Efficacy of growth regulators for maize fields

Abstract

At the current stage of agricultural development, it is paramount to introduce advanced technologies for maize cultivation. Special attention is required for the use of modern growth regulators in order to ensure stable increase in grain production. To protect maize from stress factors emerging in unfavorable meteorological conditions of the steppe zone (such as drought, high temperatures, negative impacts of pesticides, diseases, etc.), increasing attention is given to the application such physiologically active compounds as plant-growth regulators (PGRs). The experimental studies were carried out in 2021–2023 on the experimental field of the Dnipro State Agrarian-Economic University. The objective of the study was to identify the efficacies of the plant-growth regulators used in different doses on maize. The highest efficacy in the technology of maize cultivation was achieved by treating the maize plants with humates during the phase of 3–5 leaves. This treatment promoted a stable tendency towards growth, resulting in 5–7 cm increase in height (2.1–2.8%), 5–6% increase in leaf surface area, and increases in yield structure (13.6 cm in the cob length (5.1%), 18 grains (3.9%) in cob grain filling, and 29 g (9.1%) in mass of 1,000 grains), compared with the control without growth regulators. Somewhat lower efficiency according to all the aforementioned parameters was demonstrated by coating of seeds. Treatment of the seeds with growth regulators and microbial fertilizers in the phase of 3–5 leaves resulted in 7.3% to 18.7% increase in the yield, indicating their high efficacy, especially in unfavorable weather conditions. Therefore, the greatest gains in the grain yield was seen after using humate 400 g/ha + polyethylene glycol 360 g/ha – 1.08 t/ha; humate 800 g/ha + polyethylene glycol 240 g/ha – 1.19 t/ha; sodium metasilicate 600 g/ha – 1.23 t/ha; Pakt 500 g/ha – 1.23 t/ha; and Peram 100 mL/ha + Vympel PGR 500 g/ha – 1.12 t/ha. That is, of the sixty seven tested combinations of physiologically active compounds, no variant produced a grain-yield increase lower than 0.5 t/ha, and the variants with foliar feeding of the maize demonstrated no clear upward tendency in the yield after the PGRs had been introduced in doses above the norms. Studies of efficiency of the growth regulators and microbial fertilizers for maize confirmed that achievement of maximum grain yield is possible only by optimizing the vital factors at all stages of organogenesis of maize. When climatic elements develop with various amplitudes during a vegetative period, effectiveness of preparations is determined by their ability to enhance tolerance to the environmental stressors.