Farm level considerations of sowing date for canola and wheat

Sowing date is critical in determining the yield potential and production risk (frost and heat shock) of an individual paddock. Multiple paddocks are sown in sequence each year with sowing date decisions made at the paddock level, but also within the context of a whole farm. Sequential sowing dates were demonstrated in this trial to raise awareness about the different sowing programs that might be employed on a farm. The trial was established (2014) at Cunderdin at the site which hosted the WANTFA Spring Field Day. Wheat (Mace @ 60kg/ha) and canola (IH30RR @ 3kg/ha) crops were sown at approximately 3 day intervals beginning on 29 April and finishing on 1 July (total 24 sowing dates). The trial, visited in spring by farmers and industry professionals, was a backdrop to discuss the risks and benefits of early sowing on yield and flowering date of a cropping program. The maximum canola yield of 1.21 t/ha decreased by 0.17 t/ha for each 10 day sowing delay. However, wheat yield was constant (2.9 t/ha) between 29 April and 1 June, decreasing thereafter by 0.56 t/ha for each 10 day sowing delay. These results demonstrate the importance of early sowing particularly for Canola. The flowering date for each time of sowing was also monitored, with the data used to discuss the spread of flowering across a cropping program, and the implications for frost and heat damage.