Effect of sowing date on the weed infestation of winter wheat a in long-term experiment

Detailed coenological studies were made at four developmental stages during the vegetation period in three sowing date variants in a long-term multifactorial experiment carried out in the Crop Production Institute of Pannon University. Both experimental years had poor rainfall supplies. The Balazs-Ujvarosi scoring method was used to register the extent of weed infestation and how it changed over the vegetation period. Both the wheat grain yield and the level of weed infestation were greatly influenced by the sowing date. Averaged over the two years, the largest volume of weeds was recorded in March. After the wheat started shooting, the weeds were suppressed. The three sowing dates had the greatest effect on weed growth from the stage of initial development to shooting. After late sowing, the smallest number of weeds was observed during this period in both years. By the time the crop matured the level of weed infestation had changed, with the largest number of weeds in the late-sown variant, where the whe...