No 1 (2025)

In a field experiment in the link of the grain-grass crop rotation (barley with sowing of clover and phleum –perennial grasses of the 1st and 2nd year of use), changes in the acid-base properties of sod-podzolic light loamy soil during periodic liming were studied in order to establish optimal doses of lime with its long-term periodic use. A comparison of the average yields of barley grain and hay of perennial grasses over 3 years of testing in variants with single and periodic liming showed the advantage of periodic lime application in a dose of 1.0 H_a. In the variant with periodic lime application of 1.0 H_a, the acidity was significantly lower than in the control and in the variants with doses of 0.5 and 0.25 H_a, while the latter variants did not differ significantly in terms of acidity. Periodic liming led to a significant decrease in the content of Al³⁺, Fe and Mn. At the same time, there was a significant increase in S and V indicators and a decrease in H_a. No significant changes in the content of phosphorus, potassium and humus under the influence of periodic application of lime have been established. It was shown that the optimal dose of lime for its periodic use is 1.0 H_a.

The effect and aftereffect of agrochemicals obtained by mesophilic-thermophilic composting of organogenic by-products (manure of cattle, bird droppings and a mixture of urban wastewater sediment with sawdust) on the nitrogen regime of sod-podzolic sandy loam soil, the productivity of cereals in the crop rotation, their macronutrient composition were studied. It is concluded that these agrochemicals based on by-products of animal husbandry and sewage sludge significantly influenced the nitrogen regime of the soil, the productivity of the grain component of crop rotation and the macronutrient composition of crops.

In an experiment on typical deep, heavy loamy chernozem conducted in 2018–2020 in the Kursk FASC, the effect of various doses of sulfur-containing fertilizer NPKS(10–20–20–6) on the yield and quality of pea grain of the Pharaoh variety was studied in the following variants: 1 – control without fertilization, 2 – NPKS(10–20–20–6) at a dose of N20P40K40S12 from autumn for basic tillage + N20 (ammonium nitrate) in spring for pre-sowing cultivation, 3 – NPKS(10–20–20–6) at a dose of N30P60K60S18 from autumn for basic tillage + N30 (ammonium nitrate) in spring for pre-sowing cultivation, 4 – NPK(16–16–16) at a dose of N40P40K40 (250 kg/ha) from autumn for basic tillage, 5 – NPK(16–16–16) at a dose of N60P60K60 (375 kg/ha) from autumn for basic tillage. It was shown that in conditions of chernozem soils with a low level of sulfur availability (4.5 mg S/kg), its introduction into the soil as part of the complex mineral fertilizer NPKS(10–20–20–6) increased the yield of peas by 1.9–1.6 c/ha, the protein content in the grain – by 0.4–0.5% compared to the application of a complex mineral fertilizer without sulfur (NPK16–16–16). The use of sulfur-containing fertilizer NPKS(10–20–20–6) in pea crops was economically profitable: the net income from its application was 3 901–6 612 rubles/ha, the profitability level was 68.0–85.4%, with the values of these indicators in the control variant equal to 15 312 rubles/ha and 65.9%, respectively. Increasing the dose of sulfur-containing fertilizer NPKS(10–20–20–6) to N60P60K60S18 was not economically feasible.

Jasmonic acid (JA) and its derivatives are involved in the adaptation of plants to biotic and abiotic stresses, including salinization. However, there is insufficient information about the role of JA in the transmission of signals from organ to organ under the local action of abiotic factors. The signaling role of JA in connection with the reaction of shoots to salinization of the root environment of pea plants has been studied. The results of the effect of salinization on changes in the content of JA in the growing and conducting zones of roots and xylem sap, as well as the localization of JA and abscisic acid (AA) in the leaves of stressed plants due to changes in their transpiration level are presented. The content and localization of JA in leaves and roots of plants were evaluated by immunohistochemical method using specific antibodies. The purpose of this study is to check whether salinity-induced changes in the concentration of JA in roots and xylem sap can explain the accumulation of these hormones in leaves and related transpiration changes.

