sbl

As for the environmental consequences of excess nutrients, much of the problem could be reduced by better land management--buffer zones to absorb runoff, retention areas and reduced application rates. Many corn farmers over apply fertilizer for that 1 yr in 5 when the have sufficient rainfall to use the extra fertilizer.

As Turtile said P from intensive animal farms (hogs, chickens and cows) is as much of the problem as row crops. However, I still think that in coastal waters, overfishing is as much of the problem as nutrient input.