Phytolith evidence for rice cultivation and domestication in late-Dawenkou culture in the middle reaches of the Huai River, China

Abstract

The cultivation and domestication of rice (Oryza sativa) represents a pivotal development in East Asian agriculture; its trajectory during the Neolithic period remains a subject of considerable interest. In the middle reaches of the Huai River, rice farming emerged as a key agricultural practice in the late-Dawenkou culture (ca. 4,500–4,300 BP), though research on the environmental conditions for cultivation and domestication processes is scarce. Addressing this gap, this study presents a phytolith-based analysis of the Gaixia site, a significant late-Dawenkou settlement; 136 soil samples from various archaeological contexts at the Gaixia site, including ash pits, ditches, and house foundations, were analyzed for their phytolith assemblages and contents, focusing on rice-specific morphotypes. The results revealed a dominant presence of rice phytoliths (up to 37.78 % in content and 81.88 % in ubiquity), suggesting that rice was the main crop during this period. The sensitive to fixed phytolith ratio averaged 1.86 ± 0.83, suggesting a cultivation environment with ample water and likely involving controlled water management practices in paddy fields, supporting the water conditions required for rice cultivation in a relatively warm-dry climate. Furthermore, the high frequency of rice bulliform phytoliths with ≥9 fish-scale decorations (73.91 %) and larger sized bulliform point to advanced rice domestication. Comparisons with earlier periods (e.g., Shunshanji and Shuangdun cultures) suggest progressive intensification of rice cultivation and domestication in the region. This research provides critical insights into the agricultural developments and environmental adaptations shaping the rice farming systems of the late-Dawenkou culture, broadening understanding of rice cultivation’s role in the development of East Asian Neolithic agricultural societies.