Author: Peter Hayman (SARDI Climate Applications), Barry Mudge (Mudge Consulting) | Date: 06 Feb 2024

Take home messages

• When choosing a single target yield for N budgeting, a grower has one chance in 10 of selecting the right rainfall decile and only considers the year of application. . Concern about applying too much N contributes to conservative rates which have been identified as an important cause of the gap in actual and potential yield and profit.
• For growers and advisers who do want to consider a seasonally responsive approach to N management, we have developed the Fast Graphs for Slow Thinking spreadsheet (Figure 2), which uses the 40kg N/t wheat rule to consider the upside and downside by budgeting across all 10 deciles. We also encourage users to vary the rate of N carryover and see how this changes the risk and reward outcome.

Author: James Hunt (The University of Melbourne) | Date: 06 Feb 2024

Take home messages

• Nitrogen (N) fertiliser rate decisions based on soil test data and a formalised decision process are more profitable than fixed rates or decisions based on ‘gut feel’.
• This article goes back to basics on N budgeting and is designed to help young agronomists make better N fertiliser recommendations.
• The article simplifies a lot of complex topics and should just be a starting point for learning about N management in southern Australian farming systems.

Author: Yolanda Plowman, Kate Finger (Birchip Croppin Group), Jame Hunt, Arjun Pandey (University of Melbourne), Mark Farrell (CSIRO) | Date: 17 Jul 2024

Take home messages

• Some growers struggle with making informed nitrogen decisions but decision support systems or approaches like Yield Prophet® and N banks can help.
• Both strategies produce ideal outcomes, however Yield Prophet may be an ideal tool for ‘active’ managers, whereas N banks may be ideal for ‘passive’ managers.
• In a multi-year N management trial (2018-2023), the YP50% and NB125 strategies provided high gross margins, whilst mitigating environmental N loss through lower (but positive) partial N balances.

Author: Lindsay Bell (CSIRO), Ismail Garba (CSIRO), Heidi Horan (CSIRO), James Hunt (University of Melbourne) | Date: 30 Jul 2024

Take home messages

• Developing a robust nitrogen (N) fertiliser strategy is critical to maximising seasonal yield potential while avoiding long-term carbon decline and mitigating risks of N losses
• Tactical N budgeting in the face of uncertain seasonal outcomes is tricky and has high data demands to make helpful predictions of seasonal yield potential
• Longer-term strategic approaches can be simpler and have advantages of incurring costs following higher profit years, but have higher risks of N losses
• Take a multi-year perspective on nitrogen use efficiency and return on investment rather than just the year of application
• Strategic approaches like N banking can perform well in northern farming systems allowing yield potential to be maximised while avoiding environmental losses
• Setting the appropriate N target to balance the upside and downside risks is likely to be influenced by your risk attitude.