CHEMICAL MANIPULATION OF HILL COUNTRY PASTURES TO PRODUCE LEGUME DOMINANCE

Abstract

Hill country pasture was sprayed with low fates of the herbicides paraquat, sethoxydim or Dowco 453 in late November. Legume content of the pasture 6 weeks after application increased from 29 to 61%, and from 12 to 31% in January 1983 and 1984 respectively. The chemicals reduced dry matter yields by 16 and 45%, 6 weeks after treatment, but yields were not reduced in subsequent harvests. The chemicals reduced dead matter content, strongly suppressed grass seed head production, increased clover seed head density and increased in vitro digestibility. Sethoxydim at high rates 150 g/ha reduced perennial ryegrass (Lo/km perenne) content, but Dowco 453 increased perennial ryegrass and decreased browntop (Agrosfis tenuis) content. The effect of clover content and dead matter on sheep diet selection is shown and the implications of these results for management of hill country pastures in moist si;m.mers are discussed. Keywords: herbicide, paraquat, sethoxydim, Dowco 453, white clover, Trifolium repens, hill country, in vitro digestibility, perennial ryegrass, Lolium perenne ryegrass, Lolium perenne browntop, Agrostis tenuis.