Factors affecting canola establishment in Australia

This report summarises three activities to identify current best management practices for canola establishment across Australia and knowledge gaps and industry priorities for further research. 1. A literature review was conducted on management and environmental factors affecting canola establishment. This built upon existing reviews but included grey literature such as on-farm trials not normally included in formal literature reviews. The main research opportunities identified were (i) improved understanding of how moisture and temperature interact to reduce establishment when sowing early; (ii) the impact of sowing depth on canola establishment and the ability to “moisture-seek” with deeper sowing; (iii) the impact of crop residue/stubble on establishment under early sowing; (iv) the effect of soil crusting. 2. An online industry survey was carried out between 9 Feb and 28 March 2023. In total there were 126 respondents across the key canola growing regions in Australia. The results showed that farmers generally aimed for 20-40 plants/m2 and were achieving estimated field establishment rates of 60-80%. The issues contributing to poor establishment were: (i) marginal soil moisture, (ii) seeding depth and furrow infill, (iii) surface crusting and (iv) stubble/residue issues. A range of establishment pests were also identified as currently reducing establishment. In terms of farmer and consultant research priorities the most mentioned keywords were ‘depth’, ‘hypocotyl’, ‘moisture’, ‘stubble’ and ‘vigour’. 3. Direct industry consultation was sub-contracted to ‘AgInnovate’. Initially we planned farmer/consultant workshops but found limited interest. Instead AgInnovate contacted grower groups directly and interviewed them. The key conclusions were that the nature of the seasonal break (timing, and amount of rainfall) is a main contributor to establishment success of canola and seed survival in marginal breaks was a research priority; Vic, NSW and SA groups said their establishment rates were < 50-60%; Queensland growers wanted the research to provide answers regarding fungicide applications and seeding depths. Clearly the consistent themes emerging from these activities regarding poor canola establishment and areas to focus further research were: • Optimum sowing date and sowing decisions. Information and tools are required to make decisions around early sowing with respect to soil moisture and temperature thresholds. • More information on optimum sowing depths under different conditions is required, particularly in the context of early seeding. • The impact of stubble on moisture retention, temperature and canola establishment should be re-examined. • The impact of factors leading to soil crusting and contributing factors needs more research.