Are they? Fertilizer prices are up 3x-5x, depending on where you look, due to Russian export restrictions, so for many farmers it's cheaper to wait it out and give the soil a rest.
Planting reports have only started trickling in, so we don't have a good global view of what has been planted in spring 2022.
If you play your cards right, and Mother Nature plays nice, this could be the most profitable year of farming seen in a long time. Costs are up, yes, but the income potential is up even more. Why would anyone choose this year, of all years, to "give the soil a rest"?
I find it hard to believe that land is going to lay fallow this year specifically because of what's going on. Certainly people are adjusting what they plan to grow to optimize for the situation. That is definitely happening.
https://www.theguardian.com/environment/2021/nov/25/fertiliz...
I'm in agreement with the idea that this isn't primarily caused by Russia's invasion of Ukraine. Read the author's other thread on fertilizer for more context on that.
She says it's primarily a shipping problem, not a production of fertilizer problem. Which tracks with the idea that this is simply another example of the global supply chain snarling things up.