Improving Canola Nitrogen Use Efficiency (NUE) - Phase 1

Nitrogen (N) is crucial for canola development as it is not able to fix atmospheric N like legume crops and has a high N requirement. Canola requires approximately 80 kg N/ha/tonne of yield which is double that of wheat and barley (Ag Vic, 2023). It is estimated that for all cereal crops they are only able to recover about 50% of the N applied to the soil (Silva et al. 2020). In canola about half the N taken up, goes to the seed, whereas in wheat this value is closer to 85%.

Crop NUE consists of two components: N uptake efficiency (NUpE) which is the plants’ ability to absorb N from the soil and N utilisation efficiency (NutE), is the plants’ ability to partition absorbed N to specific plant organs and equates to the amount of grain produced per unit of N uptake at maturity (Oliveira Silva et al. 2020; Williams et al. 2021). NutE is sometimes also referred to as Nitrogen Remobilisation Efficiency (NRE). This investment will seek to understand the N uptake of current and select diverse canola varieties, however, will have an additional focus on the NUtE. Given that the NUtE of Canola is 35% lower than that of wheat, and it has been found that variation in remobilisation of N under high N conditions is mainly caused by variation in NUtE (Stahl et al. 2019).

If we can increase NUtE in canola by 8% this may result in 2 scenarios for the grower. The first is that less N fertiliser would need to be applied due to improved utilisation of N that is already being taken up by the plant to achieve the same amount of yield, or if they continue to apply the same amount of N, greater yields may be achieved as the plant is better able to utilise the N that is being applied.

There are other factors however that need to be considered, such as there being a N deficit for the next crop, resulting in costly N fertiliser top-ups. Additionally, high fertiliser and N application is known to contribute to GHG emissions with nitrous oxide accounting for 5-7% of global greenhouse emissions, 90% of this being derived from agricultural practices (Nitrogen fertilisers, 2023). Countries such as New Zealand, Canada and the Netherlands have targets to reduce GHG emissions which includes reductions in fertiliser use (Wiesemeyer, 2022; Government of Netherlands, 2022; Government of Canada, 2023). Enhancing NUE in canola would have an impact on grower profitability whilst also enabling GRDC to meet its sustainability objectives in the new 2023-2028 RD&E strategy.

Please note the following:

- Collaboration between research organisations, breeding companies and industry experts is encouraged. All collaborations should designate a lead organisation as per the Tender Terms and Conditions.

- Co-investment from research partners is highly valued and GRDC is seeking a 50:50 co-investment ratio for this contract. Please see the budget template for definitions of cash and in-kind contribution.