It absolutely was an accounting trick, done in the name of TV ratings. This is Jeremy Clarkson - he's a TV personality and things done on his TV shows are not to be taken seriously.
The farm had a grain business, sheep, a farm store for veg and stuff, and grants from government for re-naturing part of the property. I have no idea how Clarkson calculated the 144 profit, but I suspect there was a lot of shenanigans do arrive at that number for effect.
Edit - I'll add that I enjoyed the show. While obviously done for shock value (similar vein as as Top Gear and Grand Tour), it did a reasonable job showing how complicated and expensive running a farm can be.
The farm had a grain business, sheep, a farm store for veg and stuff, and grants from government for re-naturing part of the property. I have no idea how Clarkson calculated the 144 profit, but I suspect there was a lot of shenanigans do arrive at that number for effect.
Edit - I'll add that I enjoyed the show. While obviously done for shock value (similar vein as as Top Gear and Grand Tour), it did a reasonable job showing how complicated and expensive running a farm can be.