Key points
- Barley and wheat were sown at two plant populations and two to three sowing dates in spring to assess impact on yield over three consecutive years.
- Barley generally yielded higher than wheat by an average of 30% more on dryland and 19% more under irrigation. These were separate trials but alongside each other.
- For the trials with three sow dates in 2011 and 2012 the early (late August to early September) sowing dates produced the highest yields for both crops with an increase of about 71% for dryland and 34% for irrigated crops over the late sow dates established mid to late October.
- Under irrigation, barley performed just as well at the ‘mid’ sow date (late September) before decreasing by 2.7 t/ha at the late sow date.
- There was a trend for the higher target plant populations (300 plants/m2) to produce higher yields, especially for wheat. In the 2012 season later planted irrigated wheat benefitted by 0.6 t/ha from the higher plant population.
- Barley grain size decreased and screenings increased with delayed drilling particularly on dryland. From sow date 1 to sow date 3 TGW decreased from 44 to 35 g and screenings increased from 8 to 29%.
- The highest gross margins were for the early ($2,050/ha) and mid ($2,015/ha) sow date irrigated barley crops.
- The gross margin was higher for barley than wheat for all sow dates. When the gross margin is divided by the number of days between sowing and harvest the highest return ($14/ha/day) is for irrigated barley sown in the mid timing at the end of September