For the purposes of this Act, the owner of agricultural land shall be deemed to fulfil his responsibilities to manage it in accordance with the rules of good estate management in so far as his management of the land and (so far as it affects the management of that land) of other land managed by him is such as to be reasonably adequate, having regard to the character and situation of the land and other relevant circumstances, to enable an occupier of the land reasonably skilled in husbandry to maintain efficient, sustainable and regenerative production as respects both the kind of produce...