A Saskatoon commodity analyst says a large number of farmers planting corn for the ethanol market could put a strain on the fertilizer supply for Prairie farmers this spring.

Larry Weber says farmers are planting record amounts of corn, which has created an unprecedented demand for fertilizer.

That could result in a shortage in Western Canada, he said.

"It's going to be very difficult, if you haven't already purchased fertilizer yet, going forward, to buy fertilizer," Weber said.

Even if farmers bought fertilizer months ago, they might be out of luck if it's not in their possession right now, Weber said.

Some farmers bought in the fall, but they may not be able to pick it up this spring if dealers can't get the supplies.

"If there is no more coming, it's going to be on a first come, first serve basis. And regardless whether you paid for it in November, October or December of last year, the most important thing that you can have is that fertilizer sitting on your farm," he said.

Supplies could get even tighter if there are any labour disputes with either of the railways, said Weber.

Canadian Pacific Railway could be facing a strike later this month, and there's still a chance that workers won't ratify the agreement with CN Rail, he said.

If the trains aren't running, farmers won't get their fertilizer, Weber said.