The impact of the season in which cereals are sown on the diversity of the arable weed flora in rotational fields in Denmark
This study is summarised as evidence for the following.
Plant crops in spring rather than autumnAction Link
Plant crops in spring rather than autumn
A replicated site comparison study in 1988-1992 in 19 arable fields in Denmark (Hald 1999) found that weed diversity in unsprayed crop margins was over 25% lower in winter cereals than in spring cereals. Of the 114 weed species found, 97 were present in spring cereals compared to 87 in winter cereals. Of the species with known germination seasons, 94% were able to germinate in spring cereals whilst 64% were able to germinate in winter cereals. In addition, important food plants for arthropod herbivores occurred at greater densities and higher relative abundance in spring cereals. Experimental plots were 6 x 20 m, with crop rotation determined by the farmer. Each plot was sampled in spring each year, using 10 permanent 0.1 m circles/plot. Only data from permanently unsprayed plots in fields that supported at least one winter and one spring cereal sample were used in the analysis (72 plots).