Mineral Forms Of Nitrogen Research Articles

Selected Carbon and Nitrogen Compounds in a Maize Agroecosystem under the Use of Nitrogen Mineral Fertilizer, Farmyard Manure, Urease, and Nitrification Inhibitors

Carbon and nitrogen compounds in agroecosystems have attracted much attention in recent years due to their key roles in crop production and their impacts on environment quality and/or climate change. Since fertilization profoundly disrupted the C and N cycles, several mitigation and/or adaptation strategies, including the application of farmyard manure (FYM) and/or urease and nitrification inhibitors (UI and NI), have been developed. The aim of this study was to evaluate the contents of soil organic carbon and its fractions, the total and mineral forms of nitrogen, as well as CO2 and N2O emissions under mineral and organic fertilization with and without urease and nitrification inhibitors in a maize agroecosystem. A two-year field study was carried out on Cambisols (silt) in Poland. The experiment scheme included nine treatments: C (the control without fertilization), UAN (Urea Ammonium Nitrate), UAN+UI, UAN+NI, UAN+UI+NI, FYM with N mineral fertilizer base, FYM with N mineral fertilizer base+UI, FYM with N mineral fertilizer base+NI, and FYM with N mineral fertilizer base+UI+NI. It was found that treatments fertilized with cattle FYM were higher sinks and sources of C and N compounds in comparison to the UAN plots. The organic carbon, humic and humin acid, and total nitrogen concentrations, in contrast to ammonium and nitrate nitrogen, were not affected by the inhibitors added. Nitrification and urease inhibitors were effective in decreasing N2O emissions only in treatments that were exclusively applied with UAN and had no significant influence on CO2 emissions.

СОЕДИНЕНИЯ АЗОТА И ФОСФОРА В ВОДНЫХ ОБЪЕКТАХ КАЗАХСТАНСКОЙ ЧАСТИ БАССЕЙНА Р. ИРТЫШ

We present materials from our research to study the distribution of various forms of mineral nitrogen and phosphorus in the Irtysh River basin in the summer of 2023. It has been established that the content of mineral forms of nitrogen and their ratios are not the same in the water of rivers and lakes. In the water of the river’s tributaries. The Irtysh River was dominated by nitrate ions (from 0.039 to 1.033 mgN/dm3), with a maximum in the right-bank tributaries. The nitrite and ammonium ions share accounted for 2.7, 32.7 and 15.3, 38.3% of the total nitrogen, respectively. The share of nitrates in the Black Irtysh River averaged 59% of the amount of nitrogen. Downstream, within the Pavlodar region, nitrates were more often absent, and the proportion of ammonium nitrogen increased. Mineral soluble phosphorus (phosphate ions) was found in the water of all surveyed areas of the basin in insignificant concentrations (0.015 – 0.130 mg/dm3) due to the low solubility of its compounds and intensive absorption by hydrobionts. From the upper to the lower sections of the Irtysh there was a slight increase in the concentration of nitrogen and phosphorus compounds, as a result of the influence of the anthropogenic factor.

Гидробиоценозы озера Малое Янисъярви (Южная Карелия) в условиях товарного выращивания форели

Based on our own and literature data, the state of the ecosystem of Lake Maloe Yanisjarvi (South Karelia) in the conditions of industrial trout farming (since 2020) has been analyzed. The reservoir belongs to the mineralized (24.4-31.6 mg/l), calcium sulfate class. The chemical composition of the waters is not subject to significant fluctuations throughout the year. Among the forms of mineral nitrogen, nitrate and ammonium predominate (the maximum concentration noted is 0.12 mg/l). The total phosphorus content does not exceed 0.012 mg/l, mineral – 0.01 mg/l. Fluctuations in the concentration of dissolved oxygen are in the range of 7.0-9.1 mg/l. High flow rate (indicator of conditional water exchange 3.5 year-1) is the main stabilizing factor contributing to the preservation of the hydrochemical regime of the reservoir. In general, the water masses of Lake Maloe Yanisjarvi in their chemical composition meet the requirements for the aquatic environment in the cage cultivation of salmon. The data on the main hydrological and hydrobiological indicators of the lake are presented. According to the level of quantitative development of zooplankton in the summer-autumn period, the lake corresponds to the oligotrophic type with a biomass of up to 1 g/m3, benthos – to the α-mesotrophic type (2.8 g/m2). The reservoir belongs to the highest fishery category, according to literature data, valuable fish species (salmon, trout, whitefish and grouse) are noted as part of the ichthyofauna. Recommendations on the timing of the ecological expertise of the lake are given.

