Timing is critical when it comes to windrowing canola to maximise yield and now there is a new guide to help growers determine the optimal time for action.
Developed as part of the Optimised Canola Profitability (OCP) Project the Canola: Windrow on time, reap the rewards guidelines bring together five years of research from across eastern Australia to provide growers, agronomists and farm advisers with critical insights into harvest management.
The OCP project was an investment collaboration between the Grains Research and Development Corporation (GRDC), CSIRO Agriculture and Food and the New South Wales Department of Primary Industries (NSW DPI).
GRDC Grower Relations Manager – North, Graeme Sandral, says the new guidelines were designed to support grower decision making and minimise losses from poor windrow timing.
“The new optimum timing for windrowing canola crops is 60 to 80 per cent seed colour change with pod samples taken from the middle third of the main stem and branches,” Mr Sandral says.
“Seed colour change (SCC) on the branches starts later than on the main stem, so relying solely on the main stem for windrowing decisions will underestimate seed colour change across the whole plant.
“This is important when you consider that branches can contribute in excess of 70 per cent of canola yield potential.
“Relying solely on seed colour change from the primary stem could result in smaller seed size, lower yield and oil concentration.”
NSW DPI Technical Specialist, Don McCaffery says the new guide also emphasised the importance of treating all canola varieties the same way.
“Research has found the SCC rule applies across all varieties. SCC is when a minimum of two-thirds of the surface of an individual seed has changed colour from green to red, brown or black,” Mr McCaffery says.
“Growers also need to carefully consider where they collect samples within a paddock.
“Crop maturity within a paddock is affected by factors such as topography, soil type, crop nutrition and plant population. Both the least mature and most mature parts of the paddock need to be considered and assessed when determining windrow timing.”
But Mr McCaffery says the regional location of the farm would also have an impact on the speed of maturity and seed colour change.
Research has shown the rate of seed colour change in southern NSW was typically estimated at five per cent per day, while in northern NSW and Queensland it was closer to 10 per cent a day.
However, Mr Sandral says the rate of seed colour change would vary with seasonal conditions, so regular checks of seed development were very important.
He said the following approximations were useful when considering windrowing logistics over the farm.
For example, a five per cent a day seed colour change provides five days of windowing if you start at 60 per cent colour change (less than 5 per cent windrow timing yield losses) and finish at 75 per cent colour change (approximately zero per cent windrow timing yield losses).
“This approach provides an average estimated one to two per cent windrow timing yield loss over the five-day windrowing program,” he says.
“In practice it can be challenging to windrow large areas at the optimum time so there will always be some compromises.”
Hard copies of the ‘Canola: Windrow on time, reap the rewards’ guidelines are available and come with a paddle to assist growers identify SCC percentages. For a hard copy kit please contact NSW DPI’s Danielle Malcolm on 0429 171 337. There is a limit of 20 kits for commercial agronomists and 1-2 kits for canola growers.