№ 11 (2023)

In micro-field experiments conducted on gray forest soil, changes in the forms of potassium under the influence of mineral fertilizers and plant residues were studied. It is shown that the soil potassium contained in a water-soluble and easily exchangeable form varied widely. In the conditions of 2012, when applying K60 on the background of nitrogen and phosphorus, the content of water–soluble potassium increased by about 2 times compared with the control, and the content of light-exchange potassium increased by 4 times. In the case of embedding plant residues in the soil, the potassium content in the water–soluble form increased by 2 times, light-exchange – by 2.5 times, respectively. The content of exchangeable potassium changed little in the variants, the changes affected the non-exchangeable form to a greater extent. In particular, the content of non-exchangeable potassium in 2018 decreased by 1.5–2.0 times compared to 2012, which required the creation of a more reliable basis for obtaining objective information about the state of the potash fund of the soils of the forest-steppe zone. Under the influence of K-fertilizers in combination with plant residues, plant productivity stabilized, and at the same time a positive balance of potassium in the soil was formed.

In a 52-year stationary experiment at the Central Experimental Field of the Kurgan Research Institute, the effect and aftereffect of phosphorus fertilizer against the background of nitrogen application were studied. A dose of P40 in combination with nitrogen, introduced for 25 years in the corn–two wheat–oats crop rotation (in the amount of P1000), after discontinuation of use, had a long aftereffect in sowing permanent wheat after stubble. In the experiment, the economic efficiency of the action and aftereffect of a dose of phosphorus P1000 was evaluated. Taking into account the 27-year aftereffect, the payback of the phosphorus dose of P40 added to N40–50 increased from 9.0 to 15.5 kg/kg.

The results of three years of research on the development of a biological biocidal preparation for the control of harmful arthropods based on ethanol extracts of biologically active substances of Lobel’s hellebore are presented. The first experimental samples of the drug were tested on a number of arthropod phytophagous species. In laboratory experiments, the most effective and promising samples of the preparation for further research were determined. It has been established that their biological effectiveness depends on the technology of manufacturing preparations, the content of the active composition of substances, the concentration of the working solution and the species of phytophages. Individual samples were comparable in effectiveness with traditional insecticides from the avermectin group.

In a series of consecutive vegetation experiments on biotesting on samples of sod-podzolic cultivated soil after its treatment with herbicides from the class of sulfonylureas: Magnum, VDG, metsulfuron-methyl 600 g/kg, manufactured by August and Alistair Grand, MD, diflufenican 180 g/l + mesosulfuronmethyl 6.0 g/l, iodosulfuron-methyl-sodium 4.5 g/l + mephenpyrdiethyl 27 g/l (antidote), manufactured by Bayer. The residual phytotoxicity of these preparations for seedlings of sensitive cultures of white lupin (Lupinus albus) and masha (Vigna radiata) was studied. The initial soil samples were taken in the field on the 5th day after herbicides were applied in the field in winter wheat crops using 2 different tillage technologies: traditional on the basis of dump plowing and zero tillage. According to the results of biotesting samples at a temperature of 20°C and humidity at the level of 60% soil moisture capacity, it was shown that the half-life of herbicides (DT₅₀) was reached after 40 ± 3 days of incubation, and detoxification to the level of 70–80% occurred 200–240 days after the introduction of herbicides into the soil. Regardless of the method of tillage and the applied herbicide, 2 years after the application of herbicides, the suppression of test crops at the level of  >10% of the control was detected. White lupin and mash are highly sensitive to the effects of micro-quantities of herbicides of the sulfonylurea group, therefore it is recommended to use these test cultures to determine the residual phytotoxicity of the soil. The manifestation of the aftereffect of sulfonylureas on legumes is shown, which is important even in specialized crop rotations designed for zero tillage.

The issues of improving the quality of application of fungal and bacterial biological products when applying the flow rates of working fluid up to 20 l/ha are considered. Along with the traditional methodology for assessing the quality of applying the working fluid of biological products to the treated surface, a new method for evaluating the effectiveness of applying biological products was also used, which consisted in selecting a certain area of the potato leaf surface by plant tiers 1 day after processing to determine the viability of fungal and bacterial preparations with low-volume (LV) and ultra-low-volume (ULV) technologies spraying. It is shown that when applying the technology of spraying up to 10 l/ha, despite the high coating density, the cells of microorganisms fall on the leaf surface with an insufficient amount of liquid for their active reproduction on the treated surface. In addition, at low humidity, due to the rapid evaporation of droplets from the surface of the treated leaves, microorganisms do not multiply and are carried away by the wind when drying. The conducted research tests of the use of the mushroom biological preparation Trichocin at a consumption rate of 20 l/ha on test objects (potato plants of the Galla and Riviera varieties) using especially pure glycerin and the moisture-retaining food additive sorbitol as antiparators showed that their use ensured the viability of the cells of the biological product and the high rate of their reproduction on the treated surface due to moisture retention.

In a 24-year vegetation precision experiment based on acidic sod-podzolic sandy loam soil reclaimed with conversion chalk (CC) in a wide dose range, the effect of liming on the content of calcium available to plants in the soil and its translocation into rapeseed tissue was established. The results showed that rapeseed is an ecologically plastic plant species. An increase in the amount of chalk introduced from 0.1 to 3 full doses calculated by hydrolytic acidity led to an increase in the Ca concentration in rapeseed in the liming year from 0.81 to 3.14%. Empirical dependences of calcium concentration in soil and plants on the dose of chalk application have been developed. 3 approaches to the analysis of experimental data describing the relationship of calcium content in the soil with its accumulation in plant tissues are considered. It is shown that artificial averaging of the data on the calcium content in the soil with the same dose of meliorant in individual repetitions led to loss of information, which was reflected in the statistical characteristics of the constructed empirical models.

In a 3 months model experiment, the effect of application of sewage sludge (SS) at doses of 40 and 80 g/vessel (in terms of dry mass corresponds to 5 and 10 t/ha) in combination with straw, kieselguhr and sapropel, on the nitrogen state of leached, slightly eroded chernozem, was studied. It is shown that the addition of kieselguhr and sapropel to SS, unlike of straw, improves the parameters of the soil nitrogen state. A raise of the SS dose leads to a significant increase of the alkaline hydrolysable nitrogen content. The ability of ameliorants with SS to enrich the soil by mineral nitrogen can be arranged in the following descending row: suspended kieselguhr > dry kieselguhr > sapropel > SS severally > straw. A double dose of SS does not differ significantly from a single dose in terms of its influence on the contents of total and mineral nitrogen, humification and soil acidity; the use of high doses of SS is rational for waste disposal.