Оценка на зеолит и диатомит за оптимизиране на хранителния режим при два типа почви

The research investigates the effectiveness of natural zeolites, diatomaceous earth and compost mixture as self-effects and their combinations on the NPK potential of two soil types. In both soils, the following variants were investigated: soil-compost (SC), soil-zeolite (SZ) and soil-diatomite (SD); as well as combined variants such as soil-compost-zeolite (SCZ) and soil-compost-diatomite (SCD). These components are composted over 60 days under controlled conditions. To achieve this goal, basic physicochemical parameters such as pH and electrical conductivity, cation exchange capacity (CEC), and agrochemical indicators – humus and mineral forms of nitrogen, phosphorus and potassium – before and after composting were traced. The study shows that combining natural zeolites and diatomaceous earth sludge with compost contributes to increasing potassium and phosphorus levels in the soil while maintaining the stability of soil organic matter, highlighting the most effective impact on phosphorus under certain pH conditions.

Microalgae Production on Biogas Digestate in Sub-Alpine Region of Europe—Development of Simple Management Decision Support Tool

In a one-and-a-half-year study conducted in the ALS6 region in Europe (Ljubljana, Slovenia), the cultivation of microalgae in anaerobic digestate from food waste, mainly Scenedesmus dimorphus and Scenedesmus quadricauda, was investigated in three ponds (1260 L each) under a greenhouse. The effects of changing digestate quality and quantity as well as seasonal fluctuations on the productivity of the microalgae were investigated in three stages: Learning/Design (SI), Testing (SII), and Verification/Calibration (SIII). A decision support tool (DST) was developed using easy-to-measure parameters such as pH, temperature, electrical conductivity, mineral nitrogen forms and physical, biological parameters (OD, delayed fluorescence intensity). To control optimal pond operation, we proposed the photosynthetic culture index (PCI) as an early indicator for necessary interventions. Flocculation and nitrite levels (above 3 mg NO2-N L−1) were signals for the immediate remediation of the algae culture. Under optimal conditions in summer SIII, an average algal biomass production of 11 ± 1.5 g m−2 day−1 and a nitrogen use efficiency of 28 ± 2.6 g biomass/g N-input were achieved with the developed DST. The developed DST tool was, in this study, successfully implemented and used for the cultivation of microalgae consortia predominated by Scenedesmus dimorphus and S. quadricauda with biogas digestate. DST offers the possibility to be modified according to producers’ specific needs, facility, digestate and climate conditions, and as such, could be used for different microalgae cultivation processes with biogas digestate as a food source.

Effect of Microbial Preparation and Biomass Incorporation on Soil Biological and Chemical Properties

In order to meet the global nutritional needs of a growing population, attempts are being made to develop strategies that can effectively offset the negative effects of intensive farming. The aim of this study was to investigate the effect of Effective Microorganisms (EM) preparation and organic matter incorporation on the soil microbiological and chemical features. The analyses included the number of heterotrophic bacteria, fungi, actinobacteria, cellulolytic, amylolytic and proteolytic microorganisms, and bacteria of the genus Azotobacter. The content of organic carbon, the total and mineral nitrogen forms of phosphorus, potassium, magnesium, and the pH were also determined. The application of an EM of higher dose combined with the manure and straw resulted in the highest abundance of heterotrophic bacteria (165.1 × 106 cfu g−1), actinobacteria (43.2 × 105 cfu g−1), cellulolytic (17.2 × 106 cfu g−1), and proteolytic bacteria (82.0 × 106 cfu g−1). The highest content of chemical parameters was always observed in the experimental variant, including biomass incorporation, accompanied by EM use. The novelty of our research is the analysis of the synergistic effect of the experimental factors studied on the microbiological and chemical parameters of arable soils.

