Nitrogen Cycle. Magic book. Magic glares. Atmospheric Nitrogen. Mr. Smart. I constitute around 78% of the air. It’s time for Nitrogen Cycle. Leguminous Plant. Atmospheric nitrogen cannot be used directly by plants and animals. Nitrogen needs to get converted to nitrogenous compounds. This process is called Nitrogen fixation. So, go to my roots. Leguminous plant roots. Root nodules. Rhizobium House. Hi, I am Rhizobium bacterium. I live in the root nodules of leguminous plants. I am going to convert nitrogen to ammonia. Ammonia. Ammonia. Hello, we are Nutrifying bacteria. We are going to convert ammonia to nitrites and then nitrates. Nitrates. Nitrogen fixation can also occur by lightning strikes. Nitrogenous compounds. Nitrates. Plants take these nitrates from the soil. Plants use these nitrates to make proteins. Animals eat plants to get proteins. Dead plants and animal excreta contain nitrogenous wastes. Overtime, these wastes decay and ammonia is released. Ammonia. Nutrifying bacteria. Ammonia again gets converted to nitrates. Nitrates. Some nitrates are again used by plants. NItrates. Denitrifying bacteria. Hello, we are going to convert these nitrates back to atmospheric nitrogen. NItrogen gas goes back to atmosphere. Hence, my percentage in air remains constant. Atmospheric nitrogen. Rhizobium. Ammonia. Nutrifying bacteria. Nitrates. Lightning strike. Nitrates. Plants absorb nitrates to make proteins. Animals eat plants to get proteins. NItrogenous wastes. Decay. Ammonia. Nitrifying bacteria. Nitrates. Denitrifying bacteria. Atmospheric nitrogen. This cycle is known as Nitrogen Cycle. The End.