Salim narrates from Sa'id bin Jubayr (may Allah have mercy on him) that the saying of Allah, the Exalted: "And give its due on the day of its harvest." [Surah al-An'am: 141] was from before zakah; when the verse of zakah was revealed, it was abrogated. He said: One would give a bundle (dighth) from it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7509