If a fixed, measured kharaj were instituted anew in a newly established district, the measures customary among its people would be observed, using the recognized qafiz measures of that district.

In the early days of Persian rule, the Sawād was subject to crop-sharing until Qubādh ibn Fīrūz imposed a kharaj upon it. It yielded 150 million dirhams according to the mithqāl weight. The Persians maintained this assessment for the remainder of their rule.

When Islam came, ʿUmar retained the system, assessing the land by acreage and kharaj. During his time, its kharaj reached 120 million dirhams. Ziyād collected 125 million, while ʿUbayd Allāh ibn Ziyād collected 135 million. Al-Ḥajjāj collected 18 million through his brutality and oppressive exactions.

ʿUmar ibn ʿAbd al-ʿAzīz collected 120 million through his justice and development of the land. Ibn Hubayrah collected 100 million, in addition to provisions for the troops and wages for the laborers. Each year, Yūsuf ibn ʿUmar sent from it between 60 and 70 million, counting among this 16 million in stipends for those who had preceded him from among the people of Syria. The postal service cost 4 million; the tirāz, 2 million; and the residences of youths and maidens, 10 million.

ʿAbd al-Raḥmān ibn Jaʿfar ibn Sulaym said: “The revenue of this insignificant province reached three billion. Whatever was reduced from the ruler’s wealth increased the wealth of the subjects.”

The Sawād continued under acreage-based assessment and kharaj until al-Manṣūr, during the Abbasid period, shifted it from kharaj to crop-sharing, because prices had fallen and the produce could no longer cover the kharaj. He reassessed the Sawād, making it subject to crop-sharing.

Abū ʿUbayd advised al-Mahdī to place land subject to kharaj under crop-sharing at one-half if it was irrigated by natural water flow, at one-third if irrigated by dāliya devices, and at one-quarter if irrigated by dawālīb, with nothing else due from them besides that share. He also advised that an area-based kharaj be assessed on date palms, vineyards, and trees, determined according to their proximity to the markets. The fixed assessment was to be applied as follows: when the yield reached an amount equivalent to two kharaj payments, a full kharaj would be imposed; if it fell short, it would be waived.