Nitrogen+Cycle

More importantly - why is nitrogen important?
Source - //http://www.ehow.com/about_4609019_why-nitrogen-important-living-things.html//

Life depends on nitrogen, which is a basic ingredient in amino acids that make up all proteins. While a substantial percentage of the atmosphere is comprised of nitrogen gas, it must be processed into a soluble form. This is done via a nitrogen cycle that occurs in the soil. Then plants and the animals that eat them can obtain dietary nitrogen.

Significance

 * Plants with nitrogen deficiencies look weak. The leaves, which should be healthy and green, may look wilted and yellow. Animals and people get dietary nitrogen by eating protein-rich foods like milk, eggs, fish, beef and legumes. Nitrogen, carbon, hydrogen and oxygen are found in amino acids, which are the main structures of every protein.

Function

 * Though 78 percent of the atmosphere is made of inert nitrogen, it must be transformed into a form that can be used by plants and animals. This happens via a nitrogen cycle that occurs in the soil. Earthworms, bacteria and other forces break down the proteins in organic material and animal manure in the soil to decompose them. The first byproduct is ammonia, a compound of nitrogen and hydrogen. Next, nitrates are formed. Nitrobacteria called azotobactors produce soluble nitrates that plants can get out of the soil.