Dynamics of Organic Nitrogen Compound Mineralization in Organic Soils under Grassland, and the Mineral N Concentration in Groundwater (A Case Study of the Mazurian Lake District, Poland)

Peatlands serve numerous functions, with one of the main ones being the retention of nutrients, including mineral nitrogen. A field study in organic soils was carried out in the Mazurian Lake District situated in north-eastern Poland (53°37′50′ N, 20°28′51′ E). In the test peat soils, the rate of organic nitrogen compound mineralization varied significantly depending on the season. The dynamics of the organic matter mineralization process were most strongly influenced by the soil use and the season. The mineral N release was higher in organic soil under intensively used grassland. In this soil, much more mineral nitrogen was released during the summer and spring periods. The dominant form in the organic nitrogen compound mineralization processes was N-NO3. The highest dynamics of the organic nitrogen compound mineralization were noted at a soil moisture content ranging from 57% to 59%. The interdependence of the soil moisture content and the rate of organic nitrogen compound mineralization fluctuated over the study period, with an increase in spring and a decrease in summer. A correlation was demonstrated between the nitrate form content in the peat soils under intensive cultivation and the nitrate-nitrogen concentration in groundwater, while no correlation was demonstrated between the N-NO3 content in the soils under a forest and the N-NO3 concentration in the groundwater of these soils. The results provide the basis for the conclusion that the land use type (forest, grassland), which determines the morphological structure of organic soils, affects the intensity of the infiltration of different mineral nitrogen forms.

EFFICIENCY OF ZEOLITE AND ZEOLITE ENRICHED WITH AMINO ACIDS AS FERTILIZERS FOR MILLET

The purpose of the work is to study the effect of zeolite siliceous rock and fertilizer based on it, enriched with amino acids, on agrophysical, biological, agrochemical properties of leached black soil and millet yield. The research was carried out on the experimental field of Ulyanovsk State Agrarian University named after P.A. Stolypin. The materials (objects) were zeolite from Yushanskoye deposit in Ulyanovsk region; zeolite enriched with amino acids; Saratovskoye 12 common millet. The scheme of the experiment included 4 variants: 1 - control, 2 - zeolite 500 kg/ha, 3 - zeolite enriched with amino acids, 500 kg/ha, 4 - N40P40K40. The area of the record plot was 20 m2 (2*10), fourfold repetition. The soil of the experimental field is leached black soil with low humus content (3.8-4.0%), high mobile phosphorus content (150 mg/kg by Chirikov), increased content of exchangeable potassium (89 mg/kg), a slightly acidic reaction of soil solution (pHKCl of 5.5 units). The experiments were carried out with strict adherence to all methodological requirements, analyzes were conducted according to relevant state standards. It was established that zeolite of Yushansky deposit of Ulyanovsk region and fertilizer based on it, enriched with amino acids, have a positive effect on leached black soil properties: agrophysical state of the arable layer improved (the content of agronomically valuable aggregates increased by 11.4-11.5%); overall biological activity increased (by 15-32%); the content of phosphorus available to plants increased by 27-38 mg/kg, potassium by 11-12 mg/kg, mineral forms of nitrogen by 13.1 and 8.9 mg/kg, silicon by 10.7 and 10.9 mg/kg of soil. The increase of millet grain yield in case of application of pure zeolite was 0.40 t/ha (16%), in case of zeolite enriched with amino acids - 0.93 t/ha (37%). The yield of millet in the variant with application of zeolite enriched with amino acids was not worse than in the variant with mineral fertilizers.

Loss of Nutrients Through Soil Water Erosion in Calcic Chernozem

Abstract The application of technology for water erosion control plays an essential role in development of sustainable agricultural systems. The paper presented observes the study results from a period of six years in terms of losses of mineral nitrogen and available forms of phosphorus and potassium in the cultivation of wheat and maize on sloping terrains (on calcic chernozem soil type) under the influence of water erosion processes. The impacts of four different types of technology (conventional technology performed along the slope; conventional technology applied across the slope; surface mulching; and minimum tillage with vertical mulching) on nutrient losses were tested. On average, the annual losses of mineral nitrogen, available forms of phosphorus and potassium in wheat production along the slope utilizing conventional technology were 6.0 kg·ha−1y−1, 1.6 kg·ha−1y−1, 5.9 kg·ha−1y−1, and 11.3 kg·ha−1y−1, 2.1 kg kg·ha−1y−1, 10.8 kg kg·ha−1y−1 in maize production. The lowest losses in these elements occurred with minimal employment of tillage system, as they reached values of 2.3 kg·ha−1y−1; 0.6 kg·ha−1y−1, 2.0 kg·ha−1y−1, respectively, in wheat production, and 1.7 kg·ha−1y−1, 0.3 kg·ha−1y−1, 1. kg·ha−1y−1, respectively, in maize production.

