Nº 4 (2024)

In the leached low-humus medium loamy chernozem of the central zone of the Kurgan region, losses of nitrate nitrogen through leaching with precipitation down the soil profile were noted. Losses increased with the use of increased doses of nitrogen fertilizers, as well as in variants with unilateral application of nitrogen fertilizers.

The effect of long-term application of increasing doses of mineral (from N90P75K100 to N360P300K400) and organic (cattle manure from 25 to 100 t/ha) fertilizers on the fertility of gray forest soil was studied in the micro-plot experiment. Over 9 years, 0.81–3.24 t/ha of nitrogen, 0.68–2.70 t/ha of P₂O₅ and 0.90–3.60 t/ha of K₂O were applied with mineral fertilizers. Manure supplied 43–173 t/ha of dry matter, 16–65 t/ha of C_org, 0.85–3.41 t/ha of N_tot, 0.65–2.59 t/ha of P₂O₅ and 0.86–3.46 t/ha of K₂O. In the yield the mineral fertilizer system exceeded the organic one by an average of 29%. At extreme doses (N360P300K400 and 100 t/ha of cattle manure) mineral fertilizers reduced crop productivity more strongly than organic fertilizers. A direct linear relationship was found between the doses of mineral and organic fertilizers and the increase in the content of available P₂O₅ and K₂O in the soil. Application of extreme doses of fertilizers did not lead to saturation of the soil with available forms of phosphorus and potassium. Long-term application of organic fertilizers increased the soil pH_(KCl) by 0.4–1.3 units and mineral fertilizers decreased it by 0.8–1.4 units. Annual application of mineral fertilizers increased soil C_org content by an average of 0.02–0.04% per year, and organic fertilizers – by 0.08–0.17% per year. Manure application at 100 t/ha over 9 years led to the saturation of the soil with organic carbon. The C : N ratio in the soil under a mineral fertilizer system was decreased, while it with the organic system was increased. An approach to calculate the carbon sequestration efficiency for the assessment of different agronomic practices is proposed. It is shown that the carbon sequestration efficiency of the organic fertilizers was 15% higher than that of the mineral fertilizers.

In a long-term 10-variant microfield experiment based on a mediumacidic sod-podzolic light loamy soil, a comparative study of the reclamation properties of the screening of dolomite crumbs stored in dumps, without separation into fractions (SIF), particles of 5–7 and 7–10 mm in size and dolomite flour (DF) prepared from the screening of dolomite when sifting dolomite crumbs with the diameter of the holes is 0/25 mm. The experiment lasts for 14 experimental years. It has been revealed that dolomite particles of 5–7 and 7–10 mm in size are valuable calcareous material. Their use leads to the neutralization of soil acidity already in the year of liming. The higher the dose of application, the greater the reclamation effect. There were no significant differences in the effect of granules of 5–7 and 7–10 mm in size, applied in equivalent doses, on the pH value. The positive effect of liming with meliorant in the amount of 3 and 5 doses of hydrolytic acidity (Ah) did not end after 14 experimental years after reclamation and allowed to postpone the period of repeated (maintenance) liming. The positive effect of using a natural mixture of chalk fractions (SIF) in a scientifically justified dose was inferior to dolomite flour. Clustering of individual variants of the experiment was carried out according to their effect on the рHKCl value for the entire period of the experiment. Linear trends of the averaged dependencies of the acidification process for meliorant particles of various sizes over the entire period of the experiment have been developed. The mechanisms of interaction of dolomite particles with soil in the process of land reclamation are considered.

The effectiveness of the use of lignohumate on lettuce (annual, green crop) and peppermint (perennial, medicinal plant) grown under the conditions of vegetation experiments was studied. The combination of lignohumate with the introduction of chelated fertilizers containing trace elements (zinc, copper) into peat showed a significant positive effect in obtaining high-quality plant products. The most effective was the fertilizer system, which included a combination of lignohumate with chelated forms of zinc and copper: the increase in lettuce biomass was 29–32, mint – 71–79%, the content of macroand microelements in plants became optimal.

