The effect of biofertilizer on water regime, intensity of photosynthesis and productivity of grain crops in the Steppe Pre-Urals

Grain crops are of great food value, productivity of which largely depends on the water regime and assimilation activity of plants. The purpose of the current study was to determine the effect of biofertilizer on the parameters of the water regime, pigment, and gas composition of grain crops. The study was conducted at the stationary research site of the Botanical Garden of Orenburg State University in 2021–2023. The objects of the research were the spring barley variety Anna, the spring common wheat variety Orenburgskaya Yubileinaya and the spring durum wheat variety Orenburgskaya. The experiment was carried out using biofertilizer containing fermented food residues and crushed plant waste with B. Subtilis bacteria immobilized on their surface. The water regime parameters were studied according to the method of N.N. Kozhushko. Photometric diagnostics was carried out using a portable N-tester device (model PRAK 431155.022, manufactured by Agrotester LLC, Russia). The CO2 content was measured with a portable gas analyzer CI-340 (“CI-340 Hand-held Photosynthesis System”, manufactured by CID Bio-Science, USA). Statistical data processing was performed using the program Statistica 10.0. Based on the study results of the studies, there was found similar dynamics of the decrease in total water content and transpiration intensity for the studied plants at the end of the vegetation period. There has been established a water deficit increase of grain crops in milk stage and its reliable decrease in the biomass of spring common wheat and barley when using biofertilizers in comparison with the control variants. The maximum value of the pair correlation coefficient was established between the parameters of carbon dioxide content and transpiration intensity in common wheat and barley. As for nitrogen in leaves, there has been found a relative constancy of the indices in the samples when using biofertilizer. In contrast, the control samples have shown variability of this trait. There has been identified a positive effect of biofertilizers on the parameters of the water regime of the grain crops, as well as the intensification of photosynthetic activity when using this ameliorant, which improved productivity of the studied grain crops by 147.1 % for barley, and by 105.7 % for common wheat.