The Stochastic Assembly of Nitrobacter winogradskyi-Selected Microbiomes with Heterotrophs from Sewage Sludge or Grassland Soil.

Chemolitho-autotrophic microorganisms like the nitrite-oxidizing Nitrobacter winogradskyi create an environment for heterotrophic microorganisms that profit from the production of organic compounds. It was hypothesized that the assembly of a community of heterotrophic microorganisms around N. winogradskyi depends on the ecosystem from which the heterotrophs are picked. To test this hypothesis, pure cultures of N. winogradskyi were grown in continuously nitrite-fed bioreactors in a mineral medium free of added organic carbon that had been inoculated with diluted sewage sludge or with a suspension from a grassland soil. Samples for chemical and 16S rRNA gene amplicon analyses were taken after each volume change in the bioreactor. At the end of the enrichment runs, samples for shotgun metagenomics were also collected. Already after two volume changes, the transformations in community structure became less dynamic. The enrichment of heterotrophs from both sewage and soil was highly stochastic and yielded different dominant genera in most of the enrichment runs that were independent of the origin of the inoculum. Hence, the hypothesis had to be refuted. Notwithstanding the large variation in taxonomic community structure among the enrichments, the functional compositions of the communities were statistically not different between soil- and sludge-based enrichments. IMPORTANCE In the process of aerobic nitrification, nitrite-oxidizing bacteria together with ammonia-oxidizing microorganisms convert mineral nitrogen from its most reduced appearance, i.e., ammonium, into its most oxidized form, i.e., nitrate. Because the form of mineral nitrogen has large environmental implications, nitrite-oxidizing bacteria such as Nitrobacter winogradskyi play a central role in the global biogeochemical nitrogen cycle. In addition to this central role, the autotrophic nitrite-oxidizing bacteria also play a fundamental role in the global carbon cycle. They form the basis of heterotrophic food webs, in which the assimilated carbon is recycled. Little is known about the heterotrophic microorganisms that participate in these food webs, let alone their assembly in different ecosystems. This study showed that the assembly of microbial food webs by N. winogradskyi was a highly stochastic process and independent of the origin of the heterotrophic microorganisms, but the functional characteristics of the different food webs were similar.

Microbiota of the rhizosphere zone of Calamagrostis epigeios from a coal mine waste dump

The microbiota plays an important role in the processes of plant overgrowth of coal mine waste dumps, enabling the transformation of numerous compounds into forms available to plants. The overgrowth of coal mine dumps is influenced by many factors. Pioneers are plant species that have a wide ecological and phytocenotic amplitude. Calamagrostis epigeios (L.) Roth. occupies a special place among them. The composition of the microbiota of the rhizosphere zone of C. epigeios was studied in relation to the age of the plants and the stage of the succession of the “Vizeyska” mine dump (Ukraine). It was established and confirmed as a result of two-factor variance analysis that the growth phase of C. epigeios and the stage of the succession of coal mine waste dumps have different effects on the number of microorganisms from the rhizosphere zone of plants. The number of pedotrophic microorganisms, microorganisms that metabolize nitrogen of organic compounds, cellulose-degrading microorganisms, and microscopic fungi depended more on the age of C. epigeios, and not on the stage of the succession of the studied area. The number of chemolithotrophic bacteria, particularly thiobacteria, decreased with the change of the growth phase of C. epigeios. The number of acidophobic thiobacteria depended more on the stage of succession, and the number of acidophilic thiobacteria depended more on the age of the C. epigeios. The number of microorganisms that metabolize nitrogen of organic compounds, oligonitrophilic microorganisms and microorganisms that metabolize nitrogen of inorganic compounds in the samples of tailings from the area with grasses and perennials and from the area with grasses, shrubs, and sun-loving trees was higher, compared to the number of these groups of microorganisms in the control and changed with the change in the growth phase of C. epigeios. The number of microorganisms that metabolize nitrogen of organic compounds, oligonitrophilic microrganisms and microorganisms that metabolize nitrogen of inorganic compounds was the highest in the samples from the area with grasses, shrubs, and sun-loving trees during the adult growth phase of C. epigeios. In the area where C. epigeios dominated within the vegetation, the highest number of microorganisms that metabolize nitrogen of organic compounds was also during the adult phase of C. epigeios, and the number of bacteria that assimilate mineral forms of nitrogen and oligonitrophilic microorganisms was the highest during the sub-adult stage. The index of pedotrophicity is higher in the samples taken in the area where C. epigeios prevails among other herbaceous plants, and where in the tree layer there are Betula pendula, Populus tremula with an admixture of Pinus sylvestris. Pedotrophicity indices which were calculated for these samples do not depend on the growth stage of C. epigeios and are higher than for the control area. Immobilization-mobilization of nitrogen indices in samples of tailings from the area with grasses and perennials and from the area with grasses, shrubs, and sun-loving trees ranged from 1.94 to 3.52 and were higher compared to the control site.

