Narrated Ibn 'Umar (RA):

Allah's Messenger (ﷺ) had agreed with the people of Khaibar to give (to the Muslim authority) half what it produced of fruits or crops. [Agreed upon].

عَنْ اِبْنِ عُمَرَ ‏-رَضِيَ اَللَّهُ عَنْهُمَا‏-; { أَنَّ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-عَامَلَ أَهْلَ خَيْبَرَ بِشَطْرِ مَا يَخْرُجُ مِنْهَا مِنْ ثَمَرٍ, أَوْ زَرْعٍ } مُتَّفَقٌ عَلَيْهِ [1]‏ .‏