"The most dramatic thing about this land is its seasonal changes," says Dr. Clark Erickson, referring to Llanos de Mojos, the impoverished region in Bolivia where he leads his archaeological digs. "For four or five months a year, the land is flooded. Then it dries out."
The research that Erickson, associate professor of anthropology at Penn, has conducted in the region has scholarly value - but he hopes that it will have practical results as well.
During the wet season, he says, Llanos de Mojos "is almost an aquatic world, similar to the Everglades in Florida. It has green grass, swamps, and patches of green trees popping up here and there. Many roadways are closed, so people get around by canoes or airplanes. Then comes the dry season. As the land dries, the grassland turns into shades of brown and yellow."
Llanos de Mojos is a flat landscape in the lower Andes. The unvarying flatness is interrupted by small, dense jungles near the riverbanks. The indigenous people of these forests hunt and practice "slash-and-burn" agriculture for their subsistence. Cattle ranchers live in the flat savannas.
Llanos de Mojos, says Erickson, has been a poor region for centuries. Yet there was a time when it was not.
By studying aerial and satellite photographs and the results of archaeological digs, researchers like Erickson have discovered thousands of rectangular "islands" built about twenty centuries ago by the ancestors of today's Mojos Indians. The farmers grew root vegetables, a strong caffeine-based tea plant, achiote (used as a red paint), and perhaps corn on these islands, which produced enough crops to feed a large population.
According to William Denevan, who first found these pre-Columbian
earthworks, this region was sustaining at least 200,000 inhabitants five
centuries ago. Now, most of the people in the region live in cities, not
on the land.
Making use of the region's climate
For 15 centuries, the Mojos Indians cultivated these plains by using a
farming technique that exploited the region's climate. During the dry
season, they would divide the land into rectangles 10 feet wide and
ranging from 100 feet to one-quarter of a mile long. Rectangles were
laid out 10 feet apart from each other. Then the Indians would excavate
the area between the fields some three or four feet deep. The soil that
was removed was deposited on top of the rectangular fields. When the
rainy season came, the depressions would become canals and the raised
fields would be about one foot above the water level, allowing for
normal agriculture in spite of the flooding.
To maintain the best level of water, the Indians built dikes and flood gates, which allowed them to extend the growing season by conserving moisture. Next to the fields, they built larger canals for transporting goods in canoes.
The arrival of the Spanish and with them diseases previously unknown in the Americas put an end to these gardens that were spread over an area the size of Pennsylvania. The diseases killed most of the region's Indians-and their farming techniques perished with them.
Until now. Erickson and other archaeologists working in the raised fields began to wonder whether this old farming technique could be used to help develop the economy of this impoverished region.
Erickson, who teaches "Fundamentals of Archaeology," "Andean Archaeology," and "Archaeology of Complex Societies" at Penn, spends his summers in Bolivia (its dry season). He has published and delivered several papers about the region, including one earlier this spring at the meeting of the Latin American Studies Association in Atlanta.
Through projects that attempt to duplicate what the Mojos Indians used to do, he has concluded that, even by modern standards, the ancient agricultural technique is impressive. During the rainy season, the canals drain excess water, while dikes and dams store water for the dry season. Algae and aquatic plants in the canals and the organic matter deposited at the bottom can be used to fertilize the fields. In addition, the canals can be used to collect and harvest fish.
"It would be very naive to think that these technologies can be put back
into use very easily and everyone will be happy," says Erickson. "There
have been major climatic, social, and economic changes since these
systems were last used. Rehabilitating ancient technologies requires
intensive study followed by small-scale pilot experimentation."
Rewriting an "instruction manual"
Nevertheless, from simply studying the distant past, Erickson now has
accepted the challenge of rewriting a kind of lost instruction manual
for agricultural practices. In 1990, Erickson and associates from the
local Bolivian university built about a dozen small raised fields in an
acre of flooded savanna. This experimental plot eventually produced more
corn than traditional fields of comparable size in the forests. The
station also produced cassava, a starchy root crop not cultivated in the
savannas.
After the success of that small experiment, Erickson and colleagues started taking his results to local communities.
At a typical meeting, he explains, "We discuss raised fields for two hours. They are usually very interested, and they have all sorts of concerns about the labor and time involved, where the raised fields could be built, what they are going to get out of it." Since the project is experimental, he adds, "we use incentives. We spend a lot of time discussing what an experiment is, that it might fail or it might not, and in the end it is theirs to run." The arrangement is for the diggers and the data-collectors to receive a daily salary and meals. "In the end," says Erickson, "they get the harvest and we get the data."
There is not much labor available in Llanos de Mojos to build the fields. Many of the communities are small and dispersed. Erickson keeps looking for further ties with local people, organizations, universities, and development organizations to expand the use and testing of this rediscovered way of making the region productive.
From his perspective, using ancient knowledge to develop a region's economy is the most exciting part of his archaeological work. He says he is committed to work in Bolivia for a long time - "maybe," he adds, "for the rest of my life."
Erickson has written a chapter on his current research for Archaeology in the American Tropics: Current Analytical Methods and Applications, to be published later this year by Cambridge University Press.
To help fill the gaps in the archaeological record of Llanos de Mojos, Erickson uses data from the experimental plots he is helping to build on the Bolivian savanna. The participating farmers receive technical orientation, salaries, and meals - and the harvest is theirs to keep. In return, the farmers and Erickson keep track of the agricultural yields of each plot and how much labor was required to make the system work.
Erickson then makes informed guesses about the number of people that might have lived in Llanos de Mojos before the arrival of the Spanish. He is trying to determine the number of people that were needed to work the fields, how they were organized, and how self-sufficient the system was - how, in effect, the people lived. In the meantime, Erickson keeps an eye open for any pottery and other hard clues that may shed light on the culture and beliefs of the Mojos Indians.
Although the neighbors to the west of the Mojos Indians were the powerful Incas, the Mojos remained independent of them. According to Erickson, "The Mojos were a separate, parallel culture."
Another question archaeologists like Erickson would like to answer is how the Mojos Indians learned the farming technique of the raised fields. Ancient raised fields have been found in Africa, China, New Guinea, Mexico, and Belize-as well as in South Florida, Michigan, and Wisconsin. -Esaúl Sánchez