Agrohimiâ

In a long-term two-factor field experiment, the influence of biologization techniques on the state of peach agrocenosis in the foothills of the Crimea (Otradnoye village, Bakhchisarai district) on ordinary carbonate eroded chernozems was studied. The research was carried out in 2019–2021, the peach variety (Prunus persica (L.) Batsch) – Redhaven on almond rootstock (P. dulcis (Mill.) D.A. Webb). Two methods of biologization of agrocenosis were studied: blackening of the soil with segetal and artificial cereal-bean mixtures of herbs and the introduction of microbial preparations (MP) as biofertilizers – azotobacterin 07-agro (AB) and microbiokom-agro (MBK). It was found that both soil blackening and MP had a positive effect on soil properties, herbaceous and woody plants. Their more significant effect was revealed when used together. The maximum accumulation of grass biomass occurred in the variant of blackening with a mixture of herbs (Festuca pratensis Huds. + Trifolium pratense L. + Lolium multiflorum Lam. + Medicago sativa L. + Bromus inermis Leyss.) (MH4) in combination with AB, which was 3 times higher than the blackening of natural vegetation without MP (control of natural blackening (NB)). The biomass of seeded grasses contained more basic nutrients and carbon, the ratio of carbon to nitrogen was lower than in segetal vegetation, which contributed to its rapid mineralization with the formation of mineral nitrogen, and an increase in carbon content led to a more significant increase in the content of soil organic matter (SOM) compared with natural blackening. MP against the background of seeded grasses stimulated the accumulation of SOM in the soil, to a greater extent AB against the background of blackening with a mixture of MH4. The content of mobile forms of nutrients in the soil increased during biologization: nitrate nitrogen – by 12.5 mg/kg under the action of AB against the background of blackening with a mixture of F. pratensis + T. pratense (MH3), mobile phosphorus – by 13 mg/kg under the influence of MBK, K₂O – by 93 and 117 mg/kg when applying AB and MBK, respectively, compared with the control of NB. All this contributed to the improvement of the mineral nutrition of the peach, an increase in the content of essential nutrients in the leaves: nitrogen – by 0.9% under the action of AB against the background of MH4, phosphorus – by 0.07–0.09% under the influence of AB and MBK against the background of MH3, and potassium – by 0.6% when applying AB against the same background. All this contributed to an increase in the yield of peach fruits by 9–10 t/ha when using MP against the background of blackening with a mixture of MH3, as well as an increase in the content of nitrogen, phosphorus and potassium in fruits. The calcium content in fruits decreased during biologization, which was due to the high absorption of calcium by seeded grasses and the antagonism of calcium with nitrogen and phosphorus in fruits. The constructed model of the productivity of peach plants during biologization reflected the dependence of peach productivity on the content of elements in grasses, soil and leaves. Based on the studied complex of factors, it was found that when biologizing the peach agrocenosis, blackening the soil with a mixture of MH3 and the use of AB is optimal.

The influence of mineral and organomineral (NPK + cattle manure) fertilizer systems in crop rotation on the yield of grain crops and annual grasses has been studied in a long-term stationary experiment on gray forest soils of the Vladimir Opole. It was found that it was 84.3–98.5% dependent on N-NO₃ reserves formed during the growing season of crops. These reserves, with the combined use of cattle manure up to 80 t/ha for rotation of crop rotation and one-time N80 as part of NPK for culture, did not limit its yield. It is proposed to predict the yield of grain and hay of cultivated crops based on the relationship of the nitrogen mobilization pool with N-NO₃ reserves formed during the growing season of spring crops and from regrowth to harvesting of winter crops, and their utilization coefficients for nitrogen removal by grain and straw. The size of the formation of N-NO₃ reserves during the growing season and the coefficients of their use for takeaway products are estimated by zonal research institutions; the mobilization pool of nitrogen is calculated from the adopted fertilizer system. Data on nitrogen removal from products can be used from reference literature, more correctly from research data from research institutions. For grain crops and annual grasses of the 7-field crop rotation, a good agreement of the experimental yield with the calculated one was obtained. It has been reliably established that with an increase in the aridity of the growing seasons during the cultivation of spring cereals and annual grasses, the role of the nitrogen mobilization pool in the transformation of soil nitrogen into its mobile forms increases. It is shown that on gray forest soils of the Upper Volga region, when using organomineral fertilizer systems in a 7-field crop rotation, a single dose of N40P40K40 is optimal for the cultivation of grain crops, N60–75 – for the cultivation of annual legume-cereal grasses.

