Then you have 1,000 separate ammonia generation systems that need upkeep, repairs, etc. It is doing chemical reactions under pressure to produce presumably ammonium nitrate which is explosive. The engineers you would need probably aren’t cheap, and storing large quantities of ammonium nitrate all year is sort of sketchy. Timothy McVeigh took out an entire federal building with about 4800 pounds of the stuff mixed with car fuel.
It’s usually a lot cheaper and safer to condense all that demand into a purpose-built facility where they can hire an engineer to look after all the generation, have centralized container storage, backup parts, etc.
None of that prevents putting the panels or windmills on farmer land, though. You could imagine some sort of “get a discount on ammonia if we can put a solar panel in your field” scheme. Or, even more simply, put up your own panels, sell the power back to the grid, use that money to buy fertilizer from the factory buying your power off the grid.
I don’t know the exact process but I don’t think ammonium nitrate actually gets involved. The system I was looking at (Green Lightning) actually doesn’t make ammonia but rather liquid nitrogen fertilizer
Plasma to take N2 + O2 -> NO2 and NO gas
The NO and NO2 are dissolved in water to become HNO2 and HNO3, which then become NO2- and NO3- ions in the water.
It’s a low pH solution which stabilizes it and then you dilute right before application so that you don’t burn the crops.