Agricultural failure?

The Southern Maya Lowlands were comprised of a system of states, fragmented politically, but fused together by a common religion, writing system and a sophisticated culture. One of the initial ideas was that the disintegration of the political structure attributed to the abandonment of this forested interior (Lowe, 1985). While this is a viable option for contributing towards a collapse, it is not a sufficient explanation for causing such a major depopulation. Lowe’s model was soon dismissed by Santley et al. (1985) who believed that the collapse involved a systematic failure that was far more complex than just a breakdown of political hierarchies. They suggest it all began with agricultural production that eventually eroded not only the land but the economic base of the society...

It has been known for a long time that the Maya reached their peak during the Late Classic, and this has been increasingly supported by accumulating evidence, especially from ceramic and pottery studies. The Lowlands were densely occupied by peasant farmers and as population increased, the habitable landscape began to ‘fill up’ at a rapid speed (a fairly common process to many ancient civilisations dependent on simple food production). Exponential population rises occurred at large Maya sites, like Tikal, where the growth was curvilinear throughout the Classic period (Santley et al., 1985). It has been estimated that the population density per square km was 713 people (Puleston, 1973). Now this may not be as high as London’s density, but it is certainly much higher than that of Guatemala, which, according to the World Bank (2011), is 132 people per square km!

The continuous growth led to the simultaneous development of agricultural production across the Lowlands, accompanied by accelerated deforestation (confirmed from palynological evidence from the Peten, Guatemala, as well as various other sites in the Yucatan and Honduras e.g. Abrams and Rue (1988)). Santley et al. (1985) proposed that in order to increase subsistence yields, the Maya used spatially diversified cropping techniques, involving intensively cultivating slope-lands. However, repeated cultivation of slopes to maintain high yields is never a good idea, as the food production system will have a lower resistance to degradation processes and the associated erosion. This seems to be an important factor in reducing the efficiency of the agricultural system, but alone it cannot explain the nature of the Maya collapse.

And this is where deforestation becomes more important. As it is, soil fertility in tropical forests is relatively low, as nutrients essential for plant growth are either stored in the forest canopy or in the thin layer of leaf litter on the forest floor. This decaying layer of litter cannot accumulate if trees are continuously removed, and so forest clearance presents not only erosional problems, but decreases nutrients in the soil and in turn, reduces plant productivity. The exposed ground also becomes more prone to breakdown of soil structure and soil compaction, further augmenting erosion - as was the case in the Late Classic period. And even though it has been proven by numerous scholars, for example Dunning and Beach (1994) amongst others, that the ancient Maya used terracing in an attempt to reduce erosion, this was not practiced in all areas. Thus, the agricultural support base that much of the population became dependent on became progressively less resilient and unsustainable as the population continued to swell... Seems like a reasonable hypothesis so far!