[algoatecorn]

We're not moving away from nitrogen fertilizers. Ever. Why?

Look at the following three graphs: global population, staple crop yield, and nitrogen fertilizer application.

Now overlay them. That's why.

Also, there are myriad chemical inputs that cannot be removed simply due to free labor. Sure, a robot can pluck weeds, but what about fungal and bacterial diseases?

[dukeyukey]

There are absolutely automated systems out there to handle recognition and application of whatever fertiliser/fungicide is needed. Not cheap of course, but prices will come down.