Understanding the soil nitrogen cycle

The Internal Nitrogen Cycle Betweenmicroorganisms,vegetationand Soil

The major portion of the global nitrogen cycle occurs between vegetation and soil, only minor exchanges generally taking place with the atmosphere and the hydrosphere. Nitrogen conversions in soil are briefly reviewed and a global flow chart for soil nitrogen is presented. The turnover times of nitrogen in various components of this global system are compared with its turnover times in some sel...

A chronology of human understanding of the nitrogen cycle.

Nitrogen over the ages! It was discovered in the eighteenth century. The following century, its importance in agriculture was documented and the basic components of its cycle were elucidated. In the twentieth century, a process to provide an inexhaustible supply of reactive N (Nr; all N species except N2) for agricultural, industrial and military uses was invented. This discovery and the extens...

Plant-Soil-Microorganism Interactions on Nitrogen Cycle: Azospirillum Inoculation

The Global Nitrogen Cycle

The geobiology of nitrogen is dominated by large inert reservoirs and small biological fluxes. The largest reservoirs are nitrogen gas (in the atmosphere and dissolved in the ocean) and sedimentary nitrogen (sequestered in continental crust). Because most organisms cannot utilize gaseous nitrogen, we distinguish between fixed nitrogen compounds (which contain no N–N bonds) that are biologically...

The microbial nitrogen cycle

Nitrogen (N) is an essential element in biological systems and one that often limits production in both aquatic and terrestrial systems. Due to its requirement in biological macromolecules, its acquisition and cycling have the potential to structure microbial communities, as well as to control productivity on the ecosystem scale. In addition, its versatile redox chemistry is the basis of comple...