Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: The Noble Prophet (peace and blessings be upon him) wrote a letter to the people of Yemen. In this letter, he wrote to Harith Abdul Kallal and his other companions residing in Yemen, who belonged to Ma’afir and Hamdan:“Zakat on the produce of the land will be obligatory. From the land irrigated by springs and rainwater, payment of one-tenth will be obligatory, and from the land irrigated by buckets (i.e., by artificial means), payment of one-twentieth will be obligatory.”