Biotechnologies used to deal with recycling of grape pomace

The article presents experimental data on the chemical composition of grape pomace subject to the used grape processing technology. Grape pomace is shown to contain a rich complex of biologically valuable compounds, including polyphenols (with antioxidant activity), polysaccharides (including pectin substances), and nitrogenous substances which serve as the substrate for fermentative catalysis and development of microorganisms. It has been established that the microorganisms of Baikal EM-1 preparation most actively developed on sweet pomace of white and red grape varieties. When Baikal EM-1 was inoculated onto the pomace surface, the number of microorganisms using mineral forms of nitrogen grew substantially, and the number of free amino acids triples. It was fungi of Trichoderma and Rhisopus genera that were developing most actively on all types of grape pomace, including that of red grapes. The effect of the fungi was accompanied by a fast change in the structure of the pomace – viz., appearance of the liquid and slimy phases. An active complex of enzymes of cellulolytic and hemicellulasic activity was shown to ensure a deeper level of maceration of the vegetative tissue of pomace, enabling to perfect its processing technology.

Liming and grazing intensities effects on soil mineral nitrogen throughout the pasture cycle in a subtropical integrated crop-livestock system

Grazing intensity is a preponderant factor for the success of integrated crop-livestock systems (ICLS). Management of grazing intensity impacts soil organic matter (SOM) dynamics, soil reacidification process, and amount and quality of residues added to the ICLS. Consequently, the soil mineral nitrogen (N) forms may present different behavior throughout the pasture cycle, because they are directed linked to SOM and soil acidity dynamics. This study aimed to evaluate the impact of grazing intensities and liming in the temporal variation [...]

Nitrification, denitrification, and competition for soil N: Evaluation of two Earth System Models against observations.

Earth System Models (ESMs) have implemented nitrogen (N) cycles to account for N limitation on terrestrial carbon uptake. However, representing inputs, losses, and recycling of N in ESMs is challenging. Here, we use global rates and ratios of key soil N fluxes, including nitrification, denitrification, mineralization, leaching, immobilization, and plant uptake (both NH4 + and NO3 - ), from the literature to evaluate the N cycles in the land model components of two ESMs. The two land models evaluated here, E3SM Land Model version 1 (ELMv1)-ECA and CLM5.0, originated from a common model but have diverged in their representation of plant-microbe competition for soil N. The models predict similar global rates of gross primary productivity (GPP) but have approximately two-fold to three-fold differences in their underlying global mineralization, immobilization, plant N uptake, nitrification, and denitrification fluxes. Both models dramatically underestimate the immobilization of NO3 - by soil bacteria compared with literature values and predict dominance of plant uptake by a single form of mineral nitrogen (NO3 - for ELM, with regional exceptions, and NH4 + for CLM5.0). CLM5.0 strongly underestimates the global ratio of gross nitrification:gross mineralization and both models are likely to substantially underestimate the ratio of nitrification:denitrification. Few experimental data exist to evaluate this last ratio, in part because nitrification and denitrification are quantified using different techniques and because denitrification fluxes are difficult to measure at all. More observational constraints on soil nitrogen fluxes such as nitrification and denitrification, as well as greater scrutiny of the functional impact of introducing separate NH4 + and NO3 - pools into ESMs, could help to improve confidence in present and future simulations of N limitation on the carbon cycle.

