Legume-nodule symbiosis is a natural partnership between leguminous plants and nitrogen-fixing bacteria that improves soil fertility. The bacteria, known as rhizobia, colonize the roots of legumes like beans, peas, and clover, forming nodules where they convert nitrogen from the air into a form that the plants can use for growth. In exchange, the legumes supply carbohydrates to the bacteria, creating a mutually beneficial relationship. This process reduces the need for synthetic fertilizers, lowering costs for farmers and minimizing environmental impact. By incorporating legumes into crop rotation systems, farmers can naturally replenish soil nitrogen levels, enhancing soil health and boosting productivity for subsequent crops, promoting a more sustainable and cost-effective farming approach.