A farmer shows crabs raised in rice paddies at a farm in the Caofeidian District of Tangshan, north China's Hebei Province, July 28, 2018. For years, the farm in Tangshan has stuck to a mixed farming mode which effectively boosted economic yields by raising crabs together with organic rice. (Photo: Xinhua) 

A farmer shows crabs raised in rice paddies at a farm in the Caofeidian District of Tangshan, north China's Hebei Province, July 28, 2018. For years, the farm in Tangshan has stuck to a mixed farming mode which effectively boosted economic yields by raising crabs together with organic rice.(Photo: Xinhua) 

Crabs are raised in a rice paddy at a farm in the Caofeidian District of Tangshan, north China's Hebei Province, July 28, 2018. For years, the farm in Tangshan has stuck to a mixed farming mode which effectively boosted economic yields by raising crabs together with organic rice. (Photo: Xinhua)