Nitrogen
All living organisms require nitrogen. Among other things, nitrogen helps make amino acids, proteins, nucleic acids, and DNA and RNA. In plants, it is essential for leaf development and making enzymes and chlorophyll that enable photosynthesis. Even though nitrogen is plentiful, making up 78% of the atmosphere, most plants cannot use it in this form. It must be ‘fixed’ into a compound with hydrogen. We discuss this process below.
Without sufficient nitrogen, plant growth is slow, water use is inefficient, and agricultural yields are low.
Phosphorus
Plants need phosphorus to support stem growth, root systems, flowers and seeds, and for disease resistance.
Potassium
Potassium is essential for photosynthesis. It regulates the stomata (or openings) in leaves that allow water, oxygen, and carbon dioxide to pass in and out of the plant. Potassium deficiency may cause necrosis (weak or dead spots), brown-spotting, and higher risk of attracting pathogens.
Common abbreviations for nitrogen, phosphorus and potassium are N, P, and K, respectively. They account for roughly 50%, 30% and 20% of inorganic fertilizers applied to agricultural crops. Wheat and corn each consume about 18% of total nitrogen-based fertilizers globally, with an additional 15% going to rice.