The Arab Agricultural Revolution is a conjectured transformation in agriculture from the 8th to the 13th century in the Islamic region of the Old World. The name[a] was coined by the historian Andrew Watson in an influential 1974 paper. He listed eighteen crops that were widely diffused during the Islamic period, including four staple crops, namely durum wheat, Asiatic rice, sorghum, and cotton. He also argued that techniques such as irrigation were spread across the region at that time. The paper was not based on direct archaeological or scientific evidence, and its approach has been called old-fashioned and philological.
Some scholars have disagreed with parts of Watson's proposal, arguing that the four staple crops were already widely disseminated before that period, and that Islamic irrigation built on rather than replacing the Roman irrigation network in Spain. Against this, the historian Paolo Squatriti, reviewing Watson's paper 40 years on, noted that it had proven useful to many different historical agendas, and had held up surprisingly well in the face of new findings in archaeology and archaeobotany.
In 1974, the historian Andrew Watson published a paper, "The Arab Agricultural Revolution and Its Diffusion, 700-1100". The paper proposed an extension of Spanish historian Antonia Garcia Maceira's 1876 hypothesis of an agricultural revolution in Al-Andalus (Islamic Spain). In Paolo Squatriti's view, it also recalled the Belgian economic historian Henri Pirenne's 1939 view of the way that a seventh century Islamic maritime power in the Mediterranean had prevented Europe from trading there.
Watson argued that the economy established by Arab and other Muslim traders across the Old World enabled the diffusion of many crops and farming techniques across the Islamic world, as well as the adaptation of crops and techniques from and to regions outside it. Crops from Africa, such as sorghum, from China, such as citrus fruits, and from India, such as mango, rice, cotton and sugar cane, were distributed throughout Islamic lands, which, in his opinion, had not previously grown these plants. He listed eighteen such crops.[b] He further argued that these introductions, along with an increased mechanization of agriculture and irrigation, led to major changes in economy, population distribution, vegetation cover, agricultural production and income, population, urban growth, distribution of the labour force, industries linked to agriculture, cooking, diet and clothing in the Islamic world.
Watson's work was met with some early scepticism, including from historians such as Jeremy Johns in 1984. Johns noted that Watson's selection of 18 plants in his book Agricultural Innovation in the Early Islamic World was "peculiar", since the banana, coconut, mango and shaddock were unimportant in the Islamic region at the time, detracting from the discussion of the staple crops. Johns further noted that the evidence of diffusion of crops was imperfect, that Watson made "too many minor slips and larger errors" such as getting dates wrong or claiming that a 1439 document was Norman, and had failed to make best use of the evidence that was available, such as of the decline of classical agriculture, or even to mention the changing geomorphology. Johns however concluded that "The hypothesis of an 'Abbasid agricultural revolution is challenging and may well prove useful".
The historian Eliyahu Ashtor wrote in 1976 that agricultural production declined in the period immediately after the Arab conquest in areas of Iraq (Mesopotamia) and Egypt, on the limited basis of records of taxes collected on cultivated areas. In a 2012 paper focusing on the Saw?d area of Iraq, Michele Campopiano concluded that Iraqi agricultural output declined in the 7th to 10th century; he attributed this decline to "competition of the different ruling groups to gain access to land surplus".
However, by 2008 the archaeozoologist Simon Davis, advancing archaeological evidence that sheep in Portugal increased in size during the Islamic period, could take it for granted that in the Iberian peninsula
Agriculture flourished: the Moslems introduced new irrigation techniques and new plants like sugar cane, rice, cotton, spinach, pomegranates and citrus trees, to name just a few... Seville had become a Mecca for agronomists, and its hinterland, or Aljarafe, their laboratory.
The historian of Islam Salah Zaimeche noted in 2002 that the "accepted wisdom" that agriculture was not improved until the last few centuries in Europe had been overturned by work by Watson, Thomas Glick and L. Bolens among others. For example, Glick noted that the sakia,[c] or animal-powered irrigation wheel, was likely introduced to Islamic Spain in early Umayyad times (in the 7th century), that improvements to it were described by Hispano-Arabic agronomists in the 11th and 12th centuries; and that from there, sakia irrigation was spread further around Spain and Morocco.
Zaimeche further observed that Islamic agricultural practice was documented by the mediaeval agronomists Muhammad bin Ibr?h?m Ibn Bass?l (11th century) of Toledo in his book D?w?n al-fil?ha (The Court of Agriculture), and Ibn al-'Awwam al-Ishb?l? of Seville in his book Kit?b al-Fil?ha (Treatise on Agriculture). Ibn Bass?l had travelled widely across the Islamic world, returning with a detailed knowledge of agronomy. His practical and systematic book describes over 180 plants and how to propagate and care for them, including leaf and root vegetables, herbs, spices and trees. Ab? l-Khayr described in minute detail how olive trees should be grown, grafted, treated for disease, and harvested, and gave similar detail for crops such as cotton.
In 2009, the historian Michael Decker[d] stated that widespread cultivation and consumption of four staples, namely durum wheat, Asiatic rice, sorghum and cotton were already commonplace under the Roman Empire and Sassanid Empire, centuries before the Islamic period. He suggested that their actual role in Islamic agriculture had been exaggerated, arguing that the agricultural practices of Muslim cultivators did not fundamentally differ from those of pre-Islamic times, but evolved from the hydraulic know-how and 'basket' of agricultural plants inherited from their Roman and Persian predecessors. In the case of cotton, which the Romans grew mainly in Egypt, the plant remained a minor crop in the classical Islamic period: the major fibre was flax, as in Roman times. Decker further asserted that the advanced state of ancient irrigation practices "rebuts sizeable parts of the Watson thesis," since for example in Spain, archaeological work indicated that the Islamic irrigation system was developed from the existing Roman network, rather than replacing it. Decker agreed that "Muslims made an important contribution to world farming through the westward diffusion of some crops", but that the introduction of "agronomic techniques and materials" had been less widespread and less consistent than Watson had suggested. Furthermore, there is clear evidence that agricultural devices such as watermills and waterwheels, shadufs, norias, sakias, water screws and water pumps were widely known and applied in Greco-Roman agriculture long before the Muslim conquests.
Looking back over 40 years of scholarship since Watson's theory, the historian and linguist Paolo Squatriti[e] noted in 2014 that the thesis had been widely used and cited by historians and archaeologists working in different fields. It "proved to be applicable in scholarly debates about technological diffusion in pre-industrial societies, the 'decline' of Islamic civilization, the relations between elite and peasant cultural systems, Europe's historical Sonderweg in the second millennium CE, the origins of globalization, [and] the nature of Mediterraneity." Squatriti noted that Watson had originally trained in economics, and applied this interest to his historical studies. Squatriti described Watson's paper as concise and elegant, and popular for its usefulness in supporting the theses of many different historians. He observed that Watson's thesis did not depend on claims of new introductions of plants into any region, but of their "diffusion and normalization", i.e. of their becoming widely and generally used, even if they were known from Roman times. Calling Watson's "philological" approach "old fashioned", and given that Watson had worked "virtually without archaeology", Squatrini expressed surprise that recent research in archaeobotany has failed to "decisively undermine" Watson's thesis.
The most plausible hypothesis points to an Almoravid construction from 1136-1137. The structure was later reused in the Almohad period to supply the lower part of the Alcazaba with water. The watermill was operational up until the end of the fifteenth century, when, according to tradition, Queen Isabella the Catholic ordered it to be taken down because the noise it produced prevented her from sleeping.