Study Erodes Image of Pre-Columbian Farmers
Bower, Bruce, Science News
Traditional farming in central Mexico, first implemented around 3,500 years ago, caused at least as much soil erosion as plows, livestock raising, and other techniques introduced by the Spanish in the 16th century A.D., according to a new study,
And a return to traditional farming methods in order to make more efficient use of agricultural land, now under consideration in Mexico, probably will not produce the desired results, geographer Sarah L. O'Hara of the University of Sheffield in England and her colleagues assert in the March 4 NATURE.
"[The researchers] have provided a landmark study which shatters the myth of pre-Columbian America as an Eden in which people were 'transparent in the landscape'," writes Karl W Butzer, a geographer at the University of Texas at Austin, in a commentary accompanying the new report.
O'Hara and her co-workers obtained 21 sediment cores, ranging in length from about 4 feet to more than 8 feet, from the floor of Lake Patzcuaro, which lies more than a mile above sea level in central Mexico. Archaeological evidence for human settlements in the highlands surrounding Lake Patzcuaro dates back about 4,000 years.
Soil erosion into the lake, indicated by a predominance of clay and minerals associated with nearby agricultural land rather than natural lake sediments, first appears in core segments carbon-14 dated from around 3,600 to 2,900 years ago, the scientists say, These dates correspond to the rise of maize cultivation in central Mexico, they maintain. …