Agrohimiâ

Long-term agricultural use of leached chernozem in the 9-pole grain-and-beet crop rotation of the forest steppe of the Central Chernozem Region without the use of fertilizers contributed to a significant deterioration in a number of indicators of soil fertility (a decrease in the content of humus, total nitrogen, mobile forms of P₂O₅ and K₂O, deterioration of physic-chemical properties) relative to the virgin area. Prolonged application of fertilizers compensated for the loss of humus to varying degrees, contributed to the enrichment of mobile forms of P₂O₅ and K₂O, but somewhat worsened the acid-base properties of the soil. The N26.6P26.6K26.6 fertilizer system + 5.6 t/ha manure made it possible to preserve soil fertility to the greatest extent, and some a number of indicators – almost at the level of virgin land. The greatest change in fertility was observed in the 0–20 cm layer, the smallest – in the 40–60 cm layer.

In long-term field experiments on sod-podzolic heavy loamy soil, the yield of winter wheat of the Moskovskaya 56 variety and spring barley of the Vladimir variety, as well as grain quality, depending on the use of trace elements, was studied. The use of zinc and copper micro-fertilizers in the forms of ZnSO₄ and CuSO₄ on poorly cultivated soil provided the greatest efficiency on a calcareous background with a slightly acidic reaction of the soil medium: the yield increases of winter wheat and spring barley reached 12 and 8.6%, with its values against the background of mineral fertilizers 63.9 and 51.2 c/ha. The introduction of a complex of trace elements Akvamix-ST into cultivated soil increased the yield of winter wheat with a mineral fertilizer system by 13, organomineral – by 7.6%, spring barley – by 11 and 6.4%, respectively, reaching 76.4 and 59.8 c/ha. The use of trace elements slightly increased the protein content in the grains of both crops by 0.3–0.4% and the crude gluten content in winter wheat grains by 0.5–0.9%.

In modern agriculture, plant growth regulators are used to increase crop yields, the role of which is to control and accelerate plant life processes, increase stress resistance and stimulate their development. The study investigated substances in a number of derivatives of pyrazolopyridines as regulators of soybean plant growth. For this purpose, a series of new compounds of this class was synthesized and bioscreening was carried out in first laboratory, then field small-scale experiments. Field experiments were conducted at the experimental field of the Kuban State Agricultural University named after I.T. Trublin using soybean crops of the Slavia variety. Vegetative soybean plants were treated with an aqueous solution of a growth regulator twice: in the 4–5 leaf phase and in the budding–branching phase. According to the experimental data, the use of potential growth regulators Ia, If and Ih allowed to increase crop yields by 12.0, 18.0 and 15.4%, respectively, in comparison with untreated plants. At the same time, the number of beans, the number and weight of seeds per plant, as well as the weight of 1000 seeds increased. The grain quality improved: the protein content increased by 0.7–2.2%, and the oil content increased by 0.5–2.4% relative to the control. Under the influence of growth regulators, the photosynthetic activity of plants increased: the content of chlorophyll a in the treated plants was higher than in the control variant by 7–15% throughout the growing season, and chlorophyll b by 6–25%.

The biological effectiveness of modern herbicides in controlling weeds in soybean crops under irrigation in the north of the Astrakhan region has been determined. Field experiments were conducted during 2022–2024 at the experimental irrigated land use site of the PAFSC RAS. The objects of the study were soybean varieties of domestic selection Volgogradka 1 and Aurora. The effectiveness of herbicides in the application of a soybean crop protection system against annual cereal and annual dicotyledonous weeds aimed at the formation of highly productive marketable products was studied. A comparative analysis of the use of selective herbicides based on the active substance metribuzine (Lazurit, SP) and metolachlor (Simba, KE) was carried out in order to identify the most promising option. A high biological efficiency (63.9%) of the soil herbicide Lazurit was established 30 days after its application, with the number of weeds in the control of 26 specimens/m². On the 50^th day after treatment, the decrease in the number of weeds was 59.9% with the number of weeds of 38 specimens/m². The use of this herbicide led to a significant reduction in the number of weeds, which further affected the development of soybean plants.

In experiments conducted in the Kurgan region for 58 years at the Central Experimental Field, the effect of fertilizers and various types of drought on the yield of spring soft wheat was shown. With prolonged drought during the entire growing season, wheat productivity in crop rotation without fallow and fertilizer decreased to 40% of the grain harvest in humid years, with June drought – up to 71% and July – up to 80%. Fertilizers played a positive role in all types of drought, but their effect during droughts was 2–3 times less than in humid years. The lack of moisture had a stronger effect on the formation of wheat yields in the medium-loamy soil of the Central Experimental field compared with the heavy-loamy soils of the Makushinsky and Shadrinsky fields. In dry years, there was a more noticeable decrease in yield in crops far from fallow compared to the first field after fallow. Fertilizer in drought more often had a positive effect on the laying of grains in the ear than on the number of productive stems and the size of the grain harvest. Among the signs of wheat quality, lack of moisture reduced the weight of 1000 grains, but increased the accumulation of gluten in grain and flour both without fertilizers and against the background of N40P20 application. The dose of N20P20, increasing the yield, had little effect on the quality of wheat grain.

In a long-term (8 years) 10-year field experiment with alternating pea–mustard crops, changes in the pH_KCl were traced in sod-podzolic light loamy soil reclaimed by increasing doses of large (5–7 and 7–10 mm) dolomite particles. It has been shown that the higher the dose of dolomite, the greater the shift in soil pH. Differences in the pH_KCl value of the soil depending on the dose of dolomite application persisted throughout the entire observation period. Liming with dolomite particles had a positive effect on the accumulation of calcium by pea plants already in the year of application. Regardless of the variant, the calcium content in the green mass of peas decreased. Empirical models have been developed that describe the transfer of calcium to pea plants throughout the entire observation period. The average rate of calcium decrease in the soil during the experiment was determined. Clustering of individual experimental variants based on the effect of liming on the accumulation of calcium by plants was carried out.

The review discussed the effectiveness of using selenium nanoparticles (Se NP) in agricultural technologies. Based on the analysis of literature data, the proposed methods of applying Se NP were reviewed, the key mechanisms of action of Se NP on plants were summarized in the context of various activities of these nanoparticles (biostimulating, stress-protective, biofortification, nutraceutical, antioxidant) and the effectiveness of applying Se NP using “traditional” forms of mineral selenium fertilizers – selenate and selenite.