UDC 633.174: 631.8
DOI 10.36461/NP.2025.76.4.022

DURATION OF THE VEGETATION PERIOD AND PHOTOSYNTHETIC PARAMETERS OF SORGHUM DEPENDING ON THE APPLICATION OF FERTILIZERS AND HERBICIDES IN THE DRY STEPPE VOLGA REGION
K. A. Pronudin, Research Officer, A. N. Astashov, Candidate of Agricultural Sciences, Chief Researcher,
V. S. Budarina, Candidate of Agricultural Sciences, Senior Research Officer, A. A. Safronov, Research Officer
Federal State Budgetary Scientific Institution "Russian Research and Design Technological Institute
of Sorghum and Maize", Saratov, Russia, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

A relevant area of research is the development of new approaches to increase the productivity of grain sorghum. The field test conducted was focused on analyzing abiotic factors and growing conditions affecting the progression of development stages and the formation of net photosynthetic productivity in grain sorghum. The experimental work was conducted from 2021 to 2023 at the Federal State Budgetary Scientific Institution RosNIISK "Rossorgo". The results show that the use of the studied preparations increased the duration of the vegetation period in the studied varieties. For the Avans variety, the index ranged from 96 to 101 days, with the maximum value of 101 days observed when NPK was applied at sowing and treated with the Aminopelik herbicide. A similar trend was observed in the Granat variety – 103 days with herbicide application, and 101 days when mineral fertilizer was used with the herbicide. Analysis of the leaf surface area showed that growth-stimulating preparations and fertilizers positively affected this parameter. When mineral fertilizers were used together with growth-stimulating preparations (NPK (500 kg/ha) + Reasil micro–Hydro Mix (3 l/ha) + Reasil Forte Carb-N-Humic (4 l/ha), the largest formation of leaf surface area was observed in the studied varieties: Avans variety – 31.24 thousand m²/ha, Granat variety – 28.4 thousand m²/ha. The use of the herbicide led to a decrease in the leaf surface area of sorghum plants: Avans variety – 25.98 thousand m²/ha, Granat variety – 23.27 thousand m²/ha. The photosynthetic activity of the plants also varied significantly depending on the agricultural techniques used. When NPK mineral fertilizer (500 kg/ha) and the growth-stimulating preparations (Reasil micro–Hydro Mix + Reasil Forte Carb-N-Humic) were applied, the maximum values of photosynthetic potential were observed: Avans variety – 1.29 thousand m²·day/ha, Granat variety – 1.17 thousand m²·day/ha. Overall, the research results demonstrate the high efficiency of the integrated use of agrochemical preparations.
Keywords: agrochemicals, grain sorghum, vegetation period, plant biomass, photosynthetic potential, net photosynthetic productivity.

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