Seek I don't believe Rob gives a damn one way or the other about organic production!
Rob has been driven out of his inheritance. Whether that was his own fault or whether Miles is the golden child we cannot yet tell. But everything he does is motivated by a desire to have revenge on life and establish a new kingdom.
I said in a past thread that he might have found Canada less painful because his status would have been blurry there. But I imagine it would also have been easier for him, in the midst of mega-farming and with no close ties to any community, to disguise to himself (or at least shove to the back of his mind) the fact that he had nothing of his own.
Ambridge would be the worst possible place for someone with his ... is pathology the right word? A place where everyone lives closely tied to family and to their own land or connection to land. And everyone is respected for their place in the landscape. Look how venemous he's been towards "village girls who struck lucky" - he saw them with more status and stake in the community than he had with all his big salary. If, on their return from Canada, he and Jess had gone to a big, anonymous city he'd have been much happier and less intent on destroying other people to further his own aims. (He would still have been an evil colleague but would have had less scope to take over entire families.)
Sending Tom to Canada was definitely an early, bold attempt to userp a prince of the land.
What was my point again ...? Oh yes, something about him not acting based on any firmly held principles but purely on animal instinct ...