AUTUMN NITROGEN FERTILISER IN A DRYLAND SHEEP SYSTEM

Abstract

Applying 50 kg N/ha to dryland ryegrass-white clover pasture in autumn in each of four years resulted in an increased carrying capacity over the control for the last two years of 137 kg liveweight per ha at minimum in December, with an early spring peak of 211 kg extra liveweight per ha. Despite higher stocking rates on N-treated pastures in the later years. feed on offer at grazing was greater from early winter until the onset of severe drought, typically 8 months later. This improved level of feeding lifted ewe bodyweights post lambing by at least 4 kg. These higher ewe body weights were associated with significantly higher birth weights of twin lambs. Daily growth rates of these lambs. in a flock averagmg better than 175% lambing, were in excess of 260 g/head when ewe bodyweights were over 60 kg post lambing. Keywords: Nitrogen fertiliser, sheep grazing, lamb growth rates