Dawud bin Sulayman (may Allah have mercy on him) said: Umar bin Abd al-Aziz (may Allah have mercy on him) wrote a letter to Abd al-Hamid bin Abd al-Rahman (may Allah have mercy on him), in which it was written that there is no kharaj on the land of one who accepts Islam; and there is a musnad narration: "Only zakah is due on him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18409