Nitrogen in Soil and the Environment

Nitrogen is the seventh most abundant element in the universe. It’s the single most common element in the earth’s atmosphere, comprising about 78% (4,000 trillion tons) of the gas that makes up our atmosphere. Nitrogen is found in all soils, and is required by all living creatures. In plants, nitrogen is the nutrient required in the largest amounts. It is a key constituent of critical organic molecules such as amino acids, nucleic acids, and proteins. Nitrogen is found in marine and freshwaters and is present in some minerals. In short, nitrogen is found in every ecosystem and in every part of the global environment. This handout provides an overview of the chemistry and biology of soil nitrogen, nitrogen fertilizers, and nitrogen management.