Implications of soil geochemistry for understanding agricultural cultivation by the ancient Maya.

The size and extent of Classic Maya population was dependent on the ability to produce crops through sustainable agricultural activities. The Maya used diverse cultivation systems including ditched fields. This study characterizes the geochemistry of soil profiles in a Maya ditched field near Baking Pot, Belize in order to investigate the effect of climate on Maya agriculture. The carbon isotopic composition of soil organic matter reveals that prior to Maya occupation the landscape was occupied by a mixed C3 and C4 plant community. Maya agricultural activity is recognized in the soil profiles by the most positive δ13C values and a decline in soil phosphorous concentration, both of which are indicative of the cropping of maize. A return to more negative δ13C values in the upper part of the soil profiles is indicative of cessation of Maya agricultural activity and a return to higher proportions of C3 plants.