The Southern colonel is based off the character Senator Claghorn of The Fred Allen Show. His white outfit, the pocket watch and cigars in his breast pocket resemble Claghorn's, and when he shows up at the Simpsons' house to duel, he says "Sir, I say sir!" much like Claghorn would. He also has a similar accent. Claghorn's voice and mannerisms also inspired the Warner Bros. character Foghorn Leghorn
The Southern colonel's RV has mudflaps of him drawn like Yosemite Sam.
The scene with Homer worrying about the duel the next morning whilst looking at a tombstone with his own name on it spoofs the 1990 film Back to the Future Part III.
The death of the Laramie team in the helicopter, at the hands of a ToMacco-crazed sheep, is a nod to a scene in the James Cameron film Aliens, where the crew of the marines' drop-ship meet the same fate, when an alien sneaks aboard their ship.
The title is an obvious reference to children's nursery rhyme, Old Macdonald line (E-I-E-I-O).
The scene with Lenny and Carl around the water cooler is a nod to Dilbert.
Plutonium is shown as a glowing green liquid even though it is a dull silver metal with a melting point of 1183 degrees Fahrenheit. However, radioactive materials are often depicted as glowing green in popular culture and on The Simpsons.
When Homer thinks he's catching some invisible so-called plants, this was brought up on 5 November 2004 when the Simpsons was moved from BBC Two to Channel 4 in the UK showing Homer thinking he's catching a Channel 4 logo surrounded by a flash of colored lights. See here from 0:30 to 0:50.
When the opening credits are updated for HD, One of the items Marge buys is a bottle of Tomacco Juice.
Running Gag: Homer's tractor rolling over and crushing his legs.
Homer's house he grew up in on Rural Route 9 burned down in the episode "Grampa vs. Sexual Inadequacy" (season 6), yet it is still there in this episode. One of the official Simpsons episode guide books, The Simpsons Beyond Forever!: A Complete Guide to Our Favorite Family ...Still Continued, claims that this episode must take place before the season 6 episode or the house didn't burn down as badly as depicted.
The store owner said that Abe abandoned the farm because nothing would grow, but in "Grampa vs. Sexual Inadequacy" it was said that the bank foreclosed the farm because the cows gave sour milk due to Homer scaring them.