Establishment of legumes and grasses overdrilled into Hieracium ‐infested montane tussock grasslands

Abstract

The establishment of lotus (Lotus corniculatus), alsike clover (Trifolium hybridum), cocksfoot (Dactylis glomerata), and mountain brome (Bromus marginatus) were compared following overdrilling by an experimental strip seeder and a conventional triple disc drill in the presence and absence of paraquat herbicide. Drilling was carried out in late August or in late January at two sites on dry, undeveloped soils in the Mackenzie Basin, New Zealand. With August sowing, the number of lotus, cocksfoot, and brome, but not alsike seedlings at the end of the first growing season, were higher with the strip seeder drill than with the triple disc drill. With January sowing, lotus, alsike, and cocksfoot seedling numbers were higher with the strip seeder drill. Numbers declined over the following four years but the advantage of the strip seeder drill remained. Improved seedling nodulation, root development, root length, and shoot length were recorded with the strip seeder drill. Drill effects on legume herbage accumulation in Years 2–4 were not consistent. There were no significant herbicide effects on seedling establishment in the first growing season but herbicide increased legume herbage accumulation in Years 2–4, particularly with the triple disc drill. The higher seedling establishment and enhanced early seedling growth indicate the potential of the strip seeder drill technology particularly for establishing species with low seedling vigour.