Messenger of Allah ﷺ handed over the land of Khaibar (on the condition) of the share of produce of fruits and harvest, and he also gave to his wives every year one hundred wasqs: eighty wasqs of dates and twenty wasqs of barley. When 'Umar became the caliph he distributed the (lands and trees) of Khaibar, and gave option to the wives of Allah's Apostle ﷺ to earmark for themselves the land and water or stick to the wasqs (that they got) every year. They differed in this matter. Some of them opted for land and water, and some of them opted for wasqs every year. 'A'isha and Hafsa were among those who opted for land and water.  

أَعْطَى رَسُولُ اللَّهِ ﷺ خَيْبَرَ بِشَطْرِ مَا يَخْرُجُ مِنْ ثَمَرٍ أَوْ زَرْعٍ فَكَانَ يُعْطِي أَزْوَاجَهُ كَلَّ سَنَةٍ مِائَةَ وَسْقٍ ثَمَانِينَ وَسْقًا مِنْ تَمْرٍ وَعِشْرِينَ وَسْقًا مِنْ شَعِيرٍ فَلَمَّا وَلِيَ عُمَرُ قَسَمَ خَيْبَرَ خَيَّرَ أَزْوَاجَ النَّبِيِّ ﷺ أَنْ يُقْطِعَ لَهُنَّ الأَرْضَ وَالْمَاءَ أَوْ يَضْمَنَ لَهُنَّ الأَوْسَاقَ كُلَّ عَامٍ فَاخْتَلَفْنَ فَمِنْهُنَّ مَنِ اخْتَارَ الأَرْضَ وَالْمَاءَ وَمِنْهُنَّ مَنِ اخْتَارَ الأَوْسَاقَ كُلَّ عَامٍ فَكَانَتْ عَائِشَةُ وَحَفْصَةُ مِمَّنِ اخْتَارَتَا الأَرْضَ وَالْمَاءَ