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Why is ammonia widely used as a fertilizer?

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Difference in molecular structure between ammonia/amines and quaternary ammonium ions — ammonia Ammonia and amines have a slightly flattened trigonal pyramidal shape with a lone pair of electrons above the nitrogen. In quaternary ammonium ions, this area is occupied by a fourth substituent.

Ammonia is widely used as a fertilizer because it is a vital source of nitrogen, an essential element for plant growth. Although nitrogen gas makes up 78 percent of the atmosphere, most organisms cannot use it in that form; plants require nitrogen specifically in the form of nitrate or ammonium ions to synthesize the proteins and nucleic acids necessary for life.123

Modern agricultural practices rely on ammonia-based fertilizers to replenish soil nutrients, especially in areas of intensive farming where crops are harvested frequently. The industrial production of ammonia is primarily achieved through the Haber-Bosch process, which synthesizes ammonia from nitrogen and hydrogen at high pressures.24

Once produced, ammonia can be applied directly to the soil as a liquefied gas or converted into solid nitrogenous products such as ammonium nitrate, ammonium sulfate, ammonium phosphates, and urea. These compounds are easily absorbed by plants, making them highly effective for supporting agricultural yields.12