"But why would you want to turn farming over to machines?"
Ahem! Farming has been conducted primarily by machines for going on a hundred years, at least in the United States. I want to substitute intelligent machines that proceed carefully and work continuously for big, dumb machines that are designed to get the job over with as quickly as possible, and at the same time move farmers out of their roles as machine operators and into the roles of technician and manager.
The threshold that still looms large but is shrinking with every passing week, primarily due to advancements in military robotics, is autonomous operation, making it possible for one person to manage many machines simultaneously, instead of being symbiotically fused to one for the entire time it is in operation.
At some point in the not too distant future, it will become practical to turn tractors loose under robotic control, but by the time that happens that same threshold will already have been crossed by less powerful, less dangerous machines. Moreover, once tractors arrive at autonomous operation there's not much to drive further development. Sure, you can push efficiency higher and accident rates lower, but it's still the same old thing.
With the sort of detail-oriented systems I've been attempting to imagine and describe, that threshold of autonomous operation is just the beginning, the spark that lights the rocket. Knowledge that would be of no use to autonomous tractors, because they'd still just be pulling implements around a field, could improve the performance of machines using a horticultural approach and improve the productivity of land they tend, and much of that knowledge they would be able to discern for themselves, through experience (statistics applied to crop measurements) and sharing information with each other.
For every increment in sensory capability, processing power, mechanical versatility, and software sophistication there would be a potential payoff, in machine performance, productivity, and/or the quality of the overall result.
That's what a growth market looks like.