seed treatment in combination with foliar feeding creates the best conditions for growth, development and preservation of maximum plants full ripeness, which is the basis for obtaining high grain yields.

Main features of reforming the coasts of Kaniv reservoir

Reservoirs provide an electricity generation, promote the development of water transport, municipal and industrial water supply, irrigation, fisheries, recreation and other economic and social needs. However, calls are increasingly being made to limit the creation of new artificial reservoirs and even to destroy existing ones. The reason for this is the significant and very real negative environmental consequences of their creation and functioning – flooding of large areas of valuable land in river valleys, relocation of large numbers of people to new areas, flooding of low and erosion of high banks of reservoirs, deterioration of river water quality due to stagnation and "blooming” and many others. The aim of this work is to analyze the peculiarities of reforming the shores of the Kaniv Reservoir under the impact of hydrological and morphological processes, measures for the coast protection from erosion, deepening the channel and alluvium of new lands by dredging (mainly in the upper part of the reservoir) are considered. The study of this problem in the reservoirs of the Dnieper cascade, including Kaniv, we started from 1993-1997. Therefore, research methods have changed significantly at different stages. Standard methods of soil science were used to study the impact of the reservoir on the coastal soils, primarily on flooding, waterlogging and soil erosion. Since 2010, more detailed terresrial and water expeditionary routes (land) studies have been started to study the overgrowth of the reservoir with hydrophytic and hygrophytic vegetation with the formation of hydromorphic soils on the islands of the reservoir and its coast. Remote sensing methods of the Earth for analyzing the series of space images Landsat-2, 4-5, 7 and 8 were used to study the temporal and spatial changes of landscapes, as well as geospatial positioning of observation points by GARMIN GPS receiver. The important role of the dams construction and pumping stations to protect the low shores of the reservoir from flooding was noted, which, however, created significant problems in the operation of the facility due to rising electricity prices. Attention is paid to the ecological consequences of the new alluvial lands development within the reservoir water area, in particular to “blooming” and deterioration of water quality, as well as to the limitation of the ability to pass extreme floods and the threat of adjacent territories submergence. The nature of erosion and abrasion of the high right bank was studied with the use of a quadcopter, mainly in the area from the village of Rzhishchiv to the village of Trakhtemiriv. The role of marl clays in weakening the abrasion of shores is emphasized and their vulnerability to destruction is shown. The role and development of ravines on the coast and their participation in the fragmentary formation of hydromorphic landscapes along steep cliffs are noted. On the low left bank there is a reformation of the shores in the area from the village of Kyiliv to the Rzhyshchiv military range, where large areas are set aside for fisheries, hunting and recreational activities, as a result of which the wetlands are reduced. The uncertainty of the problem of pumping the water of the Trubizh River into the reservoir to protect the floodplain lands from submergence is emphasized. It is not recommended to use “Raketa” ships for water transport in this reservoir due to their negative impact on shoreline abrasion.

Biotesting of polymeric waste excluded from solid waste waste

Introduction. Annually, the volume of accumulated polymers in landfills in Ukraine is growing by more than 1 million tons, but the volume of recycled polymer packaging over the past ten years has not exceeded 3%. The goal is to establish the degree of toxicological impact on biosphere objects of polymers extracted from solid waste, to assess the safety of using household polymer waste as a secondary raw material for further processing. The task is to establish the degree of biological and toxicological safety of polymer wastes extracted from solid waste. Methods and techniques: toxicological - determination of water toxicity on acute Daphnia magna according to DSTU 4173: 2003 (ISO 6341: 1996, MOD) and chronic according to DSTU 4166: 2003 (ISO 10706: 2000, MOD), and Paramecium caudatum ciliates, soil microflora reactions (saprotrophic soil bacteria CFU / g) according to MR 2609-82, the assessment of phytotoxic effects on higher plants was carried out by vegetation methods according to ISO 17402-2008, ISO 17126-2005a, ISO 22030: 2005b, ISO 11269 -1:2012a. Results. The research results show that aqueous extracts from waste polymers extracted from solid waste and their mixture do not have a pronounced toxic effect on aquatic organisms. There is no significant effect on soil bacteria. The study of the effect of polymer waste on seed germination did not reveal phytotoxic effects for any crop. A slight phytotoxic effect was observed during the study of PVC and PS waste. Wheat and mustard were the most sensitive. The level of phytotoxic effect was within acceptable limits and did not exceed 5.67%. Evaluation of phytotoxic effects on stem length showed the presence of effects from all processed products except PVC. The impact, characterized as weak, ranged from - 2.06% (PP) to - 13.27% (PS). The effect on root length was found for samples with PS waste (-7.23%), which was characterized as weak and PVC (-43.52%) - medium. Watercress and mustard were the most sensitive plants to the effects of polymer waste. Conclusions. The studied samples of polymer waste do not show hygienically significant toxic effects on water and soil test objects, even in concentrations of 1: 1, so the impact on the above test organisms polymer waste removed from solid waste is classified as hazard class 4. According to the assessment of phytotoxic effect, polymer waste removed from solid waste is classified as hazard class 4, except for PVC - hazard class 3.

