Influence of growth regulators on photosynthetic activity of spring barley crops
The use of growth regulators in crop production, along with other agrotechnical methods of intensive and biologized technologies of cultivation, is one of the most appropriate and promising methods of increasing the productivity of crops. In this regard, the purpose of our research was to study the effect of growth regulators used at tillering stage on the photosynthetic activity of spring barley crops in the taiga-forest zone. To achieve this goal it was necessary to solve the following tasks: to determine the duration of the main phases of development and the growing season of spring barley; determine the leaf area of crops, the accumulation of dry matter, calculate parametres of photosynthetic potential and net productivity of photosynthesis of crops during the main phases of development. Investigations were carried out in the Republic of Mari El on sod-podzolic soil by field trial and laboratory analysis using appropriate methods. Spring barley plants they were sprayed with Epin-Extra, Zircon and Polistin at the tillering stage. As a result of the research, it was established that spraying of crops in the tillering stage with the growth regulators Epin-Extra, Zircon and Polistin shortens the vegetation period by 2-4 days in the taiga-forest zone in cultivation of spring barley on sod-podzolic soil; the growth regulators Epin-Extra and Polistin increase assimilation surface of crop leaves by 8,5 and 11,1 %, respectively, the photosynthetic potential - by 5,7 % and the net productivity of photosynthesis by 3 and 10 %; Zircon growth regulator does not have a positive effect on photosynthetic activity of spring barley crops in the soil and climatic conditions of the Republic of Mari El.