Understanding variation in prehistoric agricultural productivity: The importance of distinguishing among potential, available, and consumptive yields

Based on a model derived from an analysis of co,temporary maize yields in T ennessee, Baden and Beekman claim that Mississippian yields would have rang ed between 8 bu/acre (501.7 kg/ha and 30 bu/acre (1,881.3 kg/ha). Using nin eteenth-century observations of Native American farmers I noted in 1999 tha t available maize yields ranged between 3.7 and 42.67 bu/acre (232.1 to 2,6 76.3 kg/ha), with a mean of 18.9 bu/acre (1,185.4 kg/ha)Sor groups that did not have plows. Consumptive yields would have been lower; probably closer to an average of 10 bu/acre (627.2 kg/ha). In this paper; I clarify the dif ferences between potential yields, available yields, and consumptive yields to illustrate the advantages of my approach. I discuss some factors that a ffect maize plants prior to harvest, leading to available yields that may b e lower than potential yields, and conditions that reduce the quantity of m aize kernels available for consumption after the harvest Baden and Beekman argue that modern agricultural technology provides a more reasonable baseli ne analog for modeling ancient maize productivity than nineteenth-century N ative American technologies. In contrast I explore agricultural yield data for Native Americans and Euroamericans from a number of tribes and stares f or 1850, 1867, and 1878. A comparison of these data shows that, overall, yi elds obtained by Native American farmers tend to be lower than yields for c ontemporaneous Euroamerican farmers. My approach using agricultural product ivity data from nineteenth-century Native Americans, coupled with a conside ration of potential, available, and consumptive yields, provides a plausibl e foundation for the evaluation of late prehistoric yields.