cultivate vs impoverish

cultivate

verb
  • To turn or stir soil in preparation for planting. 

  • To nurture; to foster; to tend. 

  • To grow plants, notably crops. 

impoverish

verb
  • To make poor. 

  • To become poor. 

  • To weaken in quality; to deprive of some strength or richness. 

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