The after-effect of long-term reduced tillage systems on the biodiversity of weeds in spring crops

A strictly controlled field experiment on traditional and reduced tillage systems as well as herbicide treatment was con-ducted at the Agricultural Experimental Station of Uhrusk in the years 2007-2011. In the last year of the experiment, the effect of different tillage systems on the level of weed infestation and biodiversity of weeds was determined in all the plots for the crop of common spring wheat Triticum aestivum L., spring du-rum wheat Triticum durum Desf., and oat Avena sativa L. at two growth stages: tillering (23/24 on BBCH scale) and dough stage (83/85). A higher number and higher air-dry weight of weeds were determined at tillering than at the dough stage. Long-term reduced tillage increased the number of weeds per 1m2 at the tillering stage, contrary to herbicide treatment. At the dough stage, a higher number of weeds was observed in the herbicide treatment and reduced tillage plots compared to traditional til-lage. The air-dry weight of weeds at the tillering and dough sta-ges of cereals was significantly higher in the case of herbicide treatment than under the traditional and reduced tillage systems. Weed communities in spring wheat, durum wheat and oat inclu-ded mostly annual weeds. A higher number of weed species was determined in the plot with long-term herbicide treatment than in the plots with reduced and traditional tillage systems. Key words: spring wheat, durum wheat, oat, plough tillage, ploughless tillage, herbicide treatment, number of weeds, air-dry weight of weeds, weed species compositio