Nitrogen is required by plants in the largest amounts of the three major (macro) nutrients: nitrogen, phosphorus, and potassium.
Nitrogen is a part of all living cells and is a requisite of the metabolic processes in which proteins, amino acids, coenzymes, and nucleic acids are created.
It is an integral part of chlorophyll manufacture through photosynthesis, the process in which light energy is utilized to convert carbon dioxide into carbohydrates, which is in turn used to provide the energy for growth and development.