Farmers pick mushrooms at a mushroom production base in Fucheng County, north China's Hebei Province, April 1, 2018. Local agriculture authorities are encouraging farmers to grow greenhouse mushrooms in spring and autumn as a more profitable alternative to winter-grown mushrooms. (Xinhua/Li Xiaoguo)

A farmer picks mushrooms at a mushroom production base in Fucheng County, north China's Hebei Province, April 1, 2018. Local agriculture authorities are encouraging farmers to grow greenhouse mushrooms in spring and autumn as a more profitable alternative to winter-grown mushrooms. (Xinhua/Li Xiaoguo)

A farmer picks mushrooms at a mushroom production base in Fucheng County, north China's Hebei Province, April 1, 2018. Local agriculture authorities are encouraging farmers to grow greenhouse mushrooms in spring and autumn as a more profitable alternative to winter-grown mushrooms. (Xinhua/Li Xiaoguo)