Not applying nitrogen fertiliser would reduce crop yields for some crops by as much as 50% in the first season, Holsether said.
"The fertiliser market is very global so these parts are moving across the planet, but the main destinations would be Asia, South East Asia, Africa, Latin America where you would see the most immediate impact from this."
Parts of the world where there is already under-fertilisation, such as several countries in sub Saharan Africa, could see an even larger impact on crop yields, he added, saying "significant drops" there were possible.
Planting seasons vary across the world. In the UK it is peak planting season, while in Asia farmers are getting started.
The consequences of fertiliser shortages in Asia will not appear in food prices until the end of the year, when harvests that should have been planted this spring come in smaller than they should, or not at all, according to analysts.
Professor Paul Teng, a senior fellow in food security in Singapore, said some countries might have enough fertiliser for the immediate planting season "but if the crisis drags on any longer, we will be seeing impact on crops such as rice in the coming months".
Farmers around the world are facing a daunting series of challenges, Holsether said, as the prices they can command for the food they produce have not yet adjusted to cover the higher bills they are facing.
"They're faced with higher energy costs, diesel for a tractor is increasing, other inputs for the farmers are increasing, fertiliser cost is increasing, but yet the crop prices haven't increased to the same extent yet," he said.