Effects of competition, herbicides and activated carbon on establishment of Australian grasses

Abstract

Summary:The establishment of four Australian native grasses, Themeda australis (R.Br) Stapf, Bothriochloa macra (Steud) S.T. Blake, Danthonia spp. and Stipa bigeniculata Hughes, was investigated in a weedy soil under glasshouse conditions at Canberra, Australia. The presence of weeds (approximately 3500/m2) significantly reduced the percentage emergence of Danthonia and Stipa but had no effect on Themeda, Bothriochloa or the pasture species Lolium perenne L. (ryegrass). The percentage reduction in dry matter production after 8 weeks in the presence of weeds was less for Themeda and Bothriochloa (65%) than for Stipa and ryegrass (80%), while Danthonia production was reduced by over 90% Chlorthal‐dimethyl at 6 or 12 kg/ha reduced the number of emerged seedlings of Danthonia and Stipa but had no effect on emergence of Themeda and Bothriochloa. Diuron at 4 and 16 kg/ha was toxic to seedlings of all four species. The application of activated carbon as a band or a seed pellet overcame the toxic effects of both herbicides, at least at the lower rates of application. The results are discussed in relation to the establishment of native grasses on urban areas requiring low maintenance.