Fee-fi-fo-fum,

I smell the blood of an Englishman,

Be he alive, or be he dead

I'll grind his bones to make my bread.

But apparently not limited to the English, and for fertilizer, which grew the grain, but surprisingly accurate otherwise.

Wasn't it "I smell the blood of a Christian" (presumably as opposed to a "Turk" or "Moor")

According to Wikipedia (never wrong!) it was known as early as 1596 with "Englishman" https://en.wikipedia.org/wiki/Fee-fi-fo-fum

TIL the Celtic etymology of the first line.