This project was made possible due to GRDC investment.
Western Australia’s southern cropping regions have a need for further diversification in crop rotations for disease and weed management and for the development of more robust and sustainable farming systems. Current rotations revolve around cereal grains with break crops being heavily reliant on canola. The key objectives of this project were to determine if:
- linseed can be successfully grown under dryland farming conditions in southern WA,
- if any investment is required into machinery and infrastructure by growers to grow linseed,
- to develop basic agronomic guidelines and to assess the yield potential of three commercially available linseed varieties grown under dryland conditions in WA, Croxton, Glenelg and Bilton.
All these outcomes were successfully achieved within the project.
In 2021 the canola and linseed stubbles were tested for soil borne pathogens (PredictaB) and the following crops yields were measured to determine if there was a benefit to the following crop from the potential drop in disease pressure.
Over the three grower demonstration sites there was a considerable drop in nematode pressure and overall soil borne pathogen pressure. P. neglectus and P. quasitereoides disease pressure in particular was reduced from medium to medium to low disease risk down to low to zero disease risk.
The results from the crop yields in the season following the linseed or canola crops were mixed. The PredictaB results certainly demonstrated a reduction in soil borne disease pressure however this didn’t always able to translate into final yield. The Katanning site did demonstrate an advantage in growing lupins after linseed compared to canola however due the very wet season a large portion of the canola area was damaged by water logging which impacted the validity of the findings. The Darkan site gave mixed results with one Linseed variety stubble producing a higher barley yield than canola stubble and the other variety lower.
Overall 2021 was an exceptional season with good rainfalls received across the entire season. In good seasons it is difficult for soil borne pathogen trials to show differences in results as roots that may be impacted by disease are still able to access enough moisture to grow a healthy crop. It is in poorer seasons that the benefits of reducing soil disease can be shown in crop yields as better developed root systems are able to access more moisture.