Stone Age Chinese people began cultivating rice more than 7,700 years ago by burning trees in coastal marshes and building dams to hold back seawater, converting the marshes to rice paddies that would support growth of the high-yield cereal grain, researchers reported.
     New analysis of sediments from the site of Kuahuqiao at the mouth of the Yangtze River near Hangzhou provides the earliest evidence in China of such large-scale environmental manipulation, experts said. "It shows people were changing the environment, actively manipulating the system, and well on their way to having an agricultural way of life," said University of Toronto anthropologist Gary Crawford, who wasn't involved in the study.
     Using data from the site, it is possible to extrapolate a timeline back to the first attempts at domesticating rice, which would have occurred about 10,000 years ago, said archaeologist Li Liu of La Trobe University in Victoria, Australia, who was also not involved. That is contemporary with the development of agriculture in the Middle East.
     The finding, being published in the journal Nature, also sheds new light on an ongoing controversy in archaeology: How long did it take for crops to become fully domesticated? The evidence from China, and new finds from elsewhere, indicate that the process took much longer than researchers previously thought, said archaeobotanist Dolores Piperno of the Smithsonian Tropical Research Institute in Panama. Nonetheless, she said, there is now "little doubt that by 7,700 years ago, these people were dedicated rice farmers. ... I think people were getting all the benefits of agriculture before plants were fully domesticated."

Sources: Los Angeles Times, Austin Statesman (27 September 2007)