Al-Hakam (may Allah have mercy on him) narrates from Qadi Shurayh (may Allah have mercy on him) that he bought land of al-Hirah called Zuba, and there was a concession for buying the land of al-Hirah because it was land of a peace treaty. (b) Yahya (may Allah have mercy on him) said: I asked Hasan bin Salih (may Allah have mercy on him), and he disliked buying kharaj land which was taken by fighting and on which kharaj was imposed, and saw no harm in buying land of a peace treaty.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18408