The effect of herbicide and fertiliser rate on weed productivity in spring wheat.

Abstract

A trial was conducted within a commercial crop of autumn sown spring wheat involving four rates of nitrogen (0, 40, 80 & l60kgN/ha) with and without the use of herbicide. The weed population was monitored throughout the season for species composition, density, above-ground dry weight and seed production. Total weed dry weight per plot was found to be positively correlated with increasing nitrogen rate up until the final weed harvest. Species dry weights and reproductive output were generally found to be higher on the fertilised plots . The main weed species present were Viola arvensis, Papaver rhoeas, Veronica persica and Veronica arvensis. The use of herbicide suppressed weed seed numbers and dry weight production on all plots, but the response differed between individual species . Reduced input systems would increase the reproductive potential of some species over others and this will have implications for weed seed return, future infestations and management.