Nitrogen (N) is essential for photosynthesis. It is also the basic element of plant and animal proteins, including the genetic material DNA and RNA, and is important in periods of rapid plant growth. Plants use nitrogen by absorbing either nitrate or ammonium ions through the roots.

Phosphorus (P) is essential for all living organisms. Plants must have it for normal growth and maturity. Phosphorus plays a role in photosynthesis, respiration, energy storage and transfer, cell division, cell enlargement and several other processes in plants.

Complex/mixed fertilizers contain multiple nutrients, mixed together to achieve a desired average nutrient composition. This allows farmers to spread them to eliminates the potential for segregation of nutrient sources during transport or application.

Ammonium nitrate, a salt of ammonia and  nitric acid, used widely in fertilizers. The commercial grade contains about 33.5 percent nitrogen, all of which is in forms utilizable by plants; it is the most common nitrogenous component of artificial fertilizers.