Influence of weediness and infection of crops on barley yield in the forest-steppe of the Omsk region

The purpose of research is to establish the patterns of formation of weediness in crops depending on agricultural technologies and varietal composition of barley in forest-steppe agricultural landscapes of the Omsk Region. The studies were carried out in a long-term (2006-2021) stationary grain-fallow crop rotation on the trailing crop - barley and short-term experiments. The spring barley varieties Omsky 90, Sasha, and 5 brewing varieties were sown. It has been established that a more weedy agrophytocenosis is formed using extensive agricultural technology with zero tillage (on average up to 620 g/m2 - 44.2 %). With complex chemicalization, the biomass of barley increases by 2 times (from 752 to 1534 g/m2) while the weed component decreases by 4.2 times (from 44.1 to 10.6 %), with a predominance of bluegrass - 81-83 %. The relationship between barley yield and the biomass and number of dicotyledonous weeds is negative (up to 67-81 %). With the integrated use of chemical agents, plant damage by root rot is reduced by 19.8 %, leaf diseases of the upper tier of barley leaves, a decrease in the development of reticulate film - from 20.6 to 11.4 %, helminthosporiosis - from 10.3 to 5.8 %, brown rust - from 5.9 to 1.6 %. With intensive agricultural technology, the winner is resource-saving combined tillage in crop rotation (alternating moldboard and flat-cut) with a yield of 3.40 t/ha, the Beatrice variety - 2.74 t/ha with a protein content of less than 12 %.