Grains Research and Development Corporation (GRDC) funding is helping challenge the boundaries of sorghum production on the Liverpool Plains in northern New South Wales.
While sorghum is reliably grown in the medium-to-high-rainfall zone of the northern region, crop modelling suggests yields could be falling short of their potential.
GRDC Northern Region Panellist Loretta Serafin, Leader Northern Dryland Cropping Systems, NSW Department of Primary Industries.
Over the past three years GRDC supported research conducted by the New South Wales Department of Primary Industries (DPI), has delved into the question of `why’ by examining the impact of plant population, row configuration, phosphorus and nitrogen (N) applications, hybrid selection and time of sowing on grain yield.
Several trial sites have been established and monitored including Breeza and either Premer, Pine Ridge or Willow Tree depending on the season.
Some clear results and recommendations have been generated from the Breeza trial over the past two years (2013/14 and 2014/15) which sorghum growers can use to help guide their future decision making on agronomic management.
Sowing in the “ideal window” at the end of October/early November generated higher yields than the late sowing in December. In the 2013/14 season, the early sowing yielded 0.25 tonnes/hectare higher than the later planted crop.
Three hybrids were utilised, MR Buster, MR Scorpio and 85G33, with MR Buster included as a commercial check and the two other varieties as examples of recent release hybrids.
Yield differences due to hybrid selection were small, with much larger yield differences resulting from varying crop nitrogen nutrition, row spacing, sowing time and plant density.
There was a noticeable response to N in the trials, with yield increasing in line with increases in the N rate at both times of sowing.
In the earlier sown crops, the use of 200kg N compared to nil nitrogen resulted in an additional 1.81 t/ha grain yield while in the late sown trials it resulted in an increase of 0.85 t/ha.
There was also a 1 t/ha increase in yield with the October plant as plant population increased from 50,000 to 75,000 plants/ha (3.01 t/ha versus 4.10 t/ha).
However, there was no difference in yield between the 75,000 and 100,000 plants/ha treatments (4.1 t/ha and 4.17 t/ha). At the same time there was no significant response to varying population in the late sowing treatment (average yield 3.3 t/ha).
At the end of the day, it’s no secret that yield is the big driver for profitability in grain sorghum and more informed agronomic management is imperative if we are to continue pushing the bar on current yield benchmarks.
Sarah Jeffrey, Senior Consultant Cox Inall Communications
0418 152 859
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