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Ancient Maya Resource Management

Posted On January 21, 2022 | 13:47 pm | by kathys | Permalink
David Lentz revises our understanding of ancient Maya land, water, and forest management

David Lentz, professor of biological sciences at the University of Cincinnati, was a fellow in Pre-Columbian Studies in fall 2021. His research report, “Agriculture, Ethnobotany, and Agroforestry of the Ancient Maya,” described ancient Maya agricultural techniques used to cultivate a variety of crops, particularly at the ancient city of Tikal.

Q&A with David Lentz

What were some of the land and water management practices of the ancient Maya?

The ancient Maya occupied an area of wet and dry tropics, where for part of the year it is quite dry with very little precipitation, and for the rest of the year it rains in buckets every day. Also, the area is a former seabed, so the under-bedding is very porous calcium carbonate—any unabsorbed precipitation goes directly to the water table and becomes inaccessible. So, the Maya had to devise ways to capture and store water for the dry season.

At Tikal, they developed a system whereby paved plazas drained into canals that led to reservoirs, or aguadas, lined with plaster. Most of these were used for drinking water, so they were kept quite clean. My colleague, Vernon Scarborough, noticed one of the reservoirs at Tikal, known as Perdido Reservoir, had a large number of artifacts on the floor. Evidently, this reservoir was not used to store drinking water but rather for irrigation purposes. Below the reservoir was a flat field that they flooded periodically with water from the reservoir to grow crops like maize.

Another technique involved the bajos, which were essentially wetlands that dried out during the dry season. They have clay bases that hold water even during the dry season, so the Maya could continue to use the area for agriculture. Here they cultivated maize as well as root crops like Canna indica (arrowroot). Arrowroot can be planted when the soil is wet, and will continue to grow even if the earth dries out. So, as the water receded in the bajo during the dry season, the Maya could just follow the waterline and continue planting arrowroot until the water completely receded.

We also strongly suspect they were using sinkholes or rejolladas, which resembled unlined reservoirs. This allowed them to cultivate especially finicky crops like cacao, which need to be moist all the time. Elsewhere in Mesoamerica, we have evidence of ridge and furrow farming used to cultivate calorie-rich manioc at the Ceren site (in modern-day El Salvador) and vibrant home gardens which included fruit trees, beans, and squash.

How have technologies like DNA soil sediment analysis contributed to your study?

By examining samples from the reservoirs at Tikal, we developed a technique to extract DNA from the soil sediment that now entirely fills what used to be the lake. You can drill out a sample displaying all the stratigraphy and look back through time.

We determined the Maya were cultivating maize at Tikal because the photosynthetic pathway of maize has a different isotopic signature from the rest of the plants at the site. We also learned from the DNA that the Maya had repeated problems with highly toxic blue-green algae—at least four episodes of algal blooms. This would not only have been a huge health problem for the occupants but also probably a political one that reflected poorly on the city’s ruling elite. When the water next to where the king lived turned green and killed people who drank it, this may well have been interpreted as some kind of divine intervention that would have been detrimental to the ruler’s authority.

What do your findings tell us about ancient Maya agriculture more broadly?

We’ve learned a lot about Maya agriculture in the last ten years, and my project has focused on writing a book that reexamines our understanding of Maya agriculture in light of these new insights. The library has facsimiles of the four ancient Maya codices that I’m consulting for the project. In addition, [Visiting Scholar] Bill Fash, whom I first met many years ago at Copan, has been very generous with his knowledge of the ancient Maya, as well as [Director of Pre-Columbian Studies] Frauke Sachse, [Pre-Columbian Studies Fellow] Juan Carlos Melendez, and [Associate Curator, Pre-Columbian Collection] Juan Antonio Murro.

Previously, it was thought that the Maya used swidden or slash-and-burn agriculture, where they would clear part of a forest, plant crops for a few years, then move on to another area and begin again. This works if you have enough land and don’t return to a previous location for twenty years, but Maya cities were too large—they could not possibly have used this agricultural approach across Mesoamerica. These findings show us that the ancient Maya were not just slashing and burning but actively managing their resources: they would leave mature forests as long-term sources of fuel, timber, medicinal plants, and other products. Just as Maya approaches to architecture and astronomy became more complex by the Late Classic period, so did their agricultural practices.

May Wang is postgraduate writing and reporting fellow. Photo by Emily Orr, humanities fellow.