Weed ingress in perennial ryegrass (Lolium perenne) and tall fescue (Schedonorus arundinaceus)based swards under dairy grazing

Abstract

Weed ingress was assessed monthly over four years in a total of six swards of perennial ryegrass (Lolium perenne) or tall fescue (Schedonorus arundinaceus) to which were added a legume (2 species mix) legume and forage herbs (4 species mix) or legumes herbs other grasses (8 species mix) Unsown species (weeds) present were from 13 families of which Asteraceae was the most abundant Asteraceae species increased from <1 to 18 of total basal cover in ryegrassbased swards and from <1 to 14 in tall fescuebased swards over the study period Asteraceae reached 81 of total weed basal cover in perennial ryegrass and 82 in tall fescuebased swards in the final year While the basal cover of total unsown species was lower in perennial ryegrass than tall fescuebased swards in the first three years of the study increasing the number of sown species (from a 2species to an 8species mix) had little effect on the ingress of Asteraceae or other weed species