An enduring question about the Maya civilization in its heyday in the first millennium A.D. has been: How did they feed so many people?
As studies have found much higher Maya population densities than previously estimated, scholars suspected that the farmers grew more than corn, beans and squash and developed more large-scale agriculture to feed the multitude. Perhaps they mastered the cultivation of manioc, a root crop common today in the American tropics.
But archaeologists and paleobotanists, hard as they tried, failed to discover direct and compelling evidence for manioc cultivation by the pre-Columbia Maya of Central America and Mexico, or any other ancient American cultures — until now.
Archaeologists at the University of Colorado, excavating this summer at a buried Maya village in El Salvador, reported yesterday the discovery of remains of a field of cultivated manioc that grew 1,400 years ago. They said this was the earliest evidence for domestication of the carbohydrate-rich tuber in the Americas.
The manioc field was found at Cerén, an archaeological site 20 miles northwest of San Salvador that is sometimes called the Pompeii of the New World. Around the year 600, the eruption of a nearby volcano buried Cerén’s buildings, artifacts and landscape under deep ash.
“This field was a jackpot of sorts for us,” said Payson D. Sheets, an anthropology professor at Colorado. “Manioc’s extraordinary productivity may help explain how the Classic Maya at huge sites like Tikal in Guatemala and Copán in Honduras supported such dense populations.”
In previous research at Cerén, just one manioc plant, also commonly called cassava, was found in a kitchen garden. Dr. Sheets said this led everyone to think that manioc must have had a minor place in the diet.
“How wrong we were,” he said, and he was not alone. A 1996 anthology on ancient Maya agriculture made only one reference to manioc, stating that “the role of root crops in the Maya diet is unknown.”
The team led by Dr. Sheets used ground-penetrating radar, drills and test pits to uncover the neat rows of manioc plantings 10 feet deep. Hollows left by decomposed plant material were cast in dental plaster to preserve their shapes and were subsequently identified as manioc tubers. The bush grows as high as six feet, and some of its roots, or tubers, are three feet long. They are usually ground into a high-carbohydrate flour.
The Colorado researchers are working with scientists at the Smithsonian Institution to develop techniques to detect starch grains like those from manioc in the soil of village ruins. “We don’t want to find out that Cerén was unique in manioc cultivation,” Dr. Sheets said.