Optimization of timing of herbicide treatment of emmer crops in the southern forest-steppe of the Omsk oblasti

Data from studies in the southern forest-steppe of the Omsk region on meadow-chernozem medium-deep low-humus medium-loamy soil for 2021-2023 are presented to determine the optimal period of treatment with the herbicide Puma Plus at a rate of 1.4 l/ha for emmer crops of the Runo variety. Working fluid consumption 200 l/ha. Sowing time is the first ten days of May. The experiment was repeated five times, the plot area was 60 m2. The predecessor was spring wheat in black fallow without herbicide treatment. Three treatment periods were tested: when 2-3 emmer leaves are formed, during tillering and when 2-3 nodes are formed on the emmer stems. In 2021 and 2022 the optimal processing period was the tillering phase. The proportion of weeds was minimal against the unfertilized background - 3.54-3.57% and against the background of ammophos (N12P52) added during sowing - 4.13-4.54%. Accordingly, the maximum grain yield was formed here - 2.55-2.57 and 2.67-2.69 t/ha. A peculiar situation has emerged in 2023. After heavy rainfall a week after the last treatment period, the share of weeds here was 13.28-14.16%, mainly due to white pigweed and acorn grass. With earlier treatment, the proportion of weeds exceeded 20%. As a result, grain yield here was 0.90-0.91 and 1.24-1.26 t/ha. Under normal weather conditions for the zone, the best option was to treat the crops with a herbicide during the emmer tillering phase. All years of experience, there was an increase in weediness of crops against the background of pre-sowing application of ammophos, which was not always compensated by an increase in spelled grain yield.