Legumes enrich soil by adding nitrogen to it through their what?

Legumes enrich soil by adding nitrogen through their root nodules, which house nitrogen-fixing bacteria, such as Rhizobium. These bacteria convert atmospheric nitrogen into a form that plants can use, effectively increasing the nitrogen content in the soil. As legumes grow and decompose, they release this nitrogen back into the soil, enhancing its fertility for subsequent crops. This symbiotic relationship benefits both the legumes and the surrounding ecosystem.