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 throughout the Islamic world, as well as the adaptation of crops and techniques from and to regions outside it.
Watson berpendapat bahwa ekonomi yang didirikan oleh Arab dan pedagang Muslim lain di seluruh Dunia Lama memungkinkan difusi dari banyak tanaman dan teknik pertanian di seluruh dunia Islam, serta adaptasi tanaman dan teknik dari dan ke daerah-daerah di luar dunia Islam.