Unlocking Ancient Maya Secrets With Modern Soil Science

Caana Caracol. Photo from Wikipedia Commons

When I see an interesting story involving soil science in the news, I like to post them here for my reading audience. One story I’ve seen in a variety of places is about a research article posted in the Soil Science Society of American Journal entitled Upland and Lowland Soil Resources of the Ancient Maya at Tikal, Guatemala (Burnett, et al., 2012). It is available as an open source research article for 30 days if you would like to read it. The Soil Science Society of American has a great summary of the research, and it’s historical significance. Here’s an excerpt:

Writing in the Nov.-Dec. issue of the Soil Science of America Journal (SSSA-J), an interdisciplinary team led by Richard Terry, a Brigham Young University soil scientist, now describes its analysis of maize agriculture in the soils of Tikal. Not surprisingly, the study uncovered evidence for major maize production in lowland areas, where erosion is less likely and agriculture was presumably more sustainable for this community of an estimated 60,000 people.

But the team also discovered evidence of erosion in upslope soils, suggesting that farming did spread to steeper, less suitable soils over time. And if Maya agriculture did cause substantial erosion, the soil loss could eventually have undercut the Maya’s ability to grow food, say the researchers.

It’s a pretty interesting story, and a mystery only solved by techniques of modern soil science. The researchers can tell what types of food was grown in the region based on the “fingerprints” left behind by the plants themselves. Broadleaf plants native to the area use the C3 photosynthetic pathway, while corn and other grasses are C4 plants.  Scientists can tell the difference between C left behind by C3 plants and C4 plants using C isotopes (C elements with different numbers of neutrons in the nucleus of the element). Using their methods, they could tell where corn was produced, and if they started growing corn on areas with steeper slopes – potentially causing erosion, and thus food shortages.

I love stories where science and history intersect, and this is a great example.

Maize. Photo from Wikipedia Commons


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