A wet and dry story: distinguishing rice and millet arable systems using phytoliths

Abstract

Changing rice and millet arable systems were closely linked to social and environmental changes in Neolithic and Early Bronze Age in Central China. Two methods are used here to distinguish between rainfed millet farming and rice farming, using phytoliths from crop weeds found in ash middens and mixed cultural layer contexts. Samples were taken from three sites, Xipo and Huizui, in the Yellow River Valley in Henan, and Baligang which is situated towards the south of the province. The samples are from three cultural phases, Yangshao, Longshan and Erlitou. The phytoliths used are from grass leaves, so are not identified to genera or species but rather grouped into ecological categories, and canonical correspondence analysis was applied. Next, the ratios were calculated of phytolith morphotypes from cells that are genetically predisposed to form phytoliths (fixed), compared to silica bodies from cells that will form silica bodies when there is sufficient water uptake (sensitive). The results show differentiation between millet and rice and differences in how wet the rice fields were. The region experienced social and climate change throughout this time and this is reflected in the results.