It is narrated from Sayyiduna Abdullah (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) gave Khaybar to the Jews on the basis that "they would work it and cultivate it, and they would have half of what it produced."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المساقاة / 11630