[UncleOxidant]

> While we fertilize the soil

For the most part farmers only add 3 macro nutrients when they fertilize: N,P,K. As you suggest there are many micro nutrients that are likely being depleted because they're not being replaced.

[bluGill]

Farmers are starting to put in Sulfur. It isn't common, and not a lot is needed, but some farmers need to. As acid rain goes goes down more and more will. (I'm always amused to see there is a downside of eliminating acid rain - still worth doing)