The results of agrochemical tests and evaluation of the effectiveness of fertilizers developed on the basis of agricultural ores of Karakalpakstan with the addition of NPK elements to improve the reclamation state of saline soils in the region are presented. Traditional mineral fertilizers, such as ammonium nitrate and superphosphate, are ineffective in saline soils, since the high salt content in the soil makes it difficult for plants to absorb nutrients and leads to a decrease in yield. In this regard, the aim of the study was to develop fertilizers based on local natural resources, such as phosphorite and glauconite, enriched with elements N, P and K, to increase soil fertility and their reclamation potential. An innovative technology for obtaining fertilizers has been developed, combining the use of agricultural ores of Karakalpakstan with nitrogen and potash fertilizers. Optimal conditions for obtaining fertilizers were experimentally determined: the formulations were tested in various concentrations of NPK elements in aqueous and acidic solutions. During the experiments, the effectiveness of these fertilizers in comparison with traditional types, such as ammonium nitrate and superphosphate, on the indicators of humus content, mobile phosphorus, acidity and the level of soil salinity was investigated. It is shown that the use of the developed fertilizers contributed to a significant improvement in the agrochemical parameters of the soil and created favorable conditions for the growth of crops. In addition, it was shown that the developed fertilizers had a positive effect on microbiological processes in the soil, contributing to an increase in the number of phosphate-mobilizing bacteria and an increase in microbiological activity. The presence of organic components, such as manure, created a favorable environment for the growth of heterotrophic microorganisms, which led to an increase in the content of organic carbon and improved humification. These processes contributed to the mobilization of phosphates, increased availability of nutrients for plants and accelerated mineralization of organic compounds. A comparative analysis of the developed fertilizers with traditional mineral fertilizers showed that the use of fertilizers based on agroores was more effective in terms of humus content and reducing the level of soil salinity.

In a series of model experiments, the effects of ultraviolet radiation on the soil microflora and some agrochemical parameters of the arable layer of sod-podzolic soil (Albic Glossic Retisol) of Republic of Mari El were studied. A 30-UVC bactericidal lamp was used for irradiation in a laboratory installation. The exposure time was 50 hours. Soil incubation was carried out at an optimal temperature and humidity (25°C, 60% full field moisture capacity) for 14 days. Agrochemical analyses of the soil were carried out using generally accepted methods. The number of the main ecological and trophic groups of microorganisms was determined by sowing various soil dilutions on agarized nutrient media. It was found that under the influence of ultraviolet radiation, the amount of mineral and easily hydrolyzable nitrogen in the soil increased, which indicated the photochemical destruction of humus and the formation of more mobile humic substances capable of leaching. A short-term decrease in the number of microflora involved in the mineralization of carbonand nitrogen-containing organic matter was revealed under the influence of ultraviolet radiation. At the same time, the sensitivity of microorganisms to ultraviolet radiation was as follows: spore-forming bacteria < actinomycetes < azotobacter < amylolytics < ammonifiers < micromycetes < nitrifiers. The change in the orientation of the transformation processes of organic matter towards the activation of mineralization processes and an increase in the provision of microorganisms with readily available nutrients is shown.

Scientific publications for the period 1990–2023 devoted to the study of the effect of exogenous amino acids on the physiological, biochemical, morphometric and molecular genetic parameters of crops, including under conditions of various stresses, were summarized and analyzed. Amino acid preparations are environmentally safe and harmless to agroecosystems. It has been shown that the considered processing methods contribute to the optimization of plant nutrition, improve physiological, biochemical and morphometric parameters, and mitigate the effects of various stresses. Proteinogenic and non-proteinogenic amino acids, used in different doses and in different phases of vegetation on various plants (melons, cereals, vegetables, fruits, essential oils, etc.), reduce the incidence of mycoses and bacterioses, have an immunomodulatory effect on plants, contribute to the stabilization of cell membranes, lower the content of reactive oxygen species and improve nutrition with potassium in salinity conditions. The simplest and most suitable methods for practical application in agriculture are foliar processing and priming of seeds. The active dissemination of the considered methods is hindered by an insufficient level of knowledge about the biochemical and physiological processes occurring in seeds and vegetative plants when treated with amino acids. To solve this problem, an integrated and interdisciplinary approach is needed, which will provide for development of practical recommendations for agricultural production.