24th September 2026
Farmers are once again having to keep a close eye on fertiliser prices, with the cost of some of the key products used to grow crops remaining well above the levels seen before the latest international disruptions.
For farmers, fertiliser is not an optional extra. Nitrogen, phosphorus and potassium are the three major nutrients needed by crops, although the amount required varies between crops and soils.
The current situation is particularly interesting because nitrogen and potash are facing different problems.
Nitrogen fertiliser is closely tied to the energy market, while potash is much more dependent on a relatively small number of producing countries.
Nitrogen is the immediate concern
Nitrogen fertiliser is particularly sensitive to the price of natural gas because gas is a major input into its manufacture.
AHDB estimates that natural gas accounts for around 60–80% of the production cost of nitrogen fertiliser. That means a sharp rise in gas prices can quickly feed through into the cost of fertiliser bought by farmers.
The latest GB figures show how much prices have moved.
For the week ending 11 September 2026, UK-produced ammonium nitrate was averaging £473 a tonne, while imported ammonium nitrate was £472. Granular urea was £471 a tonne.
Compared with February 2026, before the latest international disruption, UK-produced ammonium nitrate was £71 a tonne higher, an increase of 17.5%. Imported ammonium nitrate was £68 higher.
That matters because nitrogen is one of the major variable costs faced by arable farmers.
It also illustrates how quickly events elsewhere in the world can reach a Scottish farm.
AHDB reported earlier this year that the Middle East conflict initially pushed imported ammonium nitrate up by £130 a tonne and granular urea by almost £200 a tonne by mid-April. Around 35% of global urea exports pass through the Strait of Hormuz, making shipping disruption an important risk to the market.
Prices have subsequently settled considerably, but remain higher than before the disruption.
Potash is a different problem
Potash provides potassium, the third major plant nutrient alongside nitrogen and phosphorus.
It plays an important role in plant development, water regulation, crop quality and resistance to stresses such as drought and disease.
Unlike nitrogen, potash production is not primarily dependent on natural gas. The major issue is the concentration of global production in a relatively small number of countries.
Canada, Russia and Belarus together account for around 70% of global potash production.
That concentration has been a concern since Russia's invasion of Ukraine and the resulting disruption to international trade. Belarus is also a major producer, but Western sanctions and changes to trading routes have affected its access to some markets.
For Britain, however, the present situation needs to be put into perspective.
There is not currently a general shortage of potash in Britain.
Indeed, the latest AHDB figure for Muriate of Potash, or MOP, was £364 a tonne, actually £2 below its February 2026 level.
That compares with the much larger increase in nitrogen fertiliser.
So the immediate British problem is more accurately described as exposure to international supply and prices, rather than a shortage of potash.
Britain remains dependent on imports
This is nevertheless an important vulnerability.
Britain produces very little of the potash it needs and therefore depends on international suppliers.
That means British farmers are exposed to events over which they have little control.
A mine disruption in Canada, problems with Russian exports, sanctions affecting Belarus, shipping difficulties or a sudden increase in demand could all influence the international price.
The same applies to nitrogen, although the supply chain is different.
Britain has some domestic nitrogen production, but farmers also depend on imports. Natural gas prices, international competition, shipping and energy policy can all affect the final price.
This is one reason fertiliser has become part of the wider discussion about food security.
The farmer faces the squeeze from both directions
The difficulty for farmers is that they cannot necessarily respond to higher fertiliser prices simply by putting less on the fields.
There is a balance to be struck.
Using less nitrogen can reduce costs, but if applications fall below what the crop requires, yields can suffer.
Potassium is slightly different because soil reserves can provide some of the crop's needs. A farmer may be able to reduce applications for a period if soil tests show adequate potassium levels.
But repeatedly mining soil reserves without replacing nutrients is not a sustainable long-term strategy.
The calculation therefore becomes one of fertiliser cost against expected crop prices and yield.
That is particularly important when grain prices are weak.
A £50 or £100 increase in the cost of a tonne of fertiliser is much harder to absorb when the farmer is already receiving relatively low prices for the crop.
AHDB noted earlier this year that fertiliser prices had risen by about 14% during 2025 compared with 2024, while grain prices were also putting pressure on farm margins.
It eventually reaches the consumer
Fertiliser is only one part of the cost of producing food.
Farmers also face higher costs for fuel, machinery, labour, electricity, transport, seed, chemicals and finance.
But fertiliser is particularly important because it directly affects crop production.
If fertiliser costs remain high, farmers have several choices. They can accept lower margins, reduce applications where agronomically possible, change crops, improve efficiency or hope that crop prices rise sufficiently to compensate.
Over time, persistent increases in production costs can feed through the food supply chain.
That does not mean that a £50 increase in a tonne of fertiliser will suddenly appear as a corresponding increase in the price of bread or meat. The relationship is much more complicated.
But it is another example of how an international event can eventually affect the cost of producing food in Britain.
A warning about depending on a small number of suppliers
Perhaps the biggest lesson from the current situation is not that the world is running out of fertiliser.
It is that some of the world's most important agricultural inputs are produced in relatively few places.
Potash is a particularly good example.
Nitrogen has a different vulnerability because its production depends heavily on natural gas.
That means the two nutrients can be affected by completely different events but ultimately create the same problem for farmers: higher and less predictable production costs.
The UK Government has increasingly recognised fertiliser as a food-security issue. A recent report on Britain's preparedness for geopolitical shocks argues that fertiliser supply deserves greater attention because disruption can affect agricultural production and therefore food security.
For farmers in Caithness and the wider Highlands, international fertiliser markets may seem a long way away.
They are not.
The price of natural gas in another part of the world, a disruption to shipping, sanctions affecting a major potash producer or a change in international demand can eventually appear on the invoice from the local agricultural merchant.
And that is why fertiliser prices are worth watching even when there is no immediate shortage.
For now, nitrogen is the more obvious price problem in Britain. Potash is the longer-term supply-chain vulnerability.
For farmers, the challenge is that they need both.