Microbiological assessment of sod-medium podzolic soil using various elements of biologisation

To assess the ability of soils to self-repair and self-rehabilitation, it is important to monitor the indicators of soil microbiological activity. In conditions of manure deficiency, the restoration of organic matter of soils is provided by using non-commercial share of the crop and growing green manure crops, which is especially important for zonal soils of Ukrainian Polissia. The purpose of the study was to estimate the number of various physiological groups of microorganisms in sod-medium podzolic soil under the influence of various fertiliser systems. Field, laboratory, and statistical methods were used in the study. Field method: an experiment was conducted in a field of the Chernihiv Institute of Agricultural Microbiology and Agroindustrial Production of the NAAS with an area of sown plots of 102 m2 on sod-medium podzolic light loamy soil with a humus content of 0.9-1.1% in 0-30 cm layer. The number of different groups of microorganisms that transform carbon and nitrogen compounds was determined in soil samples. Statistical methods – system analysis, mathematical and statistical analysis. Sowing of green manure such as lupine and oilseed radish had a positive effect on the number of ammonifiers (4.3-13.2 million CFU), which is 44-180% more than in the control. The mineral fertiliser system for potatoes also increased the number of ammonifiers by 15-50% compared to the option without fertilisers. The mineralisation-immobilisation coefficient was calculated as the ratio of the number of microorganisms that immobilise mineral forms of nitrogen to the number of organotrophs, and the pedotrophicity coefficient by the ratio of the number of microorganisms on soil agar to the number of microorganisms that grew on meat-peptone agar. It was established that the cultivation of green manure on sod-podzolic soil has a positive effect on the development of physiological groups of microorganisms and the microbiological processes tend to accumulate humus. The materials of the study are of practical value for agricultural producers who are engaged in growing potatoes on sod-podzolic soils in the possibility of replacing manure and mineral fertilisers in the fertiliser system of agricultural crops with green manure (lupine, oilseed radish)

Assessment of the Potential of Umbrella Thorn [Vachellia tortilis (Forssk.) Galasso & Banfi] for the Rehabilitation of Sub-Sahelian Mining Sites at Essakane, North-Eastern Burkina Faso

Establishment of plant communities at mine sites with significant disturbance depends upon factors such as the presence of efficient mycorrhizal fungi and rhizobia. Field and greenhouse experiments were conducted to assess growth performance of umbrella thorn as a potential tree species for reforestation of mine sites in arid areas. In the first experiment, seedlings were transplanted onto waste rock stockpile (WR) and tailings (TLG) with high arsenic (As) content on sites at the Essakane gold mine. Trees were assessed for growth and survival 3 years after planting. In experiment 2, soil was sampled on four sites across a disturbance gradient from mining waste (WR and TLG) and artisanal gold mining to undisturbed natural soil (NS). Each soil was planted with two separate leguminous trap crops (cowpea and umbrella thorn) in pots to check for microsymbionts. At 3 years, trees grew better on TLG soils with greater arsenic contamination than WRs in the field. Although tree establishment was moderate, with <50% survival, overall results suggest the ability of umbrella thorn to tolerate As contamination levels up to 1,300 ppm and, therefore, its potential for reforestation. Soil pH has shown strong effects on soil nutrient content. In particular, ammonium was the dominant form of mineral nitrogen (N) in the more neutral pH NS soils, while nitrate was present in the more alkaline WRs. Denitrification likely resulted in high N loss where nitrate dominates, reflecting the poor performance of N-deficient trees on WRs compared to TLG soils. Growth trends of umbrella thorn in potted-soils were consistent with those reported on TLG and WR soils in plantations.

IDENTIFICATION OF FACTORS DETERMINING MICROBIOLOGICAL ACTIVITY OF BIOCENOSIS

It is important to establish methods and approaches that ensure phytosanitary recovery of agrocenoses. Phytosanitary recovery of agroecosystems of fodder crops is possible by pre-treatment of seeds, application of mineral and organomineral fertilizers in order to increase resistance of plants to diseases and soil suppressiveness to phytopathogens. The aim of the research was to establish the influence of mineral, organomineral fertilizers and preparations for pre-treatment of seeds on the microbiological activity and suppressiveness of the soil in the rhizosphere of spring barley, peas and spring rapeseed. Field and laboratory studies were carried out on the pilot field and in the laboratories of the FSBOU VO Kurgan GSHA from 2001-2020. Studies have found that the introduction of mineral fertilizers into the soil changed the number of the main ecological-trophic groups of microorganisms in the rhizosphere of plants (bacteria that absorb organic and mineral forms of nitrogen, nitrifiers, cellulose-decomposing and denitrifying bacteria, oligonitrophilic and nitrogen-fixing bacteria). When introducing mineral fertilizers, an increase in cellulosic, proteolytic, catalase, invertase and total biological activity of the soil was noted. When introducing mineral fertilizers in the rhizosphere of spring barley, soil suppressiveness increased to 56.7-63.2% in relation to root rot pathogens. There was a negative correlation between soil suppression and the development of root rot of spring barley, which was -0.93, the regression equation was as follows: y = 47.08-0.05x. Soil suppressiveness against pea fusariosis pathogens increased with the introduction of mineral fertilizers by 32.2-46.0%. The correlation between soil suppression, development of pea fusariosis was -0.90, respectively, the regression equations were as follows: y = 54.11-0.05x. Soil suppressiveness against root rot pathogens and rapeseed fusariosis increased to 43.7-48.4% or 2.2-2.3 times compared with control.

