Peanut, also known as
groundnut (
Arachis hypogaea), is a crop of global importance. It is widely grown in the
tropics and subtropics, being important to both smallholder and large commercial producers. It is classified as both a grain
legume, and, because of its high oil content, an oil crop. World annual production is about 46 million
tonnes per year. Very unusual among crop plants, peanut pods develop under the ground. As a legume, peanut belongs to the botanical
family Fabaceae (also known as
Leguminosae, and commonly known as the bean or pea family). Like most other legumes, peanuts harbor
symbiotic nitrogen-fixing bacteria in
root nodules. This capacity to fix nitrogen means peanuts require less nitrogen-containing
fertilizer and improve
soil fertility, making them valuable in
crop rotations.