Intercropping mung beans with rice serves two purposes. The mung bean is a valuable source of protein and when grown on the path that divides the rice paddies it controls erosion because the mung bean has an extensive root system that binds the soil. The grass that grows on the divide will also be cut and fed to fish and livestock. The grass is not fed to pigs as pigs require most plant matter to be cooked due to their digestive system.