Curing overuse is a fine thing and high fertilizer prices drive that. Instead of broadcast application GPS monitoring of both application and yield can be done. Doing it right involves a guy on an ATV with a GPS and some kit doing a field survey first.

 The livestock stuff is a problem but keep in mind human waste is simply dumped in a lot of those municipalities. Spencer, Iowa, population about 9,000 has a direct discharge sewer system. That all reaches the Mississippi along with every other little town in the Midwest that does that ...