Nitrogen Cycle & Nitrogen Fixation

A power-point presentation of Nitrogen Cycle and Nitrogen Fixation

1. NITROGEN CYCLE & NITROGEN FIXATION Done by Saquib ahmed

2. Nitrogen Cycle Nitrogen cycle is a natural cyclic process in which it becomes a part of the living organisms, before it is sent back to the atmosphere. The nitrogen cycle represents one of the most important nutrient cycles found in terrestrial ecosystems. Nitrogen is used by living organisms to produce a number of complex organic molecules like amino acids , proteins , and nucleic acids .

3. AMMONIFICATION Ammonification or Mineralization is performed by bacteria to convert the ammonia to ammonium. Nitrification can then occur to convert the ammonium to nitrite and nitrate This process liberates a lot of energy which can be used by the saprotrophic microbes

4. NITRIFICATION Nitrification is the process by which ammonia is converted to nitrites and then nitrates. This process naturally occurs in the environment, where it is carried out by specialized bacteria. This energy is the only source of energy for these prokaryotes They are chemoautotrophs Chemoautotroph is an organism, typically a bacterium, which derives energy from the oxidation of inorganic compounds. Prokaryote is a microscopic single-celled organism which has neither a distinct nucleus with a membrane nor other specialized organs.

5. Nitrogen from atmosphere Out gassing Atmospheric fixation Root uptake Nitrate NO 3 - Plant protein Soil organic nitrogen Atmospheric Nitrogen Biological fixation

6. Atmospheric nitrogen fixation Electrical storms Lightning provides sufficient energy to split the nitrogen atoms of nitrogen gas, Forming oxides of nitrogen NO and NO 2

7. Atmospheric pollution This also happens inside the internal combustion engines of cars The exhaust emissions of cars contribute a lot to atmospheric pollution in the form of NO x These compounds form photochemical smog They are green house gases They dissolve in rain to contribute to acid rain in the form of nitric acid The rain falling on soil and running into rivers They contribute to the eutrophication of water bodies No x are oxides of nitrogen, especially as atmospheric pollutants

8. conclusion Adding nitrate fertiliser clearly helps the growth of plants The presence of microbes permits the peas to grow much better. The peas grow better in the presence of the microbes than they do with nitrate fertiliser added The difference is due to the present of mutualistic nitrogen fixing bacteria which live in the pea roots. Mutualism is the way two organisms of different species exist in a relationship in which each individual benefits. Similar interactions within a species are known as co-operation.

9. The nitrogen fixers Cyan bacteria are nitrogen fixers that also fix carbon (these are photosynthetic). Rhizobium bacteria are mutualistic with certain plant species e.g. Legumes. They grow in root nodules. Azotobacter are bacteria associated with the rooting zone (the rhizosphere) of plants in grasslands.

10. Alafalfa ( Medicago sativa)

11. The human impact Nitrate NO 3 - Atmospheric fixation Out gassing Plant protein Atmospheric Nitrogen Ammonium NH 4 + Soil organic nitrogen Biological fixation

12. Making things better The need for synthetic fertilisers can be reduced by cultural practices Avoiding the use of soluble fertilisers in soil prevents leaching Rotating crops permits the soil to recover from nitrogen hungry crops (e.g. wheat) Adding a nitrogen fixing crop into the rotation cycle Ploughing aerates the soil and reduces denitrification Draining water logged soil also helps reduce denitrification

13. PRESENTATION BY:- PRIY@NSHU SRINIV@S@N M@NIDEEP N.SM@MY S@QUIB HUSTLE.LOYALTY.RESPECT