The reserves and chemical composition of grassland litter and felts in monodominant Leymus chinensis communities of the southern part of Eastern Transbaikalia, growing in different soil and ecological conditions of a distinctly continental climate and performing protective functions in winter for the thermal and water regimes of the upper soil horizons, the preservation of plant renewal buds, are studied. It was revealed that the stocks of grassland litter and felts varied significantly: 2.9–102.9 and 54–107 g/m², respectively. The amount of grassland litter mainly depended on the species composition of communities and the degree of pasture load. A correlation was established between the accumulation of grassland litter and felts from the dominant production and the total green phytomass of leymus communities, but the relationship between the content of grassland litter and felts in leymus communities was weak (r = 0.44). To restore the optimal accumulation of rags, according to the values of the litter fall coefficient (LFC) and the destruction coefficient (Kd), will take a relatively long time. A high negative correlation between these indicators was revealed (r = – 0.89... –0.91). Concentrations of macronutrients in grassland litter and felts from different communities were determined by species composition and availability of nutrients and moisture. According to the values of the C : N, C : P, C : N : S : P, Ca : K and Si : Ca ratios in the aboveground phytomass of communities, it was shown for the first time that the grassland litter and felts of leymus communities in the southern part of Eastern Transbaikalia are resistant to decomposition and mineralization. However, the degree of stability can be adjusted with changes in species composition, climatic (drought, heavy rainfall) and anthropogenic (spring snowfall and steppe fires) conditions.

The results of studies of the nitrogen regime of oil-contaminated soils in recent years are considered. Insufficient knowledge of this issue for man-made soils is emphasized, despite the fact that soil pollution with oil and petroleum products can cause significant changes in the nitrogen cycle and lead to irreversible violations of the ecological functions of soils. The generalization of the research results made it possible to identify the most informative indicators for assessing the processes of the nitrogen regime and the ecological state of oil-contaminated soils. Under conditions of oil pollution, the ratio of carbon and nitrogen contents in the soil increases, the nitrifying activity of soils decreases, and the proportion of ammonium forms of nitrogen increases relatively. It is shown that violations of the processes of the nitrogen cycle, the content and the ratio of the contents of different forms of nitrogen characterizing certain stages of its transformation in the soil can be restored to varying degrees during reclamation, depending on the properties of the soil. At the moment, the most promising areas of research into the processes of the nitrogen cycle in oil-contaminated soils are: the study of the vital activity of soil microorganisms carrying out various stages of the nitrogen cycle processes, the relationship of the structure and diversity of the microbiota with the rate of biodegradation of oil and transformation of nitrogen compounds in contaminated soils. The study of the nitrogen cycle processes is important for assessing the effects of soil pollution with petroleum products and choosing the most effective strategies for their restoration.

The degree of mobility (DM) of Cd, Pb, Cu and Zn in arable (0–20 cm) and sub-arable (21–40 cm) soil layers was studied when applying phosphorus-potassium and nitrogen fertilizers on the background of liming and without it. It was revealed that the values of the DM of heavy metals (HM) were mainly lower during liming. In Cu, it varied less significantly compared to other metals. Fertilizers on the background of liming significantly lowered the Cd loss compared to the control, and without it – increased it in both layers. The vector of changes in the DM of the metal in the layers during liming depended on the doses of nitrogen in the NPK complex. Phosphorus-potash fertilizers reduced the DM of metals, and liming enhanced their effect. The values of DM decreased to a minimum with the use of PK- and NK-fertilizers with a low dose of nitrogen in liming conditions and without it, and increased with a maximum dose of nitrogen. Liming increased the differences in the joint venture between the layers in the nitrogen-free versions, and significantly reduced them when applied. Liming did not change the location of the metals in terms of their DM under experimental conditions: Cd > Pb > Zn > Cu.

Many active substances of pesticides are dangerous toxicants that can disrupt the stability of natural and agricultural ecosystems and cause irreversible harm to human health when ingested. In addition, from several units to several dozens of new active substances of pesticides and products based on them are developed annually. This determines the critical need to control their use and content in environmental objects, especially in agricultural products. The development of modern chemical analytical methods helps to increase the effectiveness of such control. Improving the methods of extracting pesticides from extremely complex matrices of soils and agricultural products can significantly speed up and reduce the cost of conducting a single analysis, and improving analytical equipment allows to determine the picogram contents of target pesticides or conduct monitoring studies of samples to identify pollutants.