Scientists have long believed agriculture, as a human invention, dates back around 12,000 years to Iraq, Iran, the Levant and portions of Turkey, an area dubbed the "Cradle of Civilization."
That area of the Middle East was the origin of a number of the world's earliest known civilizations, assumed to have been the first to engage in purposeful plant cultivation — agriculture.
Now, however, U.S. and Israeli researchers say they've discovered a number of ancient weed species at the location of a human settlement on the shores of the Sea of Galilee, dated to 23,000 years ago, that suggest some form of early experimental attempts at cultivation.
"While full-scale agriculture did not develop until much later, our study shows that trial cultivation began far earlier than previously believed, and gives us reason to rethink our ancestors' capabilities," says Marcelo Sternberg of Tel Aviv University. "Those early ancestors were more clever and more skilled than we knew."
While weeds have historically been considered a nuisance or even a threat to agricultural farming, scientists have believed they developed in tandem with cultivation, and those found at the ancient settlement of a fisher-hunter-gatherer people known as the Ohalo II people are evidence of early plant cultivation, the researchers report in the journal PLOS ONE.
They analyzed the varieties of weeds retrieved at the site for morphological evidence of domestic kinds of cereals and harvesting tools, they said, emphasizing that their very presence was evidence of early crop farming.
"Because weeds thrive in cultivated fields and disturbed soils, a significant presence of weeds in archaeobotanical assemblages retrieved from Neolithic sites and settlements of later age is widely considered an indicator of systematic cultivation," the researchers wrote in their published study.
The researchers recovered around 150,000 specimens of plants from the well-preserved site, determining that the early human inhabitants there had collected more than 140 species of plants, with 13 known weeds intermixed with edible cereal grains.
The grains included wild varieties of oats, barley and emmer, which is still popular in Italy, where it's known as farro. Emmer is believed to have been cultivated for at least 7,000 years and is sometimes known as Pharaoh's wheat because it was common in ancient Egypt, according to an article in the Grand Forks Hearld about ancient grains.
The wild grains are sometimes known as "covered" or "hulled" wheat because their grains are enclosed in a husk or hull that doesn't fall off during threshing.
They generally don't yield as well as modern wheat, nor are they as easy to handle after harvest as modern wheat, in which the grain threshes free of the hull during harvest.
A stone grinding slab at the ancient site was evidence of cereal grains being processed and ground for consumption, the researchers say, and the discovery of sickle blades suggests deliberate and systematic harvesting of cereal crops.
Taken together, all of the findings at the site strongly suggest those early humans had a rudimentary knowledge of agriculture, and, even more significantly, showed forethought and considerable agricultural planning much earlier than science has previously believed, the researchers conclude.
