The spread of agriculture into northern Central Asia: Timing, pathways, and environmental feedbacks

Over the past decade, researchers have directed greater focus toward understanding Bronze (3200-800 BC) and Iron Age (800 BC-AD 400) economies of Central Asia. In this article, we synthesize paleobotanical data from across this broad region and discuss the piecemeal archaeological evidence for agriculture in relation to environmental records of vegetation and climate change. The synthesis shows that agricultural products were present in northern Central Asia by the mid-3rd millennium BC; however, solid evidence for their spread even further north into the Altai Mountains and southern Siberia only comes from the late 2nd and early 1st millennia BC. The earliest crops introduced into Central Asia likely came as a mixed package of free-threshing wheat, naked barley, and broomcorn millet, an assemblage pioneered further south along the northern foothills of the Central Asian mountains. Further east, in Mongolia, and debatably to the west of Central Asia, in the steppe of northern Kazakhstan and the southern Ural region of Russia, the earliest evidence of agriculture (with a similar mixed assemblage) is considerably later, roughly late 1st millennium BC. The lack of clear-cut early evidence for agricultural goods either east or west of the Central Asian mountain belt suggests that agriculture spread northward along these mountains, based on an agropastoral system pioneered millennia earlier at higher elevations of lower latitudes. Additionally, moister regional environmental conditions in the northern mountains after 3000 cal. BC may have increased the favorability of adopting an agricultural component in the economy.