Legumes are plants that produce pods, which are the simple dry fruit. Popular legumes include peanuts, soy, lentils, peas and beans. Legumes have been cultivated since the earliest times of agriculture in Asia, the Americas and Europe.
Due to a mutualistic symbiotic relationship between legumes and rhizobia bacteria inhabiting the root nodules of the plant, legumes are able to fix atmospheric nitrogen in the soil. So planting legume means farmers do not have to fertilise their soil as much as they would other plants.