Sayyiduna Anas (may Allah be pleased with him) said that: "And give its due on the day of its harvest." [Surah al-An'am: 141] refers to zakah, and both of these (reports) are mawquf (stopping at the Companion) and not strong.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7502