On mediumcultivated mediumloamy sod-podzolic soils of the Central NonChernozem region, well provided with mobile phosphorus and potassium (IV–V class), the cultivation of lupine–cereal mixtures for grain with the participation of narrowleaved lupine varieties Ladny, spring wheat, barley and oats varieties of Nemchin breeding after grain precursors in a changing climate ensured grain production in an average of 5 up to 3.0–3.7 t/ha with a share of the legume component of 29–57% and the remaining dry mass of plant residues in the soil up to 6–8 t/ha with the accumulation of total nitrogen in it up to 40–60 kg/ha and biological – 12–17 kg/ha. In arid conditions (GTK = 0.80–0.92), a mixture of lupine and barley was distinguished for the better in terms of yield and weight of plant residues, and in case of waterlogging (GTK = 2.47) – mixtures with oats and spring wheat. The inclusion of liquid micronutrients of organic nature in the technological process with a stimulating effect for non-root top dressing eliminated the need for pre-sowing application of nitrogen fertilizer and, in conditions of moderate aridity, increased grain yield, depending on the composition of the mixture, to 3.9–4.9 t/ha (by 53–59%), the yield of plant residues – up to 7–11 t/ha (by 54–139%) and in them there is an accumulation of symbiotically bound nitrogen – up to 15–25 kg/ha or 5–8 times more than without their use.

In model experiments in soil culture, the effect of various methods of applying sodium selenite on the formation of yield and amino acid composition of grain varieties of spring wheat Zlata and Ester, depending on water supply conditions, was studied. Sodium selenite was introduced by pre-sowing seed treatment and leaf treatment of vegetative plants. The study simulated optimal water supply conditions and soil moisture deficiency during the critical period of plant growth. The role of selenium in the regulation of the production process and the formation of the amino acid composition of spring wheat grain was studied. It was found that the production process of wheat plants, both under optimal water supply and in drought conditions, depended on the method of application of selenium and the varietal characteristics of spring wheat. The results allowed us to assume that selenium activated the attenuating ability of the ear by enhancing its acceptor properties. Under these conditions, the grains were better provided with assimilates. this made it possible to form the maximum possible yield of wheat grain. In conditions of drought, during leaf treatment of plants with sodium selenite, favorable conditions were created for the formation of reproductive organs of wheat, which stimulated the restoration of the processes of assimilate outflow from the vegetative mass into the forming grains. This made it possible to influence production processes and reduce the depression of wheat crop formation. The use of selenium revealed an increase in the total content of key amino acids, which had a significant effect on the antioxidant status of plants and contributed to the realization of their adaptive potential. The positive effect of selenium on the content of a number of amino acids, including on the assimilation of methionine, was revealed, which was probably due to the synthesis of selenomethionine, since the ways of their formation are similar and it is not possible to separate them. The greatest effect of selenium was observed in the cultivation of wheat of the Zlata variety compared with wheat of the Ester variety, which was determined by varietal differences inherent genetically and the unequal protein content in the grain.

The influence of gold mining on the concentration of chemical elements in Betula pendula Roth leaves was studied. The intensity of absorption by the plant of a number of chemical elements, the possibility of using birch as a medicinal and forage plant, as well as for monitoring habitat changes were investigated. The study was conducted in plant communities located at production facilities and natural habitats in the area of the Baley gold deposit: tailings dumps of gold recovery factories (ZIF-1 and ZIF-2), a drainage landfill, a dump of the SredneGolgotai gold deposit, a tailings dump after processing monocytes, as well as in natural plant communities located in the vicinity of Baley at 13 trial sites in 2008, 2008 and 2021. The concentrations of elements in the leaves were arranged in descending order in the following sequence: Ca > Mg > P > Mn > Fe > Zn > Na > Ba > B > Cr > Ni > As > Cu > Mo > Sb > Pb > Co > Li > V > > Cd > Bi > Se > Be. With respect to the clark of terrestrial plants, the concentrations of the elements were in the following order: Cr > As > Sb > Li > Ni > Ba > Fe > Mo > Bi > Co > Zn > Mg > Clark > > Mn > P > Ca > Cu > B > Pb > Se > Cd > V > Be > Na. The absorption of As at production facilities exceeded the norm established for medicinal plant raw materials. The use of branch feed in a number of areas is not allowed due to the high level of Zn, Fe, Sb, Ni, Cr, Co, As, Cd. A relatively high coefficient of biological absorption by birch leaves Zn, Mn, P, Ca, Mg was obtained.