i dont think modern mechanized farming is compatible with having any kind of biosphere. so unless we stop farming on earth and do it on some magical FREE REAL ESTATE, sustainable farming is more labor intensive, because you simply cant send an omni-sprayer and an omni-chewer across the artificially flattened landscape. or, it will require robots that can walk around muddy tracks and hillsides and fields, pick tomatoes from the vine, carefully prune plants that need pruning, etc. y'know, the really hard stuff to automate.