Musannaf Ibn Abi Shayba 28:502

Abu Mu'awiyah narrated to us, from al-Shaybani, from Muhammad ibn 'Ubayd Allah al-Thaqafi, who said: A man from Thaqif, who was called Nafi' Abu 'Abd Allah, came to 'Umar. He said: And he was the first to cultivate uncultivated land in Basra. He said: So he said, "O Commander of the Faithful, we have land before us in Basra that is not from the land of *kharaj* (land tax), and it does not harm any of the Muslims. If you see fit to grant it to me so that I may cultivate fodder for my horses, then do so." He said: So 'Umar wrote to Abu Musa, "If it is as he said, then grant it to him."