As canola growers prepare for harvest, data from three-year trials in southern NSW is demonstrating how irrigated crops can yield more than four tonnes/hectare with careful varietal selection and optimal agronomic management.
Speaking at a recent Grains Research and Development Corporation Update at Yanco, NSW DPI research and development agronomist Tony Napier said the impact of variety selection, agronomic management, nitrogen management, plant population and sowing date was examined in three experiments supported by NSW DPI and GRDC.
‘‘Irrigated canola is becoming increasingly common in crop rotations due to improved varieties and current financial returns relative to other crops,’’ Mr Napier said.
‘‘In all three years we found that variety had a significant effect on canola grain yield,’’ he said.
‘‘In 2016, Pioneer 45Y88 (CL) had the highest average machine harvested yield across the three experiments at 4.30tonne/ha and was the highest individually yielding variety in all experiments.’’
Nuseed Diamond had the second highest average yield (4.05tonne/ha) and was the second highest yield in two experiments, followed by Pioneer 45Y25 (RR) (3.99tonne/ha).
AV-Garnet, Hyola 575CL, Nuseed GT-50, Hyola 600RR and Pioneer 44Y89 (CL) all had an average yield over 3.6tonne/ha.
‘‘Variety selection also had a significant effect on grain oil content, with AV-GarnetA, Pioneer 45Y88 (CL), Hyola 559TT and Nuseed Diamond all achieving the highest average oil content when averaged across these experiments,’’ Mr Napier said.
Results showed the three TT varieties, ATR-Bonito, ATR-Gem and Hyola 559TT were consistently the lowest yielding varieties.
‘‘In the experiments we had no weed control issues. Only consider using the TT varieties if you need them for their better weed control options,’’ Mr Napier said.
Grain yield was also impacted by the nitrogen rate used, with the very low rate of 150kg N/ha base and no top-dressed nitrogen resulting in a significantly lower grain yield (3.46tonne/ha) than the three other rates.
The low, medium and high nitrogen application rates yielded 3.72tonne/ha, 3.85tonne/ha and 3.79tonne/ha respectively and did not differ significantly.
Looking at grain oil content, the sowing date and nitrogen application rate both had a significant effect.
‘‘The later sowing date of April 26 resulted in a significantly higher grain oil content of 46.05 per cent compared with 42.44 per cent for the earlier sowing date of April 5,’’ Mr Napier said.
‘‘All varieties had a higher oil content at the later sowing date but the level of response to sowing date varied between varieties.’’
It was noted that crop lodging was also associated with variety selection, as well as there being a correlation with yield.
‘‘Variety selection significantly affected lodging. Hyola 559TT had the highest average lodging score followed by Hyola 600RR and AV-Garnet which were in the top three most lodged varieties in every experiment,’’ Mr Napier said.
‘‘In terms of yield, the top four yielding varieties had an average lodging score of 1.63 which was lower than the lowest four yielding varieties with an average lodging score of 3.16.’’