Yield of early dryland sowing of wheat with winter and spring habit in southern and central New South Wales

Abstract

The effect on yield of early sowing of wheat, and of sowing wheats with winter habit, was assessed from routine trials from 29 sites in south and central New South Wales from 1981 to 1990. Early-sown trials were largely sown from mid to late April and conventionally late trials from mid to late May. Entries in early trials consisted of winter wheats or photoperiod-sensitive spring wheats, while photoperiod-insensitive spring wheats were sown in late trials. There was a gradual change in trial entries over the period of study. Although more variable than the late-sown trials, the early-sown trials had high yields over a wider range of sowing times and displayed less risk of frost damage. On average, winter wheats had a 6% yield advantage over late-maturing spring wheats in early-sown trials. Trials yielded 15% more when sown early than late. In comparison with quick-maturing spring wheats, winter wheats did not appear to suffer a large yield penalty when sown late. Yield of early-sown trials declined with sowing before or after the optimum sowing time of late April. There was a large reduction in yield with sowings earlier than 20 April. Yield of spring wheats declined from early May almost linearly with delay in sowing date.