The Fertilizer Chokepoint: How the Strait of Hormuz Blockade Threatens Australian Grain

While Australian headlines focus on petrol prices, which makes sense from a consumer perspective, the conversation in boardrooms from Singapore to Sao Paulo has shifted to something less visible and more consequential: fertilizer.

About one third of global seaborne fertilizer trade normally passes through the Strait of Hormuz. When American and Israeli strikes on Iran in late February triggered retaliatory closures across the Gulf, nearly a million metric tonnes of fertilizer cargo became stranded within days. That cargo was supposed to be in the ground across the Northern Hemisphere by April.

Where Australia actually gets its fertilizer

The dependency is deeper than most Australians realise. In 2024, Australia consumed 8.7 million tonnes of fertilizer valued at A$5.5 billion. Imports accounted for 7.9 million tonnes, an increase of 38% on the previous year. Domestic production has declined to just 1.3 million tonnes, covering only 15% of total consumption.

Urea alone, the most widely used solid nitrogen fertilizer, represents 44% of Australian consumption, with more than half of Australia's urea imports coming from the UAE, Qatar, and Saudi Arabia. These are precisely the countries now cut off by the Hormuz blockade.

These numbers matter because timing matters just as much, and Australian farmers are entering winter planting season when reliable fertilizer supply is not optional. Wesfarmers, which operates the nation's largest fertilizer distribution network through its chemicals division, warned in early March that shipments of ammonium phosphate and urea would likely be delayed.

Initially farmers, they suffer, but of course they transmit that to the supply chain.

— Vitor Pistoia, Senior Grains and Oilseeds Analyst, Rabobank

The price signal from New Orleans

Fertilizer markets responded within hours of the Gulf closure. Urea at the New Orleans import hub jumped from USD 516 to over USD 680 per metric tonne in the first week. That 32% increase happened while vessels were still calculating whether alternative routes made commercial sense.

Global urea prices have risen approximately 25% overall, with sharper gains in markets closer to the disruption. The American Farm Bureau Federation estimates that countries exposed to Persian Gulf instability account for nearly 49% of global urea exports and about 30% of ammonia exports. When that much supply disappears from the market simultaneously, price discovery becomes volatile.

The cascade extends beyond nitrogen into other agricultural inputs that depend on Gulf supply chains. Sulphur, which accounts for 44% of global supply from the Gulf region, feeds phosphate fertilizer production worldwide, so when sulphur shipments stop, phosphate plants in Morocco and Tunisia slow down, creating secondary constraints for Australia's monoammonium phosphate imports.

What the data shows versus what farmers feel

The American Farm Bureau captures the gap between aggregate statistics and lived experience clearly. In the United States, roughly 97% of potassium fertilizer is imported, along with 18% of nitrogen and 13% of phosphate. Even those modest import dependencies create vulnerability during supply shocks.

Australia's position is considerably more exposed, with approximately 99% of the nation's ammonium sulphate imported from China, which offers partial substitution capability during urea shortages but with agronomic differences that limit direct replacement. A wheat farmer cannot simply swap nitrogen sources mid-season without affecting yield outcomes.

Across the Northern Hemisphere, the timing is particularly painful, with corn planting in the American South beginning in late January and continuing through March while winter wheat across the Southern Plains requires nitrogen applications during spring growth. In the Corn Belt, farmers are finalising purchases for April planting, and every week of delay compounds the pressure on an already strained supply chain.

The view from regional trading desks

Indian officials are quietly concerned because India buys more than 40% of its urea and phosphatic fertilizers from the Middle East, and a recent agreement to purchase 1.3 million tonnes of urea may not arrive on schedule. Bangladesh has shut four of its five fertilizer factories due to feedstock constraints.

Brazil, which supplies a meaningful share of global soybean production, imports almost 100% of its urea. Nearly half of that typically transits the Strait of Hormuz. When Brazilian farmers compete for alternative supply from North Africa or Southeast Asia, Australian importers face the same competition.

The UN Trade and Development agency published a rapid analysis noting that developing economies may be particularly exposed. High debt burdens and rising borrowing costs limit their ability to absorb new price shocks. For food-importing nations in Sub-Saharan Africa, the fertilizer disruption compounds existing pressures from elevated grain prices.

What happens to Australian food prices

The transmission from fertilizer costs to supermarket shelves is slower and less direct than petrol price movements. Retail food prices in high-income countries are determined primarily by processing, packaging, and marketing costs rather than farm-gate input prices.

Former ACCC chair Allan Fels suggested that costs on perishable goods such as dairy, fruit, and vegetables could rise by 40-50% if fuel and fertilizer constraints persist, though economists offer important qualifications: Australian farmers absorbed the 2021-2022 pandemic fertilizer price surge without immediate consumer impact because they had margin to absorb temporarily elevated input costs.

The current situation differs in one significant respect. Farmers have already been absorbing elevated costs for three years. The margin buffer that existed in 2022 has thinned. If the Hormuz blockade persists through the second quarter, Northern Hemisphere planting disruptions will feed into autumn harvest outcomes. That timeline matters more for global food security than Australian domestic prices.

No quick fix available

Even if the Strait of Hormuz opens tomorrow, restoring fertilizer supply chains will take weeks. Plants that shut down due to feedstock constraints cannot restart instantly. Ships rerouted around the Cape of Good Hope face transit times that push deliveries past planting windows. The Carnegie Endowment noted that these are weeks Northern Hemisphere farmers do not have.

For Australian farmers, the winter planting window provides slightly more time than their American or European counterparts, but the supply chain is global and interconnected. When American buyers scramble for Southeast Asian urea, Australian importers compete for the same limited cargo, and when Brazilian demand increases, shipping rates and insurance premiums rise for everyone.

The RBA has indicated it is too early to assess inflation implications, and that caution is appropriate given that the interaction between energy prices, fertilizer costs, and yield outcomes creates uncertainty that resists simple forecasting. What does seem clear is that Australian agriculture faces a supply vulnerability that domestic headlines have not adequately communicated.

The Strait of Hormuz carries around one quarter of global seaborne oil trade, a figure that gets repeated frequently in energy coverage, but it also carries one third of global seaborne fertilizer trade. That second figure appears far less often in headlines, though its consequences for food production may prove equally significant.