Establishment and growth of grasses overdrilled into clover‐developed, montane tussock grasslands

Abstract

Field experiments on clover‐developed, dry, montane tussock grassland soils compared the establishment of grasses following broadcast oversowing and overdrilling by an experimental strip seeder or a conventional triple disc drill, in the presence or absence of herbicides. Perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata) were used with all three sowing methods. Tall fescue (Festuca arundinaced) and Black Mountain rye (Secale montanum) were used only with the experimental strip seeder drill. Treatments were sown in September‐October 1991. With oversowing, few seedlings established at the end of the first growing season (May) and no seedlings survived the following winter. With overdrilling, nine weeks after sowing there were two times the number of ryegrass seedlings and six times the number of cocksfoot seedlings in treatments sown with the strip seeder compared with those sown with the triple disc drill. Ryegrass seedlings numbers in May were 2‐ to 6‐fold higher and cocksfoot 15‐ to 20‐fold higher with the strip seeder drill compared with the triple disc drill. Ryegrass and cocksfoot seedlings from the strip seeder drill were also larger and had a longer and more extensive root development than those from the triple disc drill. The effects were still evident in Years 2 and 3, when dry matter yields of ryegrass, and cocksfoot in the triple disc treatments remained low even when herbicide had been applied. Yields of ryegrass and cocksfoot in the triple disc treatment with herbicide were similar to yields with the strip seeder drill in the absence of herbicide. The results demonstrate serious limitations when conventional sowing methods are used to establish grasses into clover‐developed tussock grasslands, and indicate the potential of strip seeder drill technology for effective establishment.