Comparison of winter-active phalaris with the Australian cultivar under rotational grazing. 2. Dry matter on offer, pasture composition and animal production

Abstract

Composition and amount of pasture on offer and animal productivity are presented from an experiment in which 2 'winter-active' cultivars (Sirosa, Holdfast) and a breeding population (Perla Retainer) of phalaris (Phalaris aquatica L.) bred for rapid growth in autumn and winter were compared with the original cultivar, Australian, under rotational grazing at 15 wethersfha for 3 years at 2 sites near Canberra. A change of cultivar rank in phalaris herbage on offer occurred in winter of the second year, whereby Australian became the highest ranked cultivar, reflecting its 50-70% higher basal area and 70% higher tiller density. However, pastures of the winter-active lines had an average 30% more phalaris on offer per unit basal area and per tiller, and a larger component of other, mainly annual, grass. This resulted in total pasture on offer at least equivalent to that of Australian pastures, and possibly more herbage production in autumn and winter. Sheep on the winter-active phalaris pastures were slightly heavier on average due mainly to higher weight gains in the first half of the year. These sheep produced an average over both sites of 7% more wool than sheep on Australian pastures, the advantage being higher at a site with dense phalaris (10%, P<0.01) than at a site with shallow, coarse-textured soil and less phalaris (3.5%, P = 0.11). It was concluded that pastures of the winter-active phalaris lines can give higher wool production than pastures of Australian phalaris, but not necessarily because of higher amounts of phalaris in the pasture. Benefits in the long term would also depend on persistence. Breeders of phalaris should aim to increase yield per unit of basal area if animal production gains in the short term are to be made in this environment, but compromises may be necessary between productivity and long-term persistence.