NITROGEN AND NITROGEN CYCLE
WHAT IS NITROGEN? Nitrogen is one of the essential constituents of all living organisms as part of proteins, chlorophyll, acids and vitamins. Nitrogen covers up to 78% of the atmosphere of the earth. It is the most plentiful (in a large amount.) gas in the air. When we inhale, we take some amount of nitrogen into our lungs and exhale it. But plants need nitrogen for their survival. They cannot take nitrogen directly from the air. A bacterium, which lives in the soil and roots of some plants, take nitrogen from the air and changes its form so that plants can use it. The name of this bacterium is Rhizobium . NITROGEN FIXATION Rhizobium bacteria are involved in the fixation of nitrogen in leguminous plants (pulses). Recall that Rhizobium lives in the root nodules of leguminous plants such as beans and peas, with which it has a symbiotic relationship. Sometimes nitrogen gets fixed through the action of lightning. But you know that the amount of...