In the latest Norwegian Archaeological Review Hafsaas-Tsakos argues for seeing archaeological Kerma, what the Middle Kingdom Egyptians referred to as Kush, as shifting from a 'periphery' to a 'centre' in the world system at that time. (This article is not a particularly botanical one, but Nubia is always close to my heart, so how can I pass up a note on it.... for a botanical side to this note, read on). This argument is one that needs to be made, again (it has been made before by Stuart Tyson Smith). Kerma was probably the largest city in the Nile valley at its heyday (1700-1560 BC), and one of the great world cities at that time (particularly as the cities of the Indus and the Oxus had pretty much withered away by this date). The importance of Kerma a few centuries earlier is indicated by the large scale, and heavily fortified Egyptian military presence at the Second Cataract, indicated by the many Egyptian fortresses and their garrisons of the Middle Kingdom (this article includes a nice photo of one of the last, unsubmerged fortresses of Nubia at Shelfak). It seems odd that the author of this paper opines that the Egyptian presence was just about trade and did not involve control of Lower Nubia, as military towns and inscription attest to garrisons patrolling swathes of Lower Nubia (see, e.g. Joe Wegner's article in JARCE 32 (1995) 127-160)-- presumably to keep the natives in line and assure supply lines to and from Egypt. As is so often the case, economic administration and military control went hand-in-hand.
Unfortunately, this article says little about what commodities flowed from Kerma northward to make it such a centre, or what flowed from Kerma's periphery to Kerma. The importance of gold sources in the Third Cataract to Second Cataract stretch of the Nile and the Red Sea hills to the east are well-known, but I would like to flag some plant resources, of course. In her list of possible commodities, the authors notes incense. The importance of incense should be underscored. Incense was central to Egyptian temple ritual, its smoke literally helped to feed (and communicate with) the gods; and it was a required in the embalming of royal mummies. One of the forms of incense of 'ntyw, was likely frankincense or myrhh or a collective term for both. Egyptian sources indicate that this often came from the mysterious land of Punt but also flowed from Nubia. But the sources of true Frankincense (Boswellia) and myrrh (Commiphora) lie far away in Yemen, southern Oman and Somalia. Nubia was one of the point of contact then with poorly understand trades links to much further away. This centrality of incense goes back to the very beginnings of Egyptian written record, and probably before, even to the Predynastic period (see, e.g. some discussion in the recent book by David Wengrow). More than half a century ago, Henri Frankfort (The Birth of Civilization in the Ancient Near East) drew attention to the importance of incense to both early Egypt and Mesopotamia and he even speculated that traders from the two societies might have met and exchanged ideas of kingship and culture in the incense ports of Yemen-- rather a fantasy, but the importance of distantly imported incense is clear.
Hafsaas-Tsakos illustrates an imported Near Eastern juglet that probably contained fragrant olive oil or the like from a grave at Kerma period Ukma. The excavations at Ukma, published in the 1980s, provide the other tantalizing clue to Kerma's links to cultures to the east: finds of broomcorn millet (Panicum miliaceum), identified by the archaeobotanist Van Zeist (his short report in English on 'The Plant Remains' can be found in the french monograph by Vila). The importance of this lies in the fact that this species is absent from Egypt, the Levant and Mesopotamia at this time. This crop appeared in the Indus valley in the Late Harappan period, after 2000 BC (as part of a larger group of Chinese imports, see pg. 36 in my J. World Prehistory paper of 2006). There are possibly earlier finds of the mid-late Third Millennium BC reported from Yemen and eastern Iran (Tepe Yahya). Other Third Millennium find comes from further north in Central Asia. It is well-known that some African crops moved east, via sea, to India by, or just after 2000 BC; Panicum miliaceum is the one crop for which we have evidence that it moved the other way, in the world of Kerma/ Kush.
Hafsaas-Tsakos is right to put Kerma on the map of a Bronze Age world system, but such an expansion of the map needs to also include areas upstream that linked the upper Nile to Eritrea, Northern Ethiopia and the Red Sea, with its ties to the incense lands of Yemen and Dhofar. The millet from Kerma-age Ukma is the forensic clue that there were contacts, even if via down the line trade, between Kerma and these cultures to the East and South, in Yemen and to the Indo-Iranian region beyond (and from there ultimately to China where this Panicum crop originated (on its origins, see previous posts on Dadiwan and Cishan). Kerma was another centre but part of its importance lies in its links to these poorly-studied, maritime 'peripheries,' which in their own right were central to the flow of key-valued resources (like incense) with which new cultigens piggy-backed.
For more on the history & archaeology of Nubia, try this site from the expert Dr. David Edwards.
For a googlemap of many sites in Nubia, including Kerma (which you can see if you zoom in), try here.