Sawad was the name used in early Islamic times for southern Iraq. It means "black land" and refers to the stark contrast between the alluvial plain of Mesopotamia and the Arabian desert. Under the Umayyad and Abbasid Caliphates, it was an official political term for a province encompassing most of modern Iraq .As a generic term, it was used to denote the irrigated and cultivated areas in any district.Sources Michele Campopiano, “Land Tax Alā l-misāḥa and muqāsama: Legal Theory and Balance of Social Forces in Early Medieval Iraq (Sixth to Eighth Centuries)”, in Journal of the Economic and Social History of the Orient, 54/2, 2011, 239-269