Contact Period Rural Overpopulation in the Basin of Mexico: Carrying-Capacity Models Tested with Documentary Data

Abstract

The carrying-capacity model applied to the Basin of Mexico by Sanders et al. is tested by Contact period hieroglyphic data on population and landholding from the rural tlaxilacalli (ward) of Santa María Asunción. Two calculations are made of the theoretically maximum tlaxilacalli population, one using the Sanders et al. parameters, and the second based on Asunción data. The analysis confirms the accuracy of Sanders et al.'s maize yields and average per-capita maize-consumption rate (if a variable of seed set aside is included), but suggests revision downward of household size. Although for the wrong reasons, the Sanders model correctly predicts the range of population for Asuncion. The balance between simulated household maize consumption and production shows that carrying capacity under viable, long-term strategies had been exceeded for poor and average agricultural years in the Contact period. At the tlaxilacalli level, grain deficits of greater than — 50 percent are projected for poor years, a — 28 percent deficit to + 11 percent surplus in average years, and surpluses of 10 to 74 percent in good years. In average years, to meet the maize requirements of the recorded population, continuous cultivation rather than 1:1 fallowing must have occurred on marginal land. Rural overpopulation apparent in Asunción may have been typical of many piedmont communities. The impetus for Late Horizon expansion of agricultural settlement might have come as much from rural overpopulation as from state-directed settlement to provide subsistence for Tenochtitlan.