As with wheat and barley, research is showing that earlier sowing time than previously considered feasible is relevant to canola, provided slower-maturing varieties are used.
While early canola sowing, such as late March early April, is not always the highest yield, it commonly is or is close to highest yield.
More importantly, early sowing in some years is possible where later sowing conditions may be too dry or too wet and early sowing helps spread the sowing workload with no long-term yield penalty likely.
NSW DPI agronomists Rohan Brill, Ian Menz, Rick Graham, Leigh Jenkins, Kathi Hertel, Don McCaffery and Colin McMaster, with CSIRO researchers John Kirkegaard and Julianne Lilley, are conducting the NSW arm of a national canola research study funded by the Grains Research and Development Corporation.
Wagga Wagga (eastern Riverina), Ganmain (north-eastern Riverina), Condobolin (Central West plains), Canowindra (CW Slopes), Trangie (CW Plains), Narrabri (North West plains) and Breeza (Liverpool Plains) are the sites of the NSW research.
A strong focus of the research has been investigating interactions between sowing date and canola variety choice.
At Wagga Wagga in 2016, long-season varieties such as Archer, GT50 RR and Hyola 600RR maintained consistent grain yield across sowing dates March 31, April 13 and April 29.
The highest individual treatment yield was quick maturing Nuseed Diamond sown on 29 April, yielding 4.8 tonnes to the hectare.
Fast developing varieties yielded less from early sowing, partly because flowering occurred too early to maximise biomass and seed number.
In addition increased disease infection (despite multiple applications of fungicide) was common from early sown fast developing varieties.
Very early flowering (June) of these varieties exposed them to infection events all through winter, with sclerotinia and upper canopy blackleg infection an issue in some varieties.
Breeza with deep clay soils was the only site where yield was similar from all sowing times, in this sites case April 13, May 16 and June 17 (the only site with June sowing).
Condobolin, Ganmain and Trangie had similar trends to the Wagga Wagga results.
The research has demonstrated that there are some varieties that have a wide planting window, allowing sowing opportunities to be captured when they arise, and that can often match the yields of later-sown varieties. In contrast, fast-developing varieties often only preform near best or best when planted in the later sowing window to avoid reduced grain yield potential and increased disease risk.
Rohan Brill also reports that the 2016 research reinforces the importance of adequate nitrogen for canola.
The best variety choice and sowing date management without appropriate nitrogen management is a lost opportunity he stresses.
Mr Brill says the research supports that approximately 80 kilograms to the hectare of available nitrogen is required per tonne/ha of targeted grain yield.
With declining levels of soil fertility common, this means nitrogen requirements are being met more and more by fertiliser rather than soil reserves.
Aiming to plant canola in high nitrogen situations will greatly reduce the risk associated with growing canola.
Further details of this ongoing research project are available from 2017 GRDC cropping updates or phone Rohan Brill on 02 6938 1989 or email to rohan.brill@dpi.nsw.gov.au
Next week. Perennial grass establishment success improved with early sowing and planning.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.