Milpa, a Long-Standing Polyculture for Sustainable Agriculture

Polyculture, or intercropping, is the practice of growing two or more crops simultaneously in time and space. The milpa is a systematic polyculture involving the simultaneous cultivation of maize ( Zea mays ), beans ( Phaseolus spp.), squash ( Cucurbita spp.), and other crops. Milpa polyculture initially emerged in the Mesoamerican region (Mexico and Central America) through the concurrent processes of managing, utilizing, and domesticating its constituent crops. It subsequently spread throughout the Americas via the diffusion of maize and the convergence of its domestication with that of its companion crops and other domesticated plants in the continent. Mesoamerican farmers made an outstanding contribution by domesticating and bringing together crops with contrasting morphological and physiological traits that are ecologically, agronomically, and nutritionally complementary. Despite its importance, few quantitative evaluations of this polyculture exist. However, these evaluations indicate that its productivity and land efficiency use (Land equivalent ratio = 1.34) are comparable to those of other intercrops studied on a global scale. We emphasize the importance of transdisciplinary efforts to study this polyculture and highlight its potential applications related to ecological interactions, plant microbiomes and breeding in order to reach sustainable production goals.