Agrophytocenosis contamination and of spring wheat productivity in the Omsk region forest-steppe

The purpose of the study is to identify agro-ecological features of the influence of tillage and means of intensification in the grain-fallow crop rotation for non-fallow (grain) predecessors on the infestation of agrophytocenosis and the yield of spring wheat in the forest-steppe of the Omsk Region. Studies in a long-term stationary crop rotation have established that the degree and species composition of the weed component in spring wheat crops in forest-steppe agrolandscapes is formed and is largely determined by the agricultural technology of cultivation. Agrophytocenoses with increased infestation, both in terms of numbers and biomass, are formed on minimal tillage and re-sowing of spring wheat due to increased competition for water and nutrient resources. The most favorable conditions for the formation of a productive agrophytocenosis are formed with complex chemicalization, which helps to reduce the number and biomass of the weed component by 3.6-3.9 times, mainly due to the suppression of bluegrass weeds. The relationship between the productivity of spring wheat and the weediness of crops has a negative direction - up to 48-53 %, and with bluegrass reaches 64-90 %. It was revealed that the minimization of the cultivation of chernozem soils and repeated crops of spring wheat led to a decrease in the productivity of crops. The decrease in the effectiveness of minimal methods of tillage, especially with the limited use of chemicals, is due to a decrease in biological activity and nutritional regime, deterioration of the phytosanitary state, and an increase in the weediness of agrophytocenosis. The increase in the yield of spring wheat grain with the systematic (more than 15 years) use of herbicides (dicoticides + graminicides) in the grain fallow crop rotation reaches 0.44-0.60 t/ha (26-58 %).