Stubble retention across the farms of central western NSW has become common practice for local farmers. The 2013 CWFS farmer survey (47 farmers covering 207,000 ha) highlighted that 70% of the producers regularly maintained stubble cover over the summer period, while the remaining 20% maintained their fallows by cultivation alone. Canola is one of the most commonly used break crops in central western NSW where wheat is the primary crop grown. Some canola establishment issues under wheat stubble’s in the local area has identified a need for research into this issue.
It is widely accepted that there are 3 concurrent triggers for profitable Canola production in the region.
- A profitable market price
- Good stored sub soil moisture
- Sowing rainfall in April
Trial Design
During the year of 2013 the trial was conducted at three locations- Rankin Springs, Wirrinya and Tullamore.
The trials aimed to investigate the impact the different stubble treatments imposed towards the end of the fallow have on the establishment and yield of canola.
Image sourced from Trial report
The trial was made up of four ranges and four rows with four replicates. The four treatments were standing, burnt, mulched and cultivated stubble. The plot size was 10 meters wide by 40 meters long, running between the co-operators tram tracks. The plots were sown by the farmer as part of their commercial canola planting program.
Yield Summary
There was a significant yield difference between the various stubble treatments. At Wirrinya the burnt and cultivated treatments with yields of (2.55 t/ha) and (2.19 t/ha) respectively yielded significantly higher than the mulched 1.68 t/ha.
At Rankins Springs the burnt and cultivated treatments with yields of (1.23 t/ha) and (1.2 t/ha) respectively yielded significantly higher than the mulched treatment (1.02 t/ha) and standing (1.02 t/ha) treatments.
Key points to take home
- During 2013, The canola crops that were sown on time and met target plant populations it appeared that late burning and/or cultivation of the previous crops stubble improved yield.
- The cost of burning stubble’s needs to be considered when making the decision to burn. Burning stubbles may have a fit in paddocks where windrows are being burnt for weed seed control or stubble’s are to heavy for seeders to get through.
- The cost of cultivation needs to account for both the cost of the operation as well as the risk of soil erosion. The risk of producing a drier seed bed at sowing time should also be considered.
If you would like access to the full trial report feel free to click the link below. If you have any questions regarding the trial feel free to call John Small on 02 6895 1001 or send through an email at john.small@dpi.nsw.gov.au.
