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Fertiliser timing and pricing basics

When to apply nitrogen and what drives the price you pay, based on DPIRD and GRDC research.

Fertiliser is one of the biggest costs in a cropping program. Getting the timing right and understanding what drives the price can both save money. This guide covers the basics; your agronomist knows your paddocks.

Timing nitrogen

  • Nitrogen is best applied when the crop can use it. DPIRD's long-standing guidance for WA cereals is to apply close to seeding in shorter-season, drier areas, and to consider delaying by a few weeks in high-rainfall areas or on light, sandy soils where leaching is a risk (DPIRD).
  • Very late nitrogen is less likely to lift yield but can lift grain protein. DPIRD and GRDC research on malt barley found delaying more of the nitrogen until stem elongation raised protein by 0.5 to 1 percentage points with the same amount of nitrogen, though some late strategies cut yield (DPIRD).
  • Splitting nitrogen lets you match top-ups to how the season is shaping up, rather than committing everything at seeding.
  • Soil tests and paddock history help decide how much you need. Results vary by season, soil and crop, so no timing guarantees a yield.

What drives the price

  • World prices. Most Australian fertiliser is imported, so local prices follow world urea and phosphate prices, which are quoted in US dollars (World Bank).
  • The Aussie dollar. A weaker dollar makes imports dearer.
  • Freight and timing. Shipping, port and road freight costs add up, and demand peaks before seeding and during in-season top-ups.
  • The local margin. AgIndex's fertiliser chart shows the gap between Australian farmgate pricing and the world price in Aussie dollars.

Buying tips

  • Compare quotes on the same basis: price per tonne, ex GST, same depot, same delivery or collection terms.
  • For nitrogen, compare on cost per kilogram of nitrogen, not per tonne of product. Urea is 46% nitrogen.
  • Watch the world price trend and the dollar for a few months before booking. Booking early can lock in a price, but it can also lock in a high one.

Related: fertiliser prices · find an agronomist. General information only, not agronomic advice.

Sources

General information only, not financial, legal or agronomic advice. Check details with the manufacturer, your dealer and product labels. Last reviewed 16 October 2026. Spot an error? Tell us.