Influence of growth regulators on yield of carrot tablets in the conditions of the forest-steppe of right-bank Ukraine

In the results conducted between studies, the studied regulators affect the biometrics and yield of table carrot plants. The greatest influence on the interphase period "root formation - technical maturity" was performed by the regulator Phytocid-r, which helped reduce the growth of the interphase period Shantane KL by 3 days, in the hybrid Brilliance F1 by 4 days. With the use of the growth regulator Phytocid-r of the vegetation period of the population in the variety Shantane KL – 117 days, in the hybrid Brilliance F1 – 118 days, respectively 6 and 7 days shorter with control. The highest weight of root crops during the growing season was observed using the growth regulator Phytocid-p, in the variety Shantane KL the increase relative to control was 15.5 – 23.7 g, in the hybrid Brilliance F1 – 18.5 and 25.5 g. root crops were also characterized by variants using growth regulators Ivin and Emistym C, where the increase relative to the control at the end of the growing season was: in the variety Shantane KL – 4.1-8.3 g, in the hybrid Brilliance F1 – 4.9 and 6.0 g respectively. The growing season of table carrots was characterized by slightly higher temperatures and low rainfall, with a long dry period, which negatively affected the formation of roots of table carrots. However, the highest yield was obtained from the option using the growth regulator Phytocid-p, which provided an increase in yield at the level: in the variety Shantane KL – 8.5 t / ha, in the hybrid Brilliance F1 – 13.3 t / ha. The highest percentage of marketable yield was obtained using the growth regulator Phytocid-p in both varieties and hybrids – 94.8 and 95.2 %, which is more than the control by 11.2 and 11.0 %. The largest mass of root crop was formed by plants using the growth regulator Phytocid-r: in the variety Shantane KL – 112 g, in the hybrid Brilliance F1 – 118 g, which is 23.8 and 25.6 g more than the control. The diameter of the root was in the range of 5.8-7.0 cm and varied slightly from the growth regulator. The hybrid Brilliance F1 was characterized by a longer root length. However, taking into account the applied growth regulator, it was found that the highest figure was for the use of Phytocid-r: in the variety Shantane KL – 17.6 cm, in the hybrid Brilliance F1 – 18.3 cm, which is more than the option without treatment 1.2 and 1.0 cm.

Ecological assessment of the toxicity of nitrogen compounds for aquatic organisms using the Lemna minor L. Biotest

This research is motivated because of increasing eutrophication problems in water bodies. This happens as a result of excess nitrogen and phosphorus. Too many of these nutrients can cause algae to grow, leading to blooms. Harmful algal blooms consume dissolved oxygen in water. As a result, the oxygen level decreases, affecting the aquatic ecosystem. The stenobiont plant, which belongs to the group of the most sensitive bioassays, is the small duckweed Lemna minor L. This plant is sensitive to increasing levels of nutrients and blooms of algae. This research aimed to determine the level of water toxicity using the bioassay of duckweed (Lemna minor L.) to establish dangerous concentrations of nitrogen compounds (NO2-, NO3-, NH4+) (CA) for higher plants of aquatic ecosystems with subsequent risk forecast for Dnipro basin. The research was carried out in accordance with DSTU 32426-2013 “Testing of chemicals of environmental hazard. Lemna sp. Growth Inhibition. Test”. The number of effects associated with nitrogen compounds (NO2-, NO3-, NH4+) on plant growth and development during the testing period was detected. The number of green layers is the main variable that was investigated in the experiment. Changes in the morphological features of duckweed were also studied, in accordance with the standard, the toxicity of water was assessed by changes in leaf colour, manifestations of chlorosis, the transformation of whole plants into individuals, the appearance of young leaves. To estimate the number of effects associated with the nitrogen compounds toxicity, the half-maximal effect (EC50) was studied. It should be noted that studies of water toxicity on NO2- content using the Lemna minor L. test showed that even at the lowest concentration of 0.1 mgNO2-/L aquatic biota will be significantly affected by the toxicity with possible subsequent death. Summarizing the results of the research of the Lemna minor L reaction to the toxicity of water with different concentrations of NO3- came to the conclusion that even the lowest concentration (0.1 mgNO3-/L) will have a negative impact on their growth and development of the plant. Generally, 40.0 mgNO3-/L is considered “safe” for fish farming. However, this is not a case for aquatic vegetation, as shown by this result – such concentration will be toxic and cause death. If we take into account NH4+ salts, the reaction was even more progressive, the deterioration of the leaf layers of duckweed began to occur immediately from the first days of the research, and the number of damaged duckweed was 30% more on day 24 than in salts NO3-, NO2-. For algae of aquatic ecosystems the highest level of toxicity is shown by nitrogen compounds in the form of NO3-, the median concentration of EC50 (96 hours) is 7.7 mg/L. Therefore, the regulation of pollution of aquatic ecosystems by nitrogen compounds should be based primarily on the content of NO3-. To avoid the negative effects of compounds such as NH4+ and NO2- it is necessary to take into account their toxicity level: EC50 (96 hours) NH4+ – 250 mg/L, EC50 (96 hours) NO2- – 720 mg/L. From the above, the free-floating hydrophyte Lemna minor L. is a promising object of testing, as it easily absorbs all the elements and quickly shows the result. It is able to quickly accumulate harmful substances, because in the process of life, its leaves absorb absolutely all the elements that fall into the water.