STUDY ON COMPETITION BETWEEN MAIZE AND WEEDS IN LONG-TERM SOIL TILLAGE EXPERIMENTS

Our study was carried out at Keszthely, in 2006. The effect of different cultivation methods: no-till drill, disk tillage, conventional tillage (ploughing) and five increasing N doses were studied on the weediness. Samples were taken 4 and 9 weeks after the sowing of maize. For the reason of competition studies no herbicides were applied on sampling sites. For comparison, maize plants from neighbouring herbicide-treated sites were harvested and analyzed. The aerial parts of plants were collected, and the fresh and dry matter weight was measured. We analyzed in detail, the occurrence of weed species, and the biomass production of weeds in comparison with maize. Data obtained from weedy and weed-free control areas were then compared. The effect of different cultivation methods markedly demonstrated the weed cover, the number of perennial and annual weeds and the number of occurring weed species. As a result of crop-weed competition we can establish, that the shoot mass of maize plants was more than 40 % lower on weedy sites than on herbicide treated (weed free) sites. We found that uptake of nutrients in large amounts by weeds at the early stage of the development of maize is an important factor in crop-weed competition.