GK is a mathematician, not expert in this material. There may be parts that are false.
GRDC: "Accurately measuring nitrogen in the soil profile at sowing is another essential component to nitrogen budgeting."
I think a good early paper is
Mason, M G. (1968) "Nitrogenous fertilisers for cereal production," Journal of the Department of Agriculture, Western
Australia, Series 4: Vol. 9: No. 5, Article 6.
Available at: https://library.dpird.wa.gov.au/journal_agriculture4/vol9/iss5/6
The varieties of wheat, the soil types and rainfall patterns all matter, but don't get a mention by me below.
Urea is CO(NH_2)_2
https://en.wikipedia.org/wiki/Urea
Urea is primarily produced in Australia at Incitec Pivot’s Gibson Island plant in Brisbane, which is currently the nation's only manufacturer.
However, the major $6 billion Perdaman Urea Project (to use gas from Woodside) is under construction on the Burrup Peninsula near Karratha, WA, set to produce 2.3 million tonnes annually.
NeuRizer, at SA gas fields, also possible.
WA farmers can buy urea (and other fertilizers) from CBH and/or CSBP(Wesfarmers) amongst others.
Can be bought at Kwinina and other places.
GK wonders if, depending on weather/rainfall, it might be reasonable to apply urea (and?) fertilizer in 2 applications.
Suppose the amount M for a single application is calculated, for example, from the quadratic in
A simple N calculator for achieving water-limited yield of wheat cropsZvi Hochman, Francois WaldnerProceedings of the 20th Agronomy Australia Conference, 2022 Toowoomba Qld
www.agronomyaustraliaproceedings.org
The suggestion is to apply say 4M/5 just before seeding and M/5 within 3 weeks after seeding, the exact day depending on rain.
For the 2nd application, a dry day for the application with the right amount of rain the next day would be good.
(and?) gemini said: "While granular urea is dominant, the use of liquid Nitrogen (UAN, often branded as Flexi-N or similar) is also common, particularly as a flexible in-season or in-furrow option."
Nitrogen can be applied in various forms. Urea is the most commonly used in WA wheatbelt.
Urea can't be applied concurrently with super phosphate, etc. (Doesn't go through machine that well in a mix.)
Can be applied before seeding.
Can "burn" wheat seed if applied at seeding.
Urea doesn't get taken up by the wheat directly.
It needs to be made to release nitrates and ammonia/ammonium, which are the chemicals the wheat takes up.
Rain is needed to wash the urea into the soil, and rain and microbes to get it bonded into organic matter etc
Microbes play a very important role in converting organic matter the urea, etc. to nitrate and ammonia/ammonium.
https://www.incitecpivotfertilisers.com.au/contentassets/685c44072b924c5d909ffeeaf83cd19e/31-urea-agritopic.pdf
Google:
Based on late 2025 and early 2026 market reports, nitrogen fertilizer prices in Western Australia, e.g. ex-Kwinana, have remained elevated due to strong international demand and tight local supply.
Here are the estimated bulk, ex-works/terminal prices for nitrogen fertilizers in the Kwinana area as of late 2025–early 2026:
Estimated Bulk Nitrogen Fertilizer Prices (Kwinana Area)
Granular Urea (46% N): ~$835–$1,004/tonne (ex-Kwinana): Prices saw increases in late 2025.
Note: As of September 2025, CSBP adjusted prices to roughly A$951/t ex-Kwinana.
Flexi-N (Liquid Nitrogen - UAN):
Production increased at the Kwinana Distribution Centre in 2025, with local supply available, but specific per-tonne prices vary based on volume and contract. (CSBP, Summit)
Ammonium Sulfate (Granular):
Available through regional agricultural suppliers, with prices often reflecting high raw material costs (ammonia/sulfur).
(CSBP and various NK mixes)
Key Market Factors & Information
Supplier Activity: CSBP(WesCEF/Wesfarmers) and CBH are major players in the Kwinana area for importing and distributing dry and liquid fertilizers.
Supply Outlook: While international urea prices eased in mid-2025, local Western Australian prices remained high due to tight supply and early, strong import programs.
Price Volatility:Prices are highly volatile and dependent on Indian import tenders and Chinese export quotas.
Disclaimer: Fertilizer prices growers contact major suppliers in the Kwinana industrial area (e.g., CSBP, CBH, Summit Fertilizers, Nutrien Ag Solutions) for daily, precise quotes
(Summit wholly owned by Japanese trading house Sumitomo.)