 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 he believed had not previously grown these plants.He listed eighteen such crops.Watson suggested 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.