Facts about the Nitrogen Cycle

1. 06

   Plant roots absorb nitrate and ammonium ions from soil, incorporating nitrogen into amino acids and proteins through assimilation, which represents the critical entry point of inorganic nitrogen into the food web.

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2. 05

   Nitrification, the two-step microbial conversion of ammonia to nitrate through Nitrosomonas and Nitrobacter bacteria, occurs in most soils and is essential for plant nitrogen availability.

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3. 04

   Ammonia production via the Haber-Bosch process, developed in 1909, now supplies approximately 80 percent of all nitrogen used in global agriculture through synthetic fertilizers.

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4. 03

   Legume plants form symbiotic relationships with Rhizobium bacteria in root nodules, fixing approximately 100-290 million metric tons of atmospheric nitrogen annually for agricultural use.

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5. 02

   Denitrifying bacteria in anaerobic soils and water convert nitrate back to nitrogen gas, returning approximately 100-290 million metric tons annually to the atmosphere.

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6. 01

   Atmospheric nitrogen fixation by lightning, soil bacteria, and industrial processes converts approximately 200 million metric tons of N2 annually into usable compounds.

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