WINTER FEED PRODUCTION AND GRAIN-YIELD IN MIXTURES OF SPRING AND WINTER WHEATS

The possibility of combining the early rapid growth of extreme spring (express) wheat cultivars with the high grain-producing ability of long-season types as a dual-purpose crop (fodder and grain) for the high-rainfall zone of E. Australia was investigated in an experiment at Canberra in 1985. Mixtures of cv. Sunset, an express wheat, and Isis, a winter wheat, in the proportions of 1:3, 1:1 and 3:1, were compared with 4 long-season and 2 short season wheat cultivars, oats and pastures (Lolium rigidum/Trifolium subterraneum with and without N fertilizer), all sown at the end of summer. Cereals and pastures were cut monthly from 3 different starting dates. Cereals were cut until their developing ears were above ground, and pastures were cut until the trial ended in Nov. In a 4th treatment, cereals were left uncut. An early start to cutting allowed all long-season wheats to be harvested several times for fodder, but in general the total amount harvested was greatest from the latest initial cutting date treatment. The greatest amount of DM harvested (9 t/ha) came from the express wheat Sunset and from Sunset/Isis mixtures, 2 t/ha more than from Isis alone. As well as producing considerably greater amounts of DM during winter, the Sunset/Isis mixtures yielded as much grain (3.4 t/ha from the latest initial cutting date treatment) as Isis alone. DM and grain yields of mixtures were stable across the range of ratios used. It was concluded that grazing of crops sown for winter feed in cool environments should be delayed as long as possible without endangering ears, thereby providing max. amounts of fodder and effectively smothering weeds. Under this regime, mixtures of express and winter wheats should provide at least as much feed as a pasture treated similarly. If cutting started early, both would be less productive, and the crop could be inferior to the pasture. © 1990 CSIRO. All Rights Reserved.