Reconstructing Rice Cultivation Intensity and Water Regimes through Functional Weed Ecology: Modern Case Studies from Japan and Bangladesh and Application to the Maoshan Site, China

WU Rubi1,2*, Mizanur Rahman2, Mohammod Abdur Rahim3, John Hodgson4, KIKUCHI Yukiko5, NASU Hiroo6, Michael Charles4, Amy Bogaard4, JIN Guiyun1, and CHEN Xuexiang1

The Lower Yangtze River basin (LYRB), China is widely acknowledged as one of the regions where japonica rice originated. Work over recent decades has revealed that early rice cultivation in the LYRB varied in terms of wetness levels and scale. Some sites in these early farming systems also incorporated dryland crops such as foxtail and broomcorn millets. It is necessary to study rice growing conditions on a case-by-case basis to understand the development of rice farming and domestication. Functional ecology has proved useful in western Eurasia as a means of comparing weed flora and crop growing conditions between modern traditional cultivation systems and archaeological assemblages. In the present study, functional weed ecology was applied for the first time in East and South Asia. Weed assemblages were recorded from experimental rice plots that have been traditionally managed for over 20 years in the Nishikubo wetland, Japan, and from a traditionally managed organic farm in Bangladesh. The results show that paddy rice plots can successfully be identified as intensively managed plots, contrasting with extensive low-input systems, on the basis of weed functional ecology. Also, paddy rice can be distinguished from dryland farming of cereals and pulses in Europe. A first archaeobotanical application of this method, to the rice weed assemblage from Maoshan (Late Liangzhu culture) in the LYRB supports its identification as wet paddy rice. Such findings confirm the potential of functional weed ecology for revealing the management of archaeological paddy field sites in the LYRB, China and beyond.