River crabs enrich rice fields in northeast China

In China's Jilin province, rice farmers in the northeastern city of Songyuan are harvesting more per acre, and as a result, are earning more money by breeding river crabs in their fields. Rice paddies provide an ideal habitat to protect crabs from predators, while crabs in turn feed on weeds and insects that may harm rice seedlings. Crabs also loosen the soil when they move around, and their excrement can enrich organic matter content in the soil.