The riff: Addressed to the screen by Servo as the name of “educational collaborator” Reuben Hill is shown.
The explanation: Tom is referring to a song from the early career of country icon Kenny Rogers, back when he was leading a band called The First Edition. The song, “Reuben James,” is about a black sharecropper who is unfairly targeted for abuse in his small town, and was a modest hit in 1969. Tom actually misquotes the lyrics though, because as written, it’s “walk the furrowed fields of my mind.”
Novelty factor: I’ve never heard the song before now.