№ 2 (2023)

The results of studies of the agrochemical properties of meadow differentiated soils of reference plots that have been in agricultural circulation for a long period are presented. The humus content, exchange acidity and the degree of saturation with bases have not changed much over 35 years of intensive soil use in agriculture. A decrease of hydrolytic acidity and the content of available phosphorus, as well as a significant increase in the content of exchangeable potassium was revealed. A trend towards a decrease in the content of exchange bases was noted. The calculated complex indicator of the agrochemical state of the soil indicates the multidirectional change in soil fertility in the studied areas, which is associated with differences in the availability of mobile forms of phosphorus and humus. The need for the widespread application of phosphorus fertilizers and a decrease in the differentiation of soil fertility in various areas has been identified.

The analysis of the results obtained over 48 years in a long stationary experiment with fertilizers, which is located in the Saratov region (Russia) on the southern heavy loam chernozem, is presented. The influence of various types and doses of mineral fertilizers on the productivity of 6-field crop rotation, yield and grain quality of cultivated crops (winter and spring wheat, millet, barley, oats) has been studied. The optimal doses of fertilizers for the arid steppe of the Volga region have been identified, providing maximum yield increases and the greatest payback of 1 kg of mineral fertilizers. The influence of the conditions of humidification of the growing season on the yield of grain crops, the accumulation of protein in the grain and the removal of nutrients from the soil is shown. The scales of carbon losses, gross nitrogen and phosphorus reserves have been established both in untreated soil and with the systematic application of various doses of mineral fertilizers over 48 years of observations.

Excessive fascination in vegetable growing with mineral (especially nitrogen) fertilizers has led to significant contamination of soils and products with nitrate, heavy metals, and other toxicants. The scientific literature has accumulated considerable material on the use of various kinds of fertilizers, especially mineral fertilizers. A well-established trend towards the development of organic farming on a global scale requires a more indepth study of the effect of organic fertilizers on vegetable yields and adjustments to previously developed fertilizer systems for vegetable crops. The research was carried out by the Department of Agriculture and Agrochemistry of the All-Russian scientific research institute of vegetable growing-branch of the Federal scientific center of vegetable growing and three experimental stations of the Institute on sod-podzolic, alluvial meadow soils, typical, ordinary and leached chernozems in the Non-chernozem zone, the North Caucasus and Western Siberia. It was found out that the efficiency of the use of cattle manure on average for 6 crops on 6 types of soils was 33% of the increase in yield. The highest increases were found in cucumber (62%) and table beet (54%) crops; cabbage and carrots increased yields by 27 and 22%, respectively, tomato and onion - by an average of 17%. The efficiency of manure was inversely proportional to the amount of humus content in the soil. Studies of the effectiveness of the use of biocomposts based on chicken manure revealed that the biocompost increased the yield of 12 vegetable crops on alluvial meadow soil by an average of 20, mineral fertilizers - by 28%, the joint application of these fertilizers allowed to increase yields by 35%. Green fertilizers (siderates) in the conditions of the Central Processing Plant allowed to increase the yield of vegetables by 8-15%, peas, pea mixture and phacelia turned out to be the most effective, yellow lupin and sunflower were ineffective. In the irrigated conditions of the Rostov region, the complex application of mineral fertilizers, manure and siders increased the yield of vegetable crops from 23.6 to 49.6 t/ha, i.e. by more than 2 times.

The results of the evaluation of the biological efficacy of the combined insecticide Eforium, CS (thiamethoxam 141 g/l + lambda-cyhalothrin 106 g/l) and the insectofungicide Vibrans Top, CS (thiamethoxam 262.5 g/l + fludioxanil 25 g/l + sedaxan 25 g/l) and ecotoxicological indicators of these drugs are presented. Based on the data obtained, it is concluded that it is advisable to use these drugs in potato protection systems against the Colorado potato beetle in accordance with the established regulations for use, provided that these drugs are available in the “State Catalog of Pesticides and Agrochemicals approved for use on the territory of the Russian Federation”.

