These are pretty basic and harmless chemicals which support all modern farming methods.
The only questionable/toxic elements arrise from the use of pesticides. Without the ability to deter bugs/insects from consuming these plants there would be little chance of the crop surviving long enough for harvest. The whole idea of seeding a massive area with just one variety of plant is something almost never seen in the natural world. Insect numbers would balloon until the resources had been devoured, then the numbers would decrease as the food source dries up.
End of the day, without modern farming techniques we'd all be starving. Organic farming tries to subsitute fertilizer/pesticides with crop rotation/crop diversity with some success, however most cannot be harvested or planted using modern equipment, limiting itself to pretentious, cashed up elitists.