H. OSTROWSKI and J.C. MULDER

Abstract

Setaria sphacelata var. sericea cv. Narok has considerable potential as a grass for autumn deferment to provide winter grazing in coastal south-east Queensland. The effect of successive times of withdrawal of Narok pastures from grazing during autumn and early spring periods on yields of dry matter and leaf, N and P content, and in vitro digestibility percentage was measured under varying rates of nitrogen fertiliser.
High dry, matter yields (c. 8000 kg ha^-1) can be, held over during winter (June and July.) from autumn, saved pastures of Narok fertilised with 100 kg N ha^-1. The quality of pasture saved for deferred grazing deteriorates with time. For maximum dry matter yields these pastures should be, closed in early March. For the highest leaf nitrogen yields available for grazing in June and early July, pastures should be closed in late March. Pastures closed as late as April 10 can produce about 3000 kg ha^-1 dry matter by the end of July.
Growth of Narok in early spring under average rainfall conditions is slow and this grass is usually unable to produce high yields before mid-November. In a wet spring, however, Narok can, produce high yields (c. 4700 kg ha) by the end of October.