Adaptability of millet led to initial adoption in well-watered locales with arable soils, with the intensification of millet cultivation linked to infrastructural improvements including the alteration of waterways for irrigation.

An international team of researchers led by Dr. Alicia Ventresca-Miller, assistant professor of anthropology at the University of Michigan, used Bayesian modeling of isotope data to better understand the translocation of millet in north-central Asia. Their results upend earlier theories that tied agricultural spread to trade routes associated with mountain corridors.

“The successful cultivation of millet depended upon rainfall and arable land, thus locales with these advantages were early to adopt this domesticate,” says Ventresca-Miller, who is also assistant curator of archaeological science for the U-M Museum of Anthropological Archaeology. “The intensification of millet consumption over time depended on infrastructure, for example irrigation and the alteration of waterways.”

Ancient agricultural improvements

The shallow root structure of millet, its adaptability to various soil types, and efficient water use made it the ideal crop for building resilient economies in northern Asia. However, efforts to increase agricultural production are advantageous in places where rain-fed farming is possible or riverine flow is uninterrupted.

Investments in infrastructure, including the redirection of water and construction of irrigation canals radically altered agricultural outputs. Other improvements, such as the manuring of fields, may have served a dual purpose as livestock ingested chaff after the harvest while depositing nitrogen-rich droppings.

Transmission linked to arable land in the steppes

Bayesian modeling of dietary information, taken from the bones of ancient humans and animals from sites in modern-day Kazakhstan, Mongolia, and Russia, was used to demonstrate the transmission of millet. The research team then tied this model to underlying information on rainfall and cropland to determine the potential for millet cultivation. Early evidence of millet consumption occurred in areas where cultivation was straightforward, with enough rainfall and appropriate soils. In less advantageous locales, there were often smaller patchworks of arable land, often associated with hills or rock outcrops. Millet was translocated in a patchy manner, first tracking cropland in rain-fed locales and later in drier locales at higher elevations.

Contrary to previous models, in which the transmission of livestock and grains is argued to have occurred only along a single continuous mountain corridor or along routes of exchange associated with the proto-Silk Roads, Ventresca-Miller’s results indicate that the transmission of millet was also linked to arable land in steppe landscapes where rain-fed agriculture was possible. The spread of millet cross-cut mountain corridors into open landscapes in the western steppe and central Siberia following waterways and cropland.

More information:

Ventresca-Miller, A.R.; Wilkin, S.; Smithers, R.; Larson, K.; Spengler, R.; Haruda, A.; Kradin, N.; Bazarov, B.; Miyagashev, D.; Odbaatar, T.; et al. Adaptability of Millets and Landscapes: Ancient Cultivation in North-Central Asia. Agronomy 2023, 13, 2848.


Contact details for the media:

Alicia R. Ventresca-Miller