The experiment was conducted in the Nyírlugos experimental field of Institute for Soil Science and Agricultural Chemistry. The long-term experiment was set up in 1962 to study the effect of various agronomic interventions on acid sandy brown forest soil typical of the region. In this area, the effects of different levels of nutrient supply have been examined in triticale monoculture since 1991. The upper layer of sandy soil quickly loses its water content due to its physical properties, and this may possibly result in special weed composition.

We studied the effect of different fertiliser treatments on the weed flora composition, and density of each species. Examination of the weed cover was performed in four treatments (N:P:K – 0:0:0, 50:0:0, 150:0:0, 100:120:120 kg ha-1 year-1) with 3 replications taken before harvesting of triticale. In the experiment there was no weed control prior to the survey.

On the examined plots, 13 weed species were found. The annual species were present in more than 95% of the weed cover. Apera spica-venti (L.) P. B. dominated in the control and in the N treatments competing with the cultivated plant. The cover of Ambrosia artemisiifolia L. decreased with increasing N dose, but its cover enlarged several fold in the NK and NPK treatments. With increasing N doses, the cover of Spergula arvensis L. increased, but in the combined treatments it was barely present.

Keywords: long-term fertilisation experiment, nitrogen, triticale, weed cover, weed composition