Legume plants play a crucial role in nitrogen fixation, a process that converts atmospheric nitrogen (N₂) into ammonia (NH₃) that plants can use. This occurs through symbiotic relationships with bacteria, such as Rhizobium, which live in nodules on the roots of legumes. The bacteria convert nitrogen gas from the atmosphere into ammonia, providing an essential nutrient for legumes, while receiving carbohydrates and a protective environment in return. This mutualistic relationship enhances soil fertility, making legumes important in agriculture and sustainable farming practices, allowing for increased crop yields and reduced need for chemical fertilizers.