The intensification of pre-industrial cereal agriculture in the tropics: Boserup, cultivation lengthening, and the Classic Maya

Abstract

Through a review of recent research in tropical ecology, soils science, and agronomy, this paper develops a model of tropical agricultural intensification through cultivation lengthening that applies to non-industrial cereal production in moist-to-wet tropical lowlands under conditions of high population density. Contrary to the predictions of many archaeological models, in tropical agricultural societies lacking plows, draft animals, or chemical fertilizers, or in which irrigation or intensive wetland agriculture are not practiced, progressive reduction and eventual elimination of the fallow period is not the only ecologically feasible means of intensifying agricultural production. More productive and sustainable under certain circumstances is intensification through cultivation lengthening, wherein farmers increase per hectare crop outputs through intensive weeding and mulching. To demonstrate the model’s analytical utility I apply it to the case of population growth and agricultural intensification in the Classic-period southern Maya lowlands of Mesoamerica. I propose that prior to the ninth-century Maya “collapse,” some but not all high-density southern lowland populations included cultivation lengthening in their repertoire of intensification strategies. Adoption of the practice helps explain how high-density populations sustained themselves agriculturally for decades after surpassing the productive limitations of alternative intensification strategies. My model of cultivation lengthening is an elaboration of a largely overlooked proposal made several decades ago by Ester Boserup.