Why is the nitrogen cycle important?
The nitrogen cycle reflects a more intimate side of energy needs, via its central role in the production of food. It is one of the places where the chemistry of the Earth and life come together, as plants extract nitrogen from their environment, including the air, to make food. Controlling the impact of agriculture on the global cycle of nitrogen is a growing challenge for sustainable development. Nitrogen is an essential component of amino acids (the building blocks of proteins) and of nucleotides (the building blocks of DNA), and consequently is needed by all living things. Fortunately, the planet’s supply of nitrogen is inexhaustible — it is the main element in the air, making up nearly four-fifths of the atmosphere in the form of nitrogen molecules, each composed of two nitrogen atoms. Unfortunately, that nitrogen is not readily available for use by living organisms, as the molecules do not easily enter into chemical reactions. In nature, breaking up nitrogen requires energy on the