Hazrat Hakam (may Allah have mercy on him) narrates that Hazrat Umar bin Khattab (may Allah be pleased with him) sent Uthman bin Hunaif (may Allah have mercy on him) to the wealthy people. So he fixed one dirham and one qafiz of wheat or barley on every cultivated and uncultivated land that is irrigated by water. And he fixed ten each on every vineyard. And he fixed five on vegetable crops.