Factors, influencing the contamination of spring wheat in the northern forest-steppe of the Southern Urals

The study was conducted to determine the effect of predecessor, mineral fertilizers and weather conditions on the formation of agrophytocenosis of spring wheat using zero tillage technology. The object of the study is the weed component of agrophytocenoses and the activity of its influence on the productivity of spring wheat in the northern forest-steppe zone of the Southern Urals against the background of zero tillage technology. The experimental design was implemented in 3 crop rotation variants and a monoculture, with 6 predecessors of spring wheat, against two fertilization backgrounds: without fertilizers (0) and with the application of nitrogen fertilizers (N). With zero tillage technology, the litter component in spring wheat crops consisted of juvenile weeds in all experimental variants. Their number during sowing according to crop rotation variants significantly depended on the weather conditions of the year, in a waterlogged year, on average, the difference reached 27 units/m², with a coefficient of variation of 47 %. The biomass of spring wheat was significantly dependent on the background of fertilization – on average, the differences over the years reached 72 g/m². According to the predecessor of spring wheat, peas + oats, a higher mass of juvenile weeds was noted, compared with other predecessors, on average by 43…66 g/m² in fertilization backgrounds. The specific mass of weeds significantly depended on the meteorological conditions of the year, with differences reaching 7 %. In dry years, the share of the influence of the number of annual weeds and the biomass of the crop on the productivity of spring wheat on a fertilized background reached 80–82 %.