Nitrogen cycle

This is the process in which nitrogen is converted between its various chemical forms. The conversion can be carried out, both in the form of biological and physical processes. The vital processes in the completion of nitrogen cycle include fixation, nitrification, denitrification and ammonification. The main component of the nitrogen cycle starts with the element of nitrogen in the air. Two nitrogen oxides are found in the air as a result of interactions with oxygen. Nitrogen only reacts with oxygen in the presence of high temperatures and pressures found near lightning flash and in combustion reactions in power plants or internal combustion engines. Nitric oxide, NO, and nitrogen dioxide, NO2, are formed under these conditions.

 

Nitrogen in the atmosphere becomes a part of biological matter mostly through the actions of bacteria and algae in a process known as nitrogen fixation. Legume plants like clover, alfalfa, and soybeans form nodules on the roots where nitrogen fixing bacteria takes nitrogen from the air and convert it into ammonia, NH3. The ammonia is then transformed by other bacteria first into nitrite ions, NO2-, and after which into nitrate ions, NO3-. Plants make use of the nitrate ions as a nutrient or fertilizer for its growth.

Human activities such as the use of artificial nitrogen fertilizers, fossil fuel combustion and the release of nitrogen in waste-water have technically altered the global nitrogen cycle.

Nitrogen cycle