Organic substances (sawdust, straw, leaf litter, needles, peat, sunflower husk, charcoal), synthetic moisture regulator (Aquaterra hydrogel), mineral adsorbents and diluents (glauconite sand, diatomite, vermiculite) were used as reclamation agents to optimize the ecological state of the soils of the enclosures of the Rostov-on-Don Zoo, agroperlite, zeolite), biological products (Tamir, potassium humate, Baikal EM), as well as a combination of potassium humate and sawdust). The best results were obtained when applying sawdust in doses of 5 and 10% of the soil weight. At the same time, biological processes in the soil intensified, which increased its ability to self-purify from animal metabolic products. The introduced sawdust mineralized with a strong increase in carbon dioxide emissions. The content of organic carbon in the soil at the same time by the end of the experiment (after 6 months) practically did not change.

This study focuses on the impact of pre-planting irradiation of seed potatoes on the phenophases of the root crop and proliferation of fungus Rhizoctonia solani on the new crop tubers. A two-year monitoring of seed potatoes after irradiation shows that treatment of tubers with 30-40 Gy decreases the spread of fungal infection on the surface of the tubers. It was found that low-energy electrons, used in the experiment, are the most effective irradiation treatment, since they penetrate in the upper layers of potato tubers affected by the fungus.

The effect of synthetic analogues of cytokinins - cytodef and tidiazuron - on the growth, development and productivity of cucumber plants grown in protected soil was studied. Cucumber plants at the stage of 3-4 leaves were planted from garden pots into the ground and treated with cytodef solutions at concentrations of 10^-9-10^-6 M/l or tidiazuron at concentrations of 10^-11-10^-6 M/l. During vegetation, the timing of the passage of phenological phases was noted, the height of plants, the number of leaves, flowers (male and female), fruits (at the beginning of fruiting) were periodically changed. The productivity of cucumber plants was determined by means of periodic (after 1-2 days) collections. It was revealed that the treatment of young plants with different concentrations of drugs favorably affected the growth of cucumber; the best results were obtained at a concentration of tidiazuron 10^-8 M/l and cytodef - in doses from 10^-8 to 10^-6 M/l. Treatment of cucumber plants with cytodef and tidiazuron increased plant productivity and the yield of the fruits obtained. Under stressful temperature conditions, the preparations contributed to the better condition of the plants.

Optimal conditions of gas chromatographic analysis with mass spectrometric detection (GC-MS) were selected, which allowed to obtain satisfactory separation and identification of some organochlorine (OCP) and organophosphorus (OPP) pesticides. Several sorbents were studied at the stage of extract purification in order to reduce the matrix effect in order to achieve higher analysis accuracy. The completeness of the extraction of OCP and OPP from the apple matrix was evaluated using the example of the following pesticides: hexachlorocyclohexane (HCH, α-, ß- and γ-isomers), dimethoate, phosalone, chlorpyrifos. It was found that the most effective was the use of Florisil sorbent in combination with MgSO4, which allowed to minimize matrix effects and obtain the best indicators of the extraction degree of the investigated analytes. This method was used to monitor the content of residual amounts of pesticides in apples of different varieties.

Currently, in industrial agricultural production, the best results are demonstrated by technological schemes for weed control based on the use of complexes of non-selective and selective herbicides in crop rotations. Herbicides of the imidazolinone group are well-known representatives of selective herbicides class. Commercial drugs based on them are widely represented on the market. At the same time, the negative consequences of using herbicides of the imidazolinone group are well known. They lead to disruption of natural soil biodiversity, inhibition of growth and decreasing in the yield of subsequent crops in crop rotations and the emergence of resistant weeds. The manuscript discusses the mechanisms of action of herbicides of the imidazolinone group, the current state of methods of their analysis in the soil, as well as approaches to reducing the negative effects of their usage.