Hmm.
Part of me hesitates to put this up here, but . . ..
Some of you may be old enough to remember India's vaunted "Green Revolution" beginning in the 1960s, as a consequence of which India went from being dependent on U.S. foreign aid food imports to more-or-less self-sufficient in food.
Until recently.
According the linked article by the Wall Street Journal, a big part of the GR was the subsidized production of fertilizers, especially urea, provided to farmers at greatly subsidized rates.
But now, India's soil has lost its balance of nutrients, causing per-acre yields of rice and other crops to decline, as farmers pile on more fertilizer.
Yes, I know, this is a really EXTREME example, but I guess my point is that if you have to use fertilizer, be careful, and don't neglect your organics . . . .
CLICK HERE FOR WSJ article.