Nitrogen cycle allows the various nitrogenous species to cycle among the inert nitrogen gas in the atmosphere and soil (Newton, 1999). According to Newton (1999), “the nitrogen gas molecule is fixed by either natural processes, which include both biological and non-biological (lightning, combustion and volcanism) systems, or man-made processes (mainly industrial ammonia production)” (p. 1). There are four processes in the nitrogen cycle, namely nitrogen fixation, decomposition, nitrification, and lastly, denitrification (refer to Figure 1 in Appendix 1). Firstly, the cycle involves nitrogen fixation. Nitrogen fixation is a process of forming ammonia (NH3) or nitrate (NO3-) from inorganic nitrogen in the atmosphere.
Nitrogen is released from microbial decay in the form of ammonium, but can also be immobilized by microbes which take up nitrate and ammonium to satisfy their own requirements. The mobilization or immobilization of nitrogen is dependent upon the amount of N the decomposing material itself provides; insufficient nitrogen released from decaying organic matter will result in the absorption of ammonium and nitrate by the microbes. An excess of N will satisfy the requirements of the microbes and provide a surplus to be released into the soil... ... middle of paper ... ...6-100. Campbell, C.A., V.O. Biederbeck, and F.G. Warder.
Falsey, 1994, Long-Term Tillage and Rotation Effects on Properties of a Central Ohio Soil: Soil Science Society of America Journal, 58: 517-522. Loomis, R.S. and D.J. Connor, 1992, Crop Ecology: Productivity and Management in Agricultural Systems: New York, Cambridge University Press, 538 p. Meek, B.D., D.L. Carter, D.T.Westermann, R.E.
Nitrogen fixation is the conversion of gaseous nitrogen to ammonia. This process is carried out my nitrogen-fixing bacteria in soil and aquatic environments. These bacteria find an enzyme called nitrogenase to break up molecular nitrogen and combine it with hydrogen. Nitrogen fixing bacteria must consume the energy in 12 grams of sugar in order to fix a single gram of nitrogen biologically. The second step, nitrification is the conversion of ammonia to nitrate.
Fertilizer... ... middle of paper ... ...ization efficiency of nitrogen, phosphorus, and potassium in wheat. Frontiers of Agriculture in China 5(3):253-61. Rush S., Gladilina E., Condy C., 2014. BIO A02S – Life on earth: form, function and interactions – Lab Manuel for Winter 2014. Toronto, Ontario: University of Toronto Scarborough Printing Services.
A daily basis, most organisms consume nitrogen in their food. It makes up about 80% of the atmosphere, but oxygen gas only covering 20% of the atmosphere. It can be condensed to liquid nitrogen. The boiling point of nitrogen is at a temperature of 195.8 m and freezes at -9. 209 m.... ... middle of paper ... ... the production of nitric acid and other chemicals.
When plants and animals eventually die, the nitrogen compounds are broken down giving ammonia (ammonification). Some of the ammonia is taken up by the plants; some is dissolved in water or held in the soil where bacteria convert it to nitrates (nitrification). Nitrates may be stored in humus or leached from the soil and carried to lakes and streams. It may also be converted to free nitrogen (denitrification) and returned to the atmosphere. The nitrogen cycle is one of the most difficult of the cycles to learn, simply because there are so many important forms of nitrogen, and because organisms are responsible for each of the introversions.