RiskWi$e focus sites in 2024:
- Cootra
- Minnipa
- Port Kenny
- Lock
- Cockaleechie
- Cleve
June 2024Â
Optimising Crop Yields in 2024: 2024 Season So Far…
Due to the delayed start to the season, crops across the Eyre Peninsula have mostly started emerging in early to mid-June. Generally, crops that establish in June don't have enough time to build up biomass before they enter the reproductive stage. This increases the likelihood of flowering during hotter conditions, which usually results in lower yield potential compared to crops that establish in early May.
However, tools like Yield Prophet® are forecasting that a wide range of potential yields are still possible across all Eyre Peninsula environments given the range of climatic conditions that may still eventuate. Examining the six focus paddocks being followed by the GRDC RiskWi$e project, in some cases, sees shortfalls in the amount of nitrogen available in the soil, if potential yields are to be realised.
Table 1. Eyre Peninsula focus paddock summary information: paddock history, yield potential and nitrogen shortfall, June 2024.
This poses questions like how much N should be applied, where and when? The following article aims to provide a framework that might be a useful guide to work through the decision.
What is Yield Prophet?
Yield Prophet® is a crop modelling tool that simulates crop yields based on local climate data and soil conditions. It predicts potential yield outcomes across various seasonal conditions, ranging from the wettest to the driest years. These outcomes are often expressed in deciles: Decile 1 represents the lowest 10% of years, and Decile 10 represents the highest 10%.
The platform generates graphs that illustrate potential grain yield outcomes. A solid blue line shows yield based on rainfall alone, while a dotted blue line accounts for the negative effects of frost and heat. The green line indicates current yield potential, considering initial nitrogen levels and modelled nitrogen availability through mineralization. These graphs help farmers understand crop yield potential and make informed decisions about inputs and economics.
Decision-Making with Yield Prophet
Making economic decisions about nitrogen application is most effective when considering multiple seasonal outcomes. Farmers aim to either profit from the yield response or minimize losses when there's no response. However, oversimplifying these decisions can lead to unexpected results.
The RiskWi$e Project
Funded by GRDC, the RiskWi$e project aims to help farmers with decision-making in complex or complicated situations. Using focus paddocks across different environments on Eyre Peninsula, we examine yield potential, yield gaps, and decision-making processes to reduce risk and uncertainty.
Example Scenario: Eyre Peninsula Wheat Crop
Consider a wheat crop with a 2.5-tonne yield potential in an average year. If a grower has enough nitrogen for a 2-tonne crop, what should they consider when deciding on additional nitrogen application? Here's a breakdown:
- Urea cost: $730/tonne (including freight)
- Spreading 40 kg/ha of Urea: $37/ha
- Total cost for 1,500ha: $55,500
- Profit from a 0.5 t/ha yield increase: $285,000 (1,500ha at $380/tonne)
- Yield increase needed to cover input costs: 0.1 t/ha
Based on this information, the potential outcomes could be:
- In 3 out of 10 years, no yield response (loss of $55,500)
- In 4 out of 10 years, full yield response (profit of $285,000)
- In 3 out of 10 years, partial yield response (breakeven)
On average, spreading Urea could yield a profit of $103,000 per year. Conversely, not spreading could cost the grower $103,000 annually.
Key Questions for Decision-Making
To make a well-informed decision, consider the following:
- Can my business handle a $55,500 outlay if it's not recouped? How many years can I sustain this without financial risk?
- Will unused nitrogen remain in the system for future use?
- Is my paddock responsive to nitrogen? Do I understand soil nitrogen levels well enough?
- Can I expect a response across all soil types? If not, how can I address this?
- Do I need more information, and where can I find it?
Conclusion
Having a structured decision-making process can be really valuable when making decisions that are complex or have high levels of uncertainty. While no single method is perfect, a thoughtful approach helps manage the complexities of farming decisions. Below are the yield potentials and nitrogen-limited yields for six focus paddocks, providing valuable insights. More detailed Yield Prophet reports are available (see downloads further below).
Note that sowing dates are relative to establishment, many sites were sown earlier but the dry start to the season has resulted in delayed establishment dates.
Cleve focus site 14 June 2024
Cockaleechie focus site 14 June 2024
Cootra focus site 20 June 2024
Lock focus site 14 June 2024
Minnipa focus site 14 June 2024
Port Kenny focus site 14 June 2024
April 2024
How is the 2024 season shaping up and how can nitrogen strategy be approached?
With seeding just around the corner (or already started for some), many growers are considering questions like: how will the season turn out? How much of the rain we had last December is still available for this year’s crop? Should I be targeting above average yields? How much money should I spend on this year’s crop?
Crop yields hinge on numerous factors, but if you were to ask most people, they'd likely agree on one primary factor: rainfall. Rain drives good yields, while its absence leads to the opposite outcome. Predicting when to make the best of a good year or cut costs on a poor year can make farming a bit of a 'dark art' as growers navigate a range of decisions. Often, these decisions are based on years of experience, where growers rely on intuition or gut feeling. This intuitive approach often provides a solid base for decision-making and outcomes, but can see some opportunities lost or overspending on poor years.
An alternative approach involves 'calculated' decision-making. It typically involves sitting down, perhaps with a calculator, scribbling numbers on the back of an envelope, or better yet, using a computer and spreadsheet. While this method still incorporates intuition, it presents information in a way that allows growers and/or consultants to clearly weigh the benefits against the risks.
The framework, developed by Barry Mudge and Peter Hayman, where a range of outcomes to decisions are considered, provides a means of examining all outcomes simultaneously to make well-informed decisions and forms part of GRDC’s RiskWi$e initiative. It's about calculating and potentially minimising risk and maximising rewards within a farming operation.
As part of the RiskWi$e project, six paddocks were chosen to run Yield Prophet® on, serving as examples to discuss with growers. This approach benefits from using real numbers from the local area, making them more relatable. The following provides an example of how nitrogen decisions and their long-term outcomes could be worked through to consider a range of outcomes.
Overall, the aim of the RiskWi$e project is to assist growers in managing risk. It's not to suggest that growers aren't already adept at doing so, but rather to work through a range of tools where the spectrum of possible outcomes are considered.
We aim to regularly update the information provided for the focus paddocks, to help track how nitrogen applications respond to seasonal conditions and yield forecasts.
If you require any further information or would like to discuss the way you are approaching nitrogen decisions for the upcoming season, please contact Jacob Giles, EPAG Research, Port Lincoln, 0431 110 018 or jacob@epagresearch.com.au.
All the best for a fantastic opening to the season and a smooth seeding.
Cleve focus site 15 April 2024
Cockaleechie focus site 15 April 2024
Cootra focus site 15 April 2024
Lock focus site 15 April 2024
Minnipa focus site 15 April 2024
Port Kenny focus site 15 April 2024
