This spring, the most valuable commodity in agriculture is not sunshine or even rain, it is fertiliser.
By some estimates, up to half of global production of crops and livestock depends on the magical combination of minerals and chemicals that make up synthetic fertiliser.
But the Iran war is pushing up prices and squeezing availability of this fundamental element in the food chain at the start of the European and Asian growing season.
British fertiliser importers, farmers and growers have told Sky News that rising costs are squeezing food producers, and, in time, will trigger a food inflation spike for consumers.
Prices have rocketed because synthetic fertiliser is an energy product, dependent on the same natural gas we use to heat our homes and underpin our electricity grid.
The nitrogen that feeds plants around the world is produced from combining the hydrogen from methane (natural gas) with nitrogen in the air (via the Haber-Bosch process, familiar to chemistry students with long memories) to create ammonia.
Processed ammonia, in the form of urea or ammonia nitrate, is the raw material of industrial fertiliser, and up to 30% of global supply normally passes through the Gulf. As with oil and gas, the effective closure of the Strait of Hormuz has pushed up prices.
Urea has soared from close to $300 a tonne at the turn of the year to almost $700 by the end of March.
That leaves farmers facing a choice: pay double to produce a normal crop, a cost you may not be able to pass on to consumers immediately, or go without, and see yields shrink.
Either way, food prices will inevitably be forced up.
UK farmers, growers and ultimately consumers are exposed to these rising prices. Domestic fertiliser production has declined as industrial energy prices have risen and today we produce less than half of the synthetic fertilisers farmers…
