The reason chemical pest control and broadly spraying fertilizer on the top of fields are a thing is that they have low labor costs. You'd get more efficacy if

The reason chemical pest control and broadly spraying fertilizer on the top of fields are a thing is that they have low labor costs. You'd get more efficacy if you walked the field and removed pests by hand or sprayed fertilizer only where you need it. It's the simple reason why a well-tended garden produces better produce than a corporate farm. There is simply more effort per plant in a garden. Tractors are currently too dumb to treat plants individually. They require plants to emerge, grow, harvest at the same time, and in the same way. Current modalities for pests/nutrition treat plants at the field level, not at the individual level. This creates lots of waste and externalities. If there were a robustly built robot smart enough to deal with plant issues in and individual way then there is a huge slice of efficiency that could be gained. A field with the productivity of a garden. People have been trying to create this for a decade now and the limiting factor is the software. Maybe with the latest round of AI advances that will change.