June 6 (UPI) -- By studying ancient grains, researchers have gained insights into how the world's oldest cities grew and evolved some 8,000 years ago.
Using stable carbon and nitrogen isotope analysis to survey ancient, charred grains, archaeologists from the University of Oxford were able to reconstruct the growing conditions of Mesopotamia, the historical region stretching across modern-day Iraq, Syria, Turkey and Kuwait.
The research team's findings -- detailed in the journal Nature Plants -- suggest as populations in the region's ancient cities grew, farmers looked to cultivate large swaths of land instead of funneling more resources, like manure, into existing plots. Farmers didn't attempt to plant denser rows, they simply expanded.
Researchers suggest the development would have put a premium on fertile acreage, and allowed powerful landholders greater socioeconomic and political advantages -- increasing inequality in the earliest urban centers. The growth of farm acreage would have also benefitted those controlling access to specialized plough animals.
"Each cereal grain found buried in an archaeological site holds within it a record of the environmental conditions under which it was grown," lead researcher Amy Bogaard, a professor of archaeology at Oxford, said in a news release. 'Studying many samples of grain from a number of ancient sites allows us to build up a picture of how farming changed with the waxing and waning of early cities, and in particular how people coped with the need to feed growing urban populations."
Researchers found that as the scale of farming operations in Mesopotamia grew, resources were stretched thin and soil health suffered. Farming acreage declined in health as nutrients went un-replenished.
"It was a solution that enabled enormous urban agglomerations to develop, but was risky when environmental or political conditions changed," Bogaard said. "Examining how prehistoric farmers coped with changing conditions could yield some useful advice for modern day governments facing similar pressures of growing populations and changing environments."