Агрохимические свойства почв коллекционных питомников Полярно- альпийского ботанического сада

The current state of soil fertility was estimated at 2 sites of experimental fields of the Polar-Alpine Botanical Garden. Soils in both areas are characterized by a light granulometric composition. The sites vary in the content of organic matter in the soils, as well as the acidity and proportion of the sites where the liming is needed. The availability of phosphorus at all sites in both areas is characterized as high, potassium — from medium to high, mineral forms of nitrogen — as very low.

THE EFFECT OF DIFFERENT DOSES OF ORGANIC FERTILIZER ON THE MICROBIAL COMPOSITION OF SOUTHERN CHERNOZEM

In this paper, the effect of various doses of organic fertilizers from bird droppings on the spread of microorganisms in the rhizosphere of barley is investigated. Microbiological activity of southern chernozems was carried out before sowing barley. The use of organic fertilizers increased the predominance of the number of nitrogen-fixing bacteria absorbing ammonifiers and mineral forms of nitrogen, compared with fungi and actinomycetes. The favorable period for the growth of actinomycetes differentiated in the Gause nutrient medium coincided with the period of full ripeness of barley and a positive effect on their distribution on the variants 5 t/ha and 10 t/ha was noted. Cellulose destroying actinomycetes showed predominant results in relation to fungi, which is an indicator of the intensive destruction of plant residues and organic compounds in the soil. Studies show that increasing the dose of organic fertilizers in experimental variants has an adverse effect on the spread, growth and development of fungi. This may be due to the composition of the biological product used for composting organic fertilizers. The use of bird droppings in high doses promotes the reproduction of nitrogen-fixing bacteria.

Evaluation of the ecological and geochemical state of surface water in Donbas

The article covers evaluation of the ecological and geochemical state of surface water and bottom sediments in Donbas, as well as their pollution resulting from spatio-temporal changes of natural and anthropogenic factors. It was established that chemogenic pollution occurs due to penetration of polluting elements into surface water as a result of filtration leaks from sedimentation tanks and water discharges made by enterprises of coal, chemical, metallurgical, coke-chemical and petrochemical industries. Increased concentrations of biogenic elements (mineral forms of nitrogen and iron) were recorded in the water of the Siverskyi Donets and the Luhan Rivers. The most significant deterioration of groundwater quality because of high content of sulfates and chlorides is observed within the watersheds of the Luhan River's valley.
 Measurement results of the metals content indicated an increased content of copper and manganese. Some values even exceed the average annual concentrations specified by the existing normative values. In general, the results of the pollutants content analysis in the river basins under study did not reveal significant changes in the content of heavy metals during the period of military actions as compared to the results of government monitoring by 2014. The obtained experimental data indicate that vanadium, chromium and copper dominate in bottom sediments of all the studied objects. The greatest accumulation of heavy metals is observed in the Bakhmutka River and the Kryvyi Torets River. The research established that copper and plumbum in the bottom sediment samples taken from the Kryvyi Torets exceed the background values by 4-5 times. Zinc and vanadium exceed the background content values by 10 and 4 times, respectively. The same indicators are slightly lower in the Volyntsevske Reservoir and this fact is associated with more intense processes of water exchange and certain peculiarities of bottom sediments granulometric composition. Concentration of zinc is 3 times as much as the background level, vanadium and manganese – twice as much.
 Heavy metals in the bottom sediments of the studied water bodies are characterized by uneven distribution. Vanadium and copper dominate in the content of bottom sediments. Concentrations of zinc, vanadium and nickel at certain objects also exceed their regional background content values. Titanium was detected in minimum quantities.