If he's going to build it over farmland, whether he uses solar panels or not is irrelevant to the farm. The land would be rented/bought/imminent domained just like normal rail would.
He makes the point that he doesn't need to block 100 feet from each side of the track, as well as put barriers in place to prevent animal crossing and blocking farmers from getting to the other side of the farm, in the same way power lines today use space. That means he would need some non-farmable area around the track, yes, but that it wouldn't disrupt the farm like a normal HSR track would.
