SCIENCE CHINA Earth Sciences • REVIEW • December 2017 Vol.60 No.12:2141–2159 https://doi.org/10.1007/s11430-017-9145-2 New methods and progress in research on the origins and evolution of prehistoric agriculture in China LU HouYuan1,2,3* 1 Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; 2 Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing 100101, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China Received September 10, 2017; accepted November 15, 2017; published online November 22, 2017 Abstract China is one of the main global centers of origin of agriculture. Foxtail millet (Setaria italica), common millet (Panicum miliaceum), and rice (Oryza sativa) were the first crops to be domesticated in China. There remain many uncertainties and controversies in our current understanding of the chronology, locations, and plant types at the origins and the process of evolution of prehistoric millet and rice farming, and their relationships with climate change and human adaptation. This review summarizes the research progress made by Chinese scientists over the last decade on the origins and evolution of prehistoric agriculture. It highlights novel techniques and methods for identifying early crop remains, including plant macrofossils (carbonized seeds, spikelets), microfossils (phytoliths, calciphytoliths, starch, pollen), and biomarkers; new evidence on the origins, development, and spread of early agriculture; and research related to climate and environmental changes. Further, we pinpoint and discuss existing challenges and potential opportunities for further in-depth investigation of the origins and evolution of agriculture and the adaption of human activities to climate change. Keywords Origins of agriculture, Dry-farming crops (millets), Rice, Phytoliths, Starch, Microfossils, Biomarkers Citation: Lu H Y. 2017. New methods and progress in research on the origins and evolution of prehistoric agriculture in China. Science China Earth Sciences, 60: 2141–2159, https://doi.org/10.1007/s11430-017-9145-2 1. Introduction evolution. For more than 10000 years, climate change and agricultural development accelerated the evolution of human Increasing evidence points to the fact that in the last deglacia- societies, which gave rise to diverse eastern and western civ- tion (ca. 19000–11000 a BP), during a sharp rise in global ilizations (Bellwood, 2005). In China, two main agricultural average temperatures (approximately 7–9°C) (Clark et al., systems emerged, namely rice farming in the south and millet 2009; Lu et al., 2007; Wang, 2011), humans transitioned from farming in the north, which nurtured a long history of farm- hunter-gatherers to primitive agricultural societies in three ing culture (Yan, 1982), its far-reaching impact persisting un- central areas in the world: China, West Asia, and Central til the present day. America (Crawford, 2006; Yan, 1982). This period marked Why did primitive agriculture emerge simultaneously in the beginning of a new era, where humans controled and cre- several mid-to-low-latitude areas around the world during the ated their food resources. The origin of agriculture is a key last deglaciation-Holocene climate warming? Dozens of the- event in the historical development of human societies, and ories have been proposed to explain the processes and mech- the prospering of agriculture forged a new path for human anisms underlying crop domestication by humans. These in- clude the evolutionary theory, oasis theory, population pres- * Corresponding author (email: [email protected]) sure theory, and social revolution theory (Bellwood, 2005; © Science China Press and Springer-Verlag GmbH Germany 2017 earth.scichina.com link.springer.com 2142 Lu H Y Sci China Earth Sci December (2017) Vol. 60 No. 12 Crawford, 2006; Zhang, 1987). These theories, regardless of have been rapidly enhanced, enriched, and disseminated. whether they involve active or passive crop domestication by For example, Professor Pearsall of the Paleoethnobotany humans, are all subjected to limitations in research materi- Laboratory, University of Missouri, USA, has established als, methods, and disciplines. Hence, many hypotheses and a phytolith database (http://phytolith.missouri.edu); Pro- speculations exist in our understanding of the last deglacia- fessor Dorian Fuller of the University College London has tion-Holocene climate warming process, and the mechanisms established an archaeobotanical database (http://www.home- of human adaption and agricultural origins (Bar-Yosef, 1998; pages.ucl.ac.uk/~tcrndfu/phytoliths.html); and Dr. Linda Crawford, 2006). Specifically, it remains unclear what are the Perry has set up a website on the international