1. Convert into nitric acid, nitrous acid, or nitrate, especially with the action of nitrobacteria
   "The bacteria nitrified the ammonia in the soil"
    
2. Treat with nitrogen or a nitrogen compound
   "They nitrified the soil to improve crop yield";
   - nitrogenize, nitrogenise [Brit]
    
3. Treat (soil) with nitrates
   "The farmers nitrified the soil to improve crop yields"

Derived forms: nitrified, nitrifies, nitrifying

Type of: convert, enrich, feed, fertilise [Brit], fertilize, process, treat

Antonym: denitrify