Establishment, growth and survival of six pasture species surface sown on unploughed land infested with serrated tussock (Nassella trichotoma)

Abstract

The effects of herbicide, inoculation, and nitrogen on establishment, growth and survival of Trifolium pratense, T. repens, T. subterraneum, Lolium perenne, Dactylis glomerata, and Phalaris tuberosa were recorded at Rockley, New South Wales. Seed was surface sown on unploughed land dominated by tussock grass (Nassella trichotoma). All clovers established on unploughed land but only T. subterraneum survived successfully two years after sowing. Establishment of L. perenne and D. glomerata was three to four times as high as P. tuberosa, but two years later there were more P. tuberosa plants than either L. perenne or D. glomerata. Herbicide treatment increased establishment and growth of all grasses and was essential for their survival ; it was not essential for establishment or nodulation of the three clovers nor for regeneration of T. mbterranew, but did have beneficial effects. Nitrogen decreased the establishment of D. glomeratb but increased growth of all grasses and survival of L. perenne and D. glomerata; it depressed the establishment, nodulation, and growth of clovers. Three-step inoculation gave successful nodulation and proved essential for growth of all clovers and regeneration of subterranean clover.