Establishment, persistence and production of lucerne-perennial grass pastures surface-sown on hill country

Abstract

In a series of experiments on unploughed hill country near Turondale, New South Wales, the effects of rate and type of herbicide on establishment, survival and persistence of surface-sown Medicago sativa, Trifolium subterraneum, Dactylis glomerata and Phalaris tuberosa were ascertained. Measurements of plant density and dry matter production of the pasture under grazing were made for up to seven years after sowing. Establishment was achieved under various rainfall conditions from eleven sowings. Herbicide application proved essential for the establishment and survival of the perennial species. Survival of M. sativa seedlings through their first summer was greater on the 2,2-DPA treatments than on paraquat treatments. The addition of simazine to paraquat increased survival of M. sativa over that on the paraquat-alone treatment. No similar effect was observed when simazine was added to 2,2-DPA. Establishment and survival were not influenced by rates of 2,2-DPA between 4.1 and 12.4 kg a.e. ha-1. Plant density in established swards was increased by up to 1200 per cent by strategic grazing applied after the improved species had completed seeding. Lucerne dominated other species and in the final year of measurement produced 87 per cent of a mean dry matter production of 9719 kg ha-1.