The Book of Zakah
23/42. Chapter:
Barley
Sunan an-Nasai
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا دَاوُدُ بْنُ قَيْسٍ، قَالَ حَدَّثَنَا عِيَاضٌ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ كُنَّا نُخْرِجُ فِي عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم صَاعًا مِنْ شَعِيرٍ أَوْ تَمْرٍ أَوْ زَبِيبٍ أَوْ أَقِطٍ فَلَمْ نَزَلْ كَذَلِكَ حَتَّى كَانَ فِي عَهْدِ مُعَاوِيَةَ قَالَ مَا أَرَى مُدَّيْنِ مِنْ سَمْرَاءِ الشَّامِ إِلاَّ تَعْدِلُ صَاعًا مِنْ شَعِيرٍ .
It was narrated that Abu Sa' eed Al-Khudri said: "At the time of the Messenger of Allah, we used to give a Sa' of barley, or dates, or raisins, or cottage cheese, and we continued to do so until the time of Mu'awiyah, when he said: 'I think that two Mudds of wheat from Ash-Sham are equivalent to a Sa' of barley."'
Reference : Sunan an-Nasa'i 2517In-book reference : Book 23, Hadith 83English translation : Vol. 3, Book 23, Hadith 2519