Details are given on the production and survival over four years of five perennial grasses under rotational sheep-grazing on a pumice soil. The comparison involved three perennial ryegrasses ('Grasslands Nui and Ruanui', and Yates Ellett), and mixtures of Ellett with 'Grasslands Roa' tall fescue and Ellett with 'Grasslands Maru' phalaris. All pastures were sown with white and red clovers. Annual dry matter yields from Nui and Ellett pastures were similar, at about 6,500 kg/ha. Ruanui pastures were on average 600 kg/ha lower. The pastures containing tall fescue and phalaris were similar to Ellett. The major seasonal yield effects were in autumn and winter, when Ruanui pastures were substantially poorer than those with Nui and Ellett. Ryegrass yield of Ellett pasture was greater than Nui, and Nui was greater than Ruanui at all seasons. Ellett ryagrass was a higher proportion of the total yield at all times, and had higher tiller populations than Nui and Ruanui. Neither tall fescue or phalaris were, able to compete with Ellett ryegrass. It is suggested that neither of these be sown with ryegrass. Clover yields were higher in Ruanui than Ellett pastures, with Nui intermediate. The use of Nui, Ellett and Ruanui ryegrasses is related to the problems of seasonal distribution and total annual yields of pastures on the Central Plateau. It is suggested using Nui or Ellett as the base for perennial pastures will give substantial increases in production. Ellett ryegrass had higher survival than Nui which was considered an advantage, though this was achieved at the expense of a small reduction in clover vields. Keywords: Perennial ryegrass, Ellett, Nui, Ruanui, Roa tall fescue, Maru phalaris, canary grass, sheep grazing, central North Island, Central Plateau, grass grub, Argentine stem weevil, Lolium endophyte.
Aetiology and epidemiology of viral croup in Glasgow, 1966–72
