Musnad Ahmad 33:1084

Abu Mu'awiyah narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever plants a plant or sows a crop, and a human, or a bird, or a beast of prey, or an animal eats from it, then it is for him a charity."