POTENTIAL WA canola yields peak on duplex soils from a sowing date close to 1 April and drop off quickly towards an end-of-June sowing, according to research based on 100 years of data.
CSIRO Plant Industry researcher Imma Farre has run a century of weather statistics through state-of-the-art modelling software to help zero-in on the optimum sowing time for canola. Simulation shows that the 100-year average yield fell from 1.6 t/ha when sown at 1 April to 0.6 t/ha at 30 June in Mullewa (short season) and from 2.6 t/ha to 1.9 t/ha at the same dates in Kojonup (long season). Late-sown canola yields drop off by up to 14 kg per ha per day in a short-season environment, or 9 kg per ha per day in a long-season environment.
"Canola is sensitive to water deficiencies during grain filling. So when filling occurs later in the season, as rainfall subsides and soil moisture diminishes, yield suffers and returns can plummet or be lost altogether," Dr Farre said. "Delaying sowing pushes grain filling further into spring and shortens the time from sowing to flowering, which can also reduce yield. In short-season environments, with dry finishes, these effects are more profound."
Program 4 Contact: Dr Imma Farre 08 9333 6789