TAXESlocal economic resources seems to date from the post-conquest settle-
ment.
However, agricultural tax rates remained somewhat fluid in Iraq
even after 'Umar. In his first term as governor of Kufa (642-46), al-
Mughira ibn Shu'ba is said to have assessed Indian peas, vineyards,
rutba, and sesame at eight dirhams per jar"ib while he exempted date
palms.I8 Then, when 'All sent Yazld al-An~ari to the Sawad in 656,
the latter was instructed to assess thickly sown wheat at one-half
dirham plus one sii' of grain per jar"ib, moderately sown wheat at one
dirham per jar"ib, thinly sown wheat at two-thirds of a dirham per
jar"ib, barley at half these rates, groves of palms and other trees at ten
dirhams per jar"ib, and grapevines over three years old and bearing
fruit at ten dirhams per jar"ib. Cucumbers, seed-grain, sesame, and
cotton were all to be exempt, although 'An did assess the reed thicket
of Burs at four hundred dirhams.I9 Apart from the measure of tax
relief represented by these rates, the attempt to adjust the rate schedule
to a tripartite classification based on the productivity of grain land
seems to reflect the indigenous division of the quality of land into
good, medium, and poor in the Babylonian Talmud.^20
In order to be valid, comparison of Sasanian and Islamic land taxes
must also take into account the units of capacity and measurement
used, since changes or local variations in units of measurement could
affect the actual tax yield directly in the mi$iiha system. The jarw used
in the Sawad was sixty square cubits, and the cubit-measure (Ar.
dhirii, used by I:Iudhayfa and 'Uthman was the length of a man's
forearm and hand stretched out, called the common (later "black")
dhirii', and about fifty-four centimeters long.2I The use of this dhirii'
would produce a smaller jar"ib of about one thousand and fifty square
meters and serve to increase the real tax burden by almost one-third.
The restoration to use of the longer royal cubit of about sixty-six and
one-half centimeters therefore represents a degree of tax relief and is
associated with Ziyad, especially in later sources, who is supposed to
have used it to measure the land of the Sawad. This dhirii' Ziyiidiyya
18 Baladhuri, Futul;, p. 270.
19 Abii Yiisuf, Kharii;, p. 133; Baladhurl, FutulJ, pp. 271, 274.
20 Rodkinson, Talmud, X, "Baba Kama," 10-11. For the same division in the Jabal,
see A.K.S. Lambton, Landlord and Peasant in Persia (London, 1953), p. 40.
21 Baladhurl, FutulJ, p. 272; W. Hinz, lslamische Masse und Gewichte, Handbuch
der Orientalistik, vo!. I, bk. I (1955), pp. 55, 60-61; Mawardi, AlJkiim as-sul!iiniyya,
p. 69; Ya'qiibi, Ta'rtkh, 11,174.