code for starch differences and similarities in the origins and patterns of rice nomenclature (http://www.fossilfarm.org/ICSN/Code.html). farming and millet farming in China, what were the effects These efforts have promoted more in-depth research in of climate and environmental changes, and what were their agricultural archeology. effects on the development of prehistoric civilizations. Researchers in China have applied multiple indicators and The key issues currently influencing in-depth investigation measures in agricultural archeology and have thus achieved of the origins and evolution of prehistoric agriculture lie in a a number of critical results, especially in crop analysis and few areas, namely, research materials, methods, and mech- identification (Lu et al., 2005; Yang et al., 2012b; Zhang et anisms. With regard to research materials, the earlier the al., 2011, 2012; Fan et al., 2011; Gu, 2009; Jin et al., 2007; crop, the scarcer and more susceptible to decomposition and Liu and Kong, 2004; Qin, 2012; Zhang et al., 2004; Zhao, podzolization its macrofossils will be, making it difficult or 2014; Zheng et al., 2007). In recent years, numerous studies impossible to find such materials (Harvey and Fuller, 2005; supported by the Chinese Academy of Sciences Strategic Pri- Pearsall, 2015; Piperno, 2006). For a long time, plant macro- ority Program, the Ministry of Science and Technology 973 fossil evidence (e.g., carbonized seeds) of crops and wild Program, the National Natural Science Foundation, and the relatives older than 8000 a BP was rarely discovered in the National Social Science Foundation, have focused on prehis- southern rice-farming and northern millet-farming regions of toric agriculture, climate change, and human adpatation in China. Thus, it was difficult to gain a comprehensive and China. These studies have conducted research from differ- accurate understanding of early agricultural origins/develop- ent perspectives, in different areas and time periods, and es- mental processes. In terms of research methods, owing to the pecially, using different methodologies (Ge et al., 2016; Gu lack of accurate identification markers for plant fossils, the et al., 2013; Jin et al., 2014; Lu et al., 2009a, 2009b; Wu questions on agricultural origins, evolution, and spread have et al., 2014; Yang et al., 2012b; Zhang et al., 2012; Hou mostly been deconstructed into debates over whether the ma- et al., 2016; Li, 2013; Qiu et al., 2016; Yang et al., 2016; terials are wild, gathered, cultivated, or domesticated, of dif- Zhang D J et al., 2016; Zhang S Q et al., 2016). Some of ferent stages and types, and whether there were multiple cen- these achievements are focused on: (1) using scientific meth- ters or a single center of origin (Deng et al., 2015; Fuller et ods to discover, differentiate, and identify early wild/domes- al., 2009; Liu et al., 2007). With regard to multidisciplinary ticated crops; (2) clarifying the process of early spatiotem- research, there is a particular lack of integrated research un- poral changes in agriculture; (3) establishing chronologically der precise chronological control on the paleoclimatic, pa- accurate relationships between climate change and agricul- leoenvironmental, and geomorphological evolutionary back- tural origins, human activities, and other aspects. This article grounds of archeological sites. Thus, from a spatiotemporal will focus on recent progress in these fields achieved by Chi- perspective, it is difficult to understand the origin and spread nese scientists by using new methods. of agriculture, and the human adaptation process and mecha- nism within the context of climatic/environmental changes. 2. New methods for crop analysis and identifi- In recent years, the international academic community cation has emphasized the innovation of analytic and identifica- tion methods for crop remains in archeological sites and Along with scientific and technological advances, the iden- sedimentary strata (Ball et al., 2016; Miller et al., 2016; tification of crop “fossils” has gradually developed from Pearsall, 2015; Piperno, 2006). In particular, progress has determining grain morphology of macrofossils (e.g., car- been made in the use of microfossils (phytoliths, starch, bonized seed grains) to determining cellular morphology pollen) (Ball et al., 2016; Pearsall, 2015; Woodbridge et of macrofossils, morphology of microfossils (phytoliths, al., 2014) and biomarkers (proteins, isotopes, molecular starch), and molecular and genetic biomarkers (Pearsall, compounds, DNA) (Dallongeville et al., 2015; Izawa et al., 2015; Piperno, 2006). These research methods have one 2009) for the differentiation of crops