dirt vs old sod

dirt

noun
  • Meanness; sordidness. 

  • A stain or spot (on clothes etc); any foreign substance that worsens appearance. 

  • Previously unknown facts, or the invented "facts", about a person. 

  • In placer mining, earth, gravel, etc., before washing. 

  • freckles 

  • Soil or earth. 

verb
  • To make foul or filthy; soil; befoul; dirty 

old sod

noun
  • Used other than figuratively or idiomatically: see old, sod (person). 

  • The old country; one's place of origin. 

How often have the words dirt and old sod occurred in a corpus of books? (source: Google Ngram Viewer )