Extensive canola variety time of sowing research conducted throughout eastern Australia in the past four years aims to better match variety phenology with sowing time. Slow developing varieties yielded consistently best from early sowing, commonly earlier than considered “normal” for many districts. Faster developing varieties did best from later sowing, but also a little earlier than often considered “normal”.
Research was led by Rohan Brill (NSW DPI) and John Kirkegaard (CSIRO). Funding included GRDC, NSW DPI, CSIRO as well as investment from other state agencies.
Rohan Brill, detailing the research results at the recent round of GRDC update seminars, noted that despite the very dry and frosty 2017 season, relatively good canola yields occurred alongside poor crops within a given environment and similar rainfall.
However, sowing appropriate varieties for a given sowing time was only one part of the equation for good yields.
There were consistent messages from the crops that were profitable in 2017 Mr Brill noted. Strict fallow weed control that conserved soil moisture from the very wet spring in 2016 was critical. Important commonly also was even straw spread at harvest and prudent stubble grazing management to reduce seedbed moisture loss in autumn, and cover maintained at least until sowing.
Paddock selection with high starting soil water and nitrogen were especially critical for good yields. Hybrid canola varieties showed an advantage but did not alone ensure success. Application of adequate nitrogen to match yield potential was also important.
Matching varietal phenology and sowing date so that flowering starts close to the optimum start of flowering (OSF) date to minimise environmental stresses (frost and high temperatures) was critical (as it is for most grain crops).
There is a period that is most favourable for flowering and reproductive development where the risk of stress (such as frost, heat and drought) is minimised and where resource availability (water and light) is maximised. Research within this project conducted by Julianne Lilley from CSIRO has estimated the ideal OSF dates for canola at various centres.
Examples include Nyngan, July 7, Walgett July 12, Moree July 18, North Star July 22, Hillston July 23, Condobolin July 25, Trangie July 26, Lockhart July 31, Narrabri July 31, Gunnedah August 1, Parkes August 3, Wagga Wagga August 5, Cowra August 6 and Culcairn August 8. In a district paddock elevation differences can alter these dates significantly.
Condobolin 2017 dryland trial data, as an example from early (April 6) sowing, found the slower varieties Archer and ATR Wahoo flowered early August onwards (about ideal despite frosts) whereas fast varieties Nuseed Diamond and ATR Stingray started flowering in late June/early July.
Despite a very dry year early sown slower varieties yielded around 1.0 t/ha from early sowing compared to around 0.3 t/ha from the faster maturing varieties.
In the later sowing (20th April) the reverse was the case with quicker varieties beginning flowering around the ideal time compared to slower ones flowering later and finishing in dry hot conditions. The faster varieties yielded around 0.8 t/ha compared to the slower ones around 0.5 t/ha.
Full details of the research paper will be available on the GRDC website or contact Rohan Brill rohan.brill@dpi.nsw.gov.au. More details also available at: https://grdc.com.au/__data/assets/pdf_file/0015/291012/Ten-Tips-to-Early-Sown-Canola.pdf
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.
