The concept of a "bushel of wheat for a barrel of oil", arose out of the dramatic oil price rises starting in 1973. The concept gained a lot of traction by farm groups and was even a topic of a Federal Reserve paper(in 1981) looking at a grain cartel by the US.

From the paper....

"OPEC’s actions in raising oil prices and restricting production have given rise to numerous proposals designed to offset the higher petroleum costs. One widely discussed proposal has been for the United States to organize a grain cartel that would significantly raise grain prices to the OPEC nations. Many suggest that the terms of trade between the two cartels should be a bushel of wheat for a barrel of oil, i.e., about the same terms that prevailed in early 1973 when wheat sold for about $2 per bushel and imported oil sold for about $2 per barrel"




 https://files.stlouisfed.org/research/publications/review/81/04/Bushel_Apr1981.pdf