For farming on a forest floor, I would expect overly complex variance.. For farming in a field, why isn't the deviance you calculate between the needs of plant location 1 & 2 on a frequent basis not a reasonable estimate to update the predicted needs of one plant every time you pass over the other?

I can imagine that a lot of small devices becomes economically viable.. I find that unfortunate since I think it will be a lot of permanent ewaste lost in fields relative to very temporary water optimization benefits.