waht is a nitrogen cycle?

Question

i need it for my assignment

Answer 1

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Nitrogen Cycle: The nitrogen cycle describes the many forms that nitrogen takes in our environment, and the pathways in which nitrogen is altered from species to species. Nitrogen is removed from the cycle temporarily when it is incorporated into the bodies of plants and animals, and when it is leached into the soils, returning eventually as organic nitrogen.

The main component of the nitrogen cycle starts with the element nitrogen in the air. Two nitrogen oxides are found in the air as a result of interactions with oxygen. Nitrogen will only react with oxygen in the presence of high temperatures and pressures found near lightning bolts and in combustion reactions in power plants or internal combustion engines. Nitric oxide, NO, and nitrogen dioxide, NO2, are formed under these conditions. Eventually nitrogen dioxide may react with water in rain to form nitric acid, HNO3. The nitrates thus formed may be utilized by plants as a nutrient.

Nitrogen in the air becomes a part of biological matter mostly through the actions of bacteria and algae in a process known as nitrogen fixation. Legume plants such as clover, alfalfa, and soybeans form nodules on the roots where nitrogen fixing bacteria take nitrogen from the air and convert it into ammonia, NH3. The ammonia is further converted by other bacteria first into nitrite ions, NO2-, and then into nitrate ions, NO3-. Plants utilize the nitrate ions as a nutrient or fertilizer for growth. Nitrogen is incorporate in many amino acids which are further reacted to make proteins.

Ammonia is also made through a synthetic process called the Haber Process. Nitrogen and hydrogen are reacted under great pressure and temperature in the presence of a catalyst to make ammonia. Ammonia may be directly applied to farm fields as fertilizer. Ammonia may be further processed with oxygen to make nitric acid. The reaction of ammonia and nitric acid produces ammonium nitrate which may then be used as a fertilizer. Animal wastes when decomposed also return to the earth as nitrates.

To complete the cycle other bacteria in the soil carry out a process known as denitrification which converts nitrates back to nitrogen gas. A side product of this reaction is the production of a gas known as nitrous oxide, N2O. Nitrous oxide, also known as "laughing gas" - mild anesthetic, is also a greenhouse gas which contributes to global warming.

Answer 2

Nitrogen in the air is chemically combined by soil microbes to make nitrogen compounds which are ingested by plants. Legumes such as peas and soybeans are particularly useful for this. The nitrogen compounds are used to make proteins, which help the plant (and anything that eats it) grow. The proteins may be incorporated in the body of the eater, or degraded, releasing nitrogen compounds (such as urea) back to the environment. Microbes break this down into nitrogen, returning it to the atmosphere.

Answer 3

Check this link.....
http://en.wikipedia.org/wiki/Nitrogen_cycle

Answer 4

good question, when you find out tell me. it sounds really interesting. good luck