Establishment and persistence of surface-sown and resident grasses using three pasture development methods in relation to three stocking managements

Abstract

The botanical composition of pastures improved by three different methods (viz. fertilizer only; seed and fertilizer; and herbicide, seed and fertilizer), were compared on the Northern Tablelands of New South Wales. After sowing, the pastures were grazed strategically for 6 months before three continuous stocking rate treatments (5.0, 7.5 and 10 Merino wethers/ha) were applied to each treatment. After 3 years, all paddocks were continuously grazed by 10 Merino wethers/ha for a further 4 years. The establishment of sown species was improved by herbicide application and the lowest stocking rate. Of the four species sown, Phalaris aquatica showed the greatest response to herbicide application, while the cover of Phalaris aquatica and Dactylis glornerata increased at the lowest stocking rate. These factors were less critical for Festuca arundinacea and Lolium perenne for which differences in level of cover between improvement methods disappeared within 12 months. The effects of the strategic management treatments were inconsistent. The resident pasture failed to recover from herbicide treatment and cover and growth of most grasses was depressed by the presence of sown grasses even in the absence of herbicide. The proportion of winter-active native species in the pasture increased with increasing stocking rate.