Agronomic potential of native grass species on the Northern Tablelands of New South Wales. I. Growth and herbage production

Abstract

The herbage mass and relative growth rate of six perennial native grasses were compared with two introduced temperate perennial grasses (Phalaris aquatica L. cv. Sirosa, Festuca arundinacea Schreb. cv. Demeter and the temperate legume, white clover (Trifolium repens L. cv. Haifa). Of the native grasses three were year-long green species (Danthonia linkii Kunth, Microlaena stipoides (Labill) R.Br., Poa seiberana Spreng), and three were summer-growing frost susceptible species (Themeda australia (R.Br.) Stapf, Sporobolus elongatus R. Br., Bothriochloa macra (Steud) S.T. Blake). The summer perennial species, in particular Bothriochloa, were highly productive. However, in addition to inability to produce or retain green herbage during the winter, the summer-growing perennials produced a lower proportion of leaf material, a feature likely to render them less acceptable for grazing. Themeda was an exception, and produced a high proportion of leaf throughout the growing season and retained green material longer into the winter. Among the yearlong green species, both native and introduced, Poa proved a most productive species with significantly higher green leaf production than any other species, both in terms of herbage mass and relative growth rate. Although Danthonia produced as much herbage as phalaris on an annual basis, it has a higher stem component overall, and its relative growth rate was higher in the warmer months and lower during the winter months. Only Poa, white clover and phalaris produced signficant amounts of herbage during the winter months. These data suggest that native species have valuable agronomic features which could be exploited by selection and plant breeding programmes to advantage by the grazing industry.