>>3871439No, it think it's shown in the second last(?) or last episode of Farmland. He had an argument with Olmar where Olmar eventually revealed that he intended to take over the farm, size it down and give the rest to the families that lost their fathers and sons because of the war. He was inspired by Throfinn and this is what told Thorkell that there was no place for him on the farm anymore.
Throughout the arc it was it was his goal to teach his brother how to become a proud man who is able to fight and kill to restore his family's honor, but this development made it clear that Olmar will never be like him and after having lost his job under Knut he believed he had no choice but to leave. He is too proud and angry to return to Knut and he will never be able to settle down and become a farmer.