Nitrogen Cycle

• Nitrogen fixation is when nitrogen gass i nthe atmosphere is turned into ammonia by bacteria such as Rhizobium and Azobacter
• Rhizobium is found inside root nidukes of leguminous plants. They form a mutualistic relationship with the plants - they provide the plant with nitrogen compounds and the plant provides them with carbohydrates.
• Azobacter is found living in the soil. They don't form a mutualistic relationship with plants
• Ammonification is when nitrogen compounds from dead organisms are turned into ammonia by decomposers, which goes onto form ammonium ions.
• Animal waste also contains nitrogen compounds, There are also turned into ammonia by decomposers and go on to form ammonium ions.
• Nitrification is when ammonium ions in the soild are changed into nitrogen compounds that can be used by plants.
• Nitrosomonas changes ammonium ions into nitrites
• Nitrobacter changes nitrites into nitrates
• Denitrification is when nitrates in the soil are converted into nitrogen gas by denitrifying bacteria - they use nitrates in the saoik to carry out respiration and produce nitrogen gas
• Denitrification happens under anaerobic conditions such as in waterlogged soils