Musnad Ahmad 32:1609

Surayj narrated to us, Abu 'Awanah narrated to us, from Qatadah, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no Muslim who plants a plant, or sows a crop, and then a bird, or a human, or an animal eats from it, but it will be a charity for him."