№ 5 (2023)

The influence of dump and minimal agrochernozem processing technologies on the activity of nitrogen cycle enzymes and their role in the transformation of nitrogen-containing organic compounds was evaluated. The most significant differences in the seasonal dynamics of the fraction content of difficult-to-hydrolyze nitrogen compounds were found in the soil of the barley agrocenosis in all types of tillage. When using surface disking, the dynamics of their content was determined by the activity of protease. The high availability of the soil with easily hydrolyzable nitrogen was revealed, which indicated that there was no need for nitrogen fertilizers. The dependence of the dynamics of the content of easily hydrolyzable nitrogen compounds on the activity of protease was ambiguous. Under conditions of minimal tillage, the formation of easily hydrolyzable nitrogen compounds was inversely dependent on the proteolysis process. The plane-cutting method of loosening caused an increase in the level of urease activity relative to dump plowing and surface disking.

The dynamics of biomass and height of Secale cereale L. plants was studied in a long-term stationary field experiment on sod-podzolic light loamy soil. Systematic application of mineral fertilizers (option 2 – N65P50K50, option 3 – N100P75K75) had a significant impact on the height and biomass of plants at all tested stages of vegetation (eight time points within 50 days). To describe the dynamics of biomass and height of Secale cereale L. plants, sigmoid (logistic) and linear models are well suited, which made it possible to calculate such parameters as maximum biomass and height (M₂, g : H₂, cm), maximum speed (V_max, g ⋅ day^–1 (cm ⋅ day^–1)) and average speed (b, g ⋅ day^–1 (cm ⋅ day^–1)). The V_max values of the growth of raw plant biomass in variants 2 and 3 exceeded this indicator for the control variant by 1.7–2.0 times; V_max of plant height growth varied within 4.2–4.6 cm ⋅ day^–1, did not depend on the application of mineral fertilizers. The application of mineral fertilizers led to an increase in the average growth rate of the biomass of plants Secale cereale L. (b, g ⋅ day^–1), in relation to the control, by more than 2 times.

Currently, the widespread use of herbicides in agriculture creates a serious problem of further use of contaminated soils for growing various types of agricultural plants. Developing the research of aluminosilicates as detoxicants of herbicide residues contained in the soil, the effect of montmorillonite K-10 (MRT) on vegetative plants of spring rape and corn is studied in this work. It was shown that the introduction of MRT into the soil before sowing in low doses had a powerful stimulating effect on plant development, both in the presence of methsulfuron-methyl residues in the soil and in the absence of herbicide in the soil. The doses of the applied MRT were only 100–200 kg/ha, which created the prospect of widespread use of montmorillonite (bentonite) clays in crop production.

Fungi are one of the main sources of biotic inducers of plant immunity, but among this group of microorganisms, the largest number of phytopathogens is also noted. A two-year study was carried out on the dynamics of the composition and structure of the fungal community in the soil and the agrochemical characteristics of the soil of a young apple orchard of intensive type. The study of the fungi pool in the control (background, without plants) showed that the content of soil saprotrophs and cellulolytics was two times higher than the abundance of these groups in the root zone of a young apple tree. The importance of the role of plant exudates for the formation of the root zone mycobiota, its participation in the differentiation of the soil microbial community and the formation of the “phytogenic region” where root exudates affect the activity and distribution of ecological-trophic groups of fungi, is demonstrated. In the zone of intensive root growth in the 10–20 cm layer, a sharp decrease in the content of macroelements (nitrogen, phosphorus, potassium) was noted.

Mechanochemical modification of the substance of floroxan by the glycyrrhizic acid made it possible to increase the solubility of the preparation and expand the range and effectiveness of its action.

Stable functioning of agricultural lands is impossible without maintaining soil fertility. However, there are often a lot of crop residues in the fields, which decompose for a long time and turn into available organic matter. To increase the rate of decomposition of crop residues of grain crops (wheat, barley and others), it is necessary to introduce biostimulants. Biostimulants are a variety of substances that stimulate the decomposition of organic substances and have a beneficial effect on the soil microbiota. The article examines the influence of Bacillus sp. on the processes of decomposition of crop residues of wheat both independently and together with biochar. The aim of the study was to evaluate the phytotoxicity of ordinary chernozem during the decomposition of crop residues of winter wheat under the influence of Bacillus sp. and biochar. To assess the ecological state of the soil, the following research methods were used: assessment of the rate of decomposition of cellulose (determination of cellulolytic activity), assessment of the ecological state of the soil (intensity of CO₂ emissions, changes in the intensity of initial growth and development of winter barley (Hordeum vulgare L.)). Introduction of Bacillus sp. × 100 and the joint use of biochar and Bacillus sp. it stimulated the decomposition of cellulose up to 14–15% of the background content. Inoculation of Bacillus sp. on the biochar, it was effective already at the recommended dose both for the decomposition of the cellulose web and for restoring the ecological state of the soil, demonstrating a synergistic effect. The results obtained should be used in carrying out measures to increase soil fertility of agricultural lands and environmental monitoring of soil conditions.

Bioprotective materials for agriculture are an important part of the modern world. A wide range of different compounds are used for their development. For example, titanium dioxide, in addition to its protective properties, has a positive effect on the digestibility of nutrients, improves the efficiency of fertilizers and, accordingly, reduces their consumption, which is especially important in the modern world. However, direct injection of titanium dioxide is ineffective due to the processes of its loss. The best option is a prolonged isolation that provides the required concentration of titanium dioxide in the soil for the plant. The introduction of titanium dioxide into the polymer matrix can solve this problem by gradual release. In turn, such a polymer matrix has a number of requirements for their properties. A possible solution may be chitosan – a non-toxic, non-immunogenic, antimicrobial, biologically safe and biodegradable material. The paper considers the preparation of the composite material “chitosan–titanium dioxide” in granular form. The efficiency of a material with mass ratios of chitosan to titanium dioxide of 1 : 1, 2 : 1 and 3 : 1, as well as chitosan without titanium dioxide, has been studied. The structure and mechanical properties of the obtained composite materials are investigated.

The current knowledge on the prospects of using bacteria of the genus Pseudomonas as producers of effective microbiological preparations for the biocontrol of phytopathogenic organisms is summarized and analyzed. Rhizospheric pseudomonads are potential objects of agricultural biotechnology due to the presence of physiological and biochemical features necessary for biocontrol and phytostimulation. These features include tolerance to reactive oxygen species, chemotaxis in relation to root exudates, biosynthesis of siderophores and antibiotic metabolites of various nature. Members of the genus Pseudomonas are known for their great metabolic diversity, which allows them to colonize a wide range of ecological niches, including the rhizosphere. Pseudomonas species isolated from the rhizosphere have a broader catabolic activity than those isolated from the bulk soil, especially for certain sugars, polyols, and amino acids that can be found in root exudates. The wide metabolic diversity allows bacteria to become ubiquitous, forming protective biofilms and colonizing various ecological niches. At the same time, water-retaining capacity, fertility and porosity of the soil, as well as the conditions of mineral nutrition of plants are improved by increasing the availability of N, P, K and Fe. The paper describes in detail the main biologically active metabolites produced by Pseudomonas and their role in the suppression of phytopathogens and phytostimulation.