Creation of highly productive single-species and mixed grass stands of reed canary grass in the forest-steppe area of Western Siberia

Long-term studies were carried out in the southern forest-steppe area of the Omsk Region on meadow-chernozem soil. It has been established that legume-grass herbal mixtures including reed canary grass are more productive than single-species crops under the conditions of the southern forest-steppe of Western Siberia. Among the paired grass mixtures, the most productive (6.72 t/ha of dry matter) is alfalfa-reed canary grass, the increase to the control sample amounts to 116%. The inclusion of sweet clover and brome in the composition of grass mixtures allows them to have a more stable productivity over the years: in the first two years thanks to sweet clover, in the subsequent years thanks to brome. However, in mixtures with awnless brome, the legume component is actively displaced. The main yield of grass mixtures in the first two years of life is formed by legumes (71-87%), while in the fourth to fifth years it is formed by true grasses (64-93%). In order to form their yield under the conditions of Siberia, legume-grass herbal mixtures including reed canary grass widely use symbiotic nitrogen (Kf = 0.37-0.58), the consumption of which depends on the biological characteristics of the legume component and its content in the mixture. High-yielding mixtures with a high content of leguminous grasses in their composition, viz. reed canary grass with alfalfa, distinguished themselves for increased nitrogen fixation over the years of grass stalk use. The consumption of atmospheric nitrogen amounts to 127 kg/ha or 18.9 kg/t of dry matter, while Kf is 0.58. Involving up to four-five species in the composition of grass mixtures does not provide an increase in productivity and nitrogen-fixing ability in comparison with paired mixtures.