With production across Gulf countries halted and gas prices climbing, the war in Iran and the wider Middle East is disrupting fertilizer supplies and raising concerns over global food security.
A third of fertilizer shipped by sea comes from the region and cannot make it to the global market as Iran has effectively closed the Strait of Hormuz.
That has sent global fertilizer prices soaring, with the U.N. expressing concern in particular about the impact on developing countries.
Natural gas is a key feedstock to make artificial fertilizers, and with its ample gas supplies, the Gulf region has become a key manufacturer.
The region produces nearly half of the sulphur sold worldwide and a third of urea, "the most widely traded fertilizer of all," said Sarah Marlow, global editor for fertilizers at Argus Media.
It also produces a quarter of globally traded ammonia, another feedstock for fertilizer production, she said.
Major food-producing nations like the U.S. and Australia source much of their urea and phosphate from the Gulf nations.
Brazil, the world's leading soybean producer, imports most of its urea from Qatar and Iran, which also exports to Türkiye and Mexico.
India relies upon Saudi phosphate.
Asia, in particularly dependent on the Gulf: it imports 64% of its ammonia and more than 50% of its sulphur and phosphates from the region, according to 2024 figures from Kpler.
But since the start of the conflict, which has seen Iran launch retaliatory strikes against its Gulf neighbors following U.S. and Israeli strikes, production has had to be shut down at fertilizer production facilities, particularly in Qatar.
And the Strait of Hormuz remains largely unnavigable.
A Chinese vessel loaded with sulphur was able to leave on March 7, but around 20 other ships were still waiting as of the middle of the week, according to Kpler, which tracks commodity flows.
While Europe appears at first blush to be less exposed, sourcing just 11% of its urea from the region, it will likely be impacted indirectly.
Morocco is a big supplier of phosphorus-based fertilizers to Europe, but is dependent on the Gulf for sulphur used in their manufacturing.
The EU also imports 26% of its urea from Egypt, but the country is confronted by a halt of natural gas supplies from Israel by pipeline, pointed out Argus Media consultant Arthur Portier.
"Egyptian urea has gone from $500 per ton at the start of the war to more than $650. There is a direct impact on the price of fertilizer," for European farmers, he said.
Other countries that source their gas from the Middle East to produce fertilizers, such as India, have had to ration supplies to their factories.
Bangladesh has temporarily shut down five out of six of them.
The U.N. expressed concern this week about access to fertilizers in some of the poorest countries.
Artificial fertilizers provide nitrogen, phosphorus and potassium necessary for crop growth.
For nitrogen-based fertilizers such as urea, ammonium nitrate and potassium, "global demand never ceases to increase, driven by Asia," said Sylvain Pellerin at INREA, a French agricultural research institute.
INREA models that without these three key fertilizer inputs, global crop production would fall by a third.
But nitrogen fertilizers require natural gas for their chemical synthesis, and a lot of energy.
As for sulfur, it is a co-product of the oil and gas industry.
"Where there is gas, you will find urea and ammonia," said the Argus's Marlow.
Production of phosphorus-based fertilizers starts with phosphate rock, of which Saudi Arabia supplies 20% of the world's total, but currently it is unable to ship it.
In addition to the uncertainty about how long the war will last, the other question is the amount of damage that fertilizer production facilities will suffer from the fighting.
Repairs and reconstruction of facilities could considerably delay a return to normality once the fighting ends.
While the immediate needs of farmers are more or less covered, there are questions about the sowing season in the southern hemisphere that begins in June.
Portier said the war could be the spark for Europe to develop a fertilizer supply strategy.
Following the surge in fertilizer prices following the Russian invasion of Ukraine, European farmers reduced their consumption and diversified their suppliers.
The European Commission is preparing a fertilizer action plan for this year.
