Optimizing high rainfall zone cropping for profit in the Western and Southern Regions

This proposal is focussed on reducing the gap between current and potential yield in the high rainfall zone. Activity will be targeted at wheat and canola. The high rainfall zone of southern Australia (HRZ) has an annual rainfall of 450-800mm in Western Australia and 500-900 mm in south-eastern Australia, and a growing-season of 7–10 months.

The HRZ has high crop yield potential however, current yield gaps are averaging at least 1 t/ha for wheat and 0.5 t/ha for canola in decile 2-5 years with an estimated 1-3 t/ha for wheat and 0.5-1.5 t/ha for canola in decile 8 years (Zhang et. al. 2006.)

A key driver of the yield gap identified in a review by Robertson et al. (2016) is timeliness of application of inputs and operational logistics (e.g. sowing, weed and disease control, crop flowering and nitrogen application). The top 25% of growers have learnt and adopted timely practices in the HRZ (PlanFarm Bankwest 2016-17) and there is strong evidence that by assisting those not in the top 25% to adopt these practices will close the yield gap (Robertson et. al. 2016). Understanding the reasons for these differences in grower behaviour will take into account the socio-managerial drivers, whole-farm logistics and their appetite for risk and impact on profitability.

The approach includes three small plot trials to assess a range of crop types and management combinations and modelling to assess how whole-farm logistics and appetite for risk influences productivity and profitability. These sites will be matched with participatory D&E sites to compare local district practice with a common set of system modifications, as informed by the small plot trials. A participatory research approach is proposed, including growers, researchers and advisers to increase the rate of adoption of the research findings and to inform the R&D activity.