Geoarchaeological Change in North China

Pre-Yangshao Agriculture and Landscape Change in North China

A review of “Geoarchaeological Investigation of Pre-Yangshao Agriculture, Ecological Diversity and Landscape Change in North China” by Yijie Zhuang.

This work is an important contribution to the study of the late Paleolithic and Early Neolithic periods in North China. Focusing on the “Pre-Yangshao” period (8000-7000 cal. BP) in the middle and lower Yellow River valley, Yijie Zhuang employs geoarchaeological methods to explore the changing environments of early Neolithic sites. Because the people of this period were not sedentary and left very few material remains, they have been difficult to study using the artefact-centered analysis of traditional Chinese archaeology. However, improved dating methods, the spread of new methods of analysis in environmental archaeology, and an increased attention to site-formation processes and taphonomy are rapidly improving our understanding of the period. This dissertation focuses on soil micromorphology, but its chief value lies in its integration of soil research with all other types of data on the environment of the period. It is particularly noteworthy for the way it clearly explains various types of data and highlights techniques and topics that have yet to be studied in any depth but promise to bring important insights.

The brief introduction (Chapter 1) discusses the importance of geoarchaeology for understanding the origins of farming and the establishment of agricultural societies in North China. The author emphasizes how little we know about the transition from the Paleolithic to the Neolithic in China, and—with reference to similar scholarship in the Near East—he explains how geoarchaeology can clarify this process.

The second chapter’s excellent review of environmental change from the late Pleistocene to the mid-Holocene in North China is, to my knowledge, the best overview of the subject yet written in English. As Zhuang is a geoarchaeologist, it is unsurprising that the sections on climate, geomorphology, and soils are even stronger than those on fossil pollen and zooarchaeology. His acceptance of the old argument that the presence of animals like elephants, macaques, and rhinoceros in North China indicates a subtropical habitat somewhat contradicts the pollen and paleoclimate evidence that he cites, which suggests relatively minor changes in climate in North China over the past 8,000 years (Xi’an’s mid-Holocene climate was similar to the modern climate of southern Henan). It was in fact the spread of agricultural societies that eliminated these species and their habitats.

Chapter 3 reviews the archaeological evidence. The first half of the chapter examines the terminal Paleolithic archaeology of North China, while the second half covers the early Neolithic. Most of the chapter is composed of descriptions of the most important sites and cultures across the region. The Paleolithic half concludes with a discussion of using pottery and lithics to understand subsistence. An article, entitled “Neolithisation in North China: Geoarchaeological and landscape perspectives” has been accepted by Environmental Archaeology: The Journal of Human Palaeoecology and will appear very shortly. This article summarizes important points raised in the dissertation.

Chapters 4 and 5 explain the method of analysis employed in the dissertation. Chapter 4 consists of a review of geoarchaeology and soil-based approaches to palaeoenvironmental studies in North China, focusing on the evidence for agriculture. Its major sections focus on loess, soil micromorphology, and the geo-physical and chemical analysis of soils. The chapter is very clearly written, laying out the broader issues in soil studies and the methods employed in the dissertation. Chapter 5 explains the choice of fieldwork sites and the problems with using optically stimulated luminescence (OSL) dating. Zhuang’s core methods are the “layered approach for environmental archaeology,” which essentially means analyzing soil development at various scales and considering multiple kinds of processes that affect it, and the “pedo-sedimentary approach,” which consists of analyzing the micromorphology of soil profiles taken from well-understood contexts in order to reconstruct the changing environment over time.

The following two chapters (6 and 7) lay out the actual fieldwork and soil analysis done at the two sites of Guobei, Shaanxi (Chapter 6), and Yuezhuang, Shandong (Chapter 7). Each begins with an overview of the soil and climate history of the study region. Only a specialist in soil micromorphology (which I am not) could evaluate his analysis of soil specimens, but Zhuang is very careful to explain his specific arguments, and is clearly not over-interpreting the evidence. He also uses loss-on-ignition to measure carbohydrate, total organic content, CO2 and CaCO3, and also does grain-size analysis on the sediments. The study of soil micromorphology, the central method employed, entails filling soil samples with clear glue, cutting them into slices and examining them under a microscope.

For the Guobei site, the author shows that there is strong evidence of tillage in some samples, as well as features caused by water saturation (unlikely irrigation; perhaps periodic saturation under a modified land surface) and the presence of charcoal and organic materials to the soil (GBP 3:1, 3:2, 6:4). Unfortunately these samples are not reliably dated, due to difficulties inherent in OSL dating rather than any fault of the author. In general, Zhuang’s conclusions verify accepted ideas of the region’s prehistoric environmental and agricultural history, which is itself a significant finding. His conclusion that the soil profile reflects grassland rather than forest is an important one because it shows that despite the poor preservation of pollen in loess, the region’s pollen records (which suggest an open landscape rather than forest) are generally reliable. The chapter concludes with an overview of the relationship between groundwater and vegetation distribution in the region and then explains how early Neolithic societies would have exploited such a landscape.

Unlike Shaanxi, whose loess soils are important records of Quaternary climate change, Shandong’s soils have received relatively little attention. Chapter 7 is among the most detailed studies of the early Holocene environment of Shandong. Using soil micromorphology, particle size distribution, and loss-on-ignition, it studies the effects of changing rivers and climate on the soils of the floodplain environment. The discovery of pottery shards and burnt bone at the site, as well as the carbonized remains of (not necessarily domesticated) rice and millet, make clear that the Yuezhang site was occupied by humans in the periods between river floods. However, soil analysis found no unambiguous evidence of farmed soils. A revised version of this chapter has been published in Quaternary International vol. 315 (2013).

Chapter 8 reviews the key issues in early agriculture. It discusses early Neolithic farming, including tools, weeds, length of fallow (swidden vs. permanent fields), manuring, and the specific characteristics of loess. The subsequent section concerns the impacts of agriculture, fire use and livestock on soils, which is followed by a review of evidence for human-induced erosion on slopes. The fieldwork of this dissertation is unfortunately unable to answer any of the key questions of farming methods. This is a main difficulty of soil research: only after having collected and analyzed samples does a researcher know if they contain useful information. It is for this reason, and the fact that each sample only represents one location, that we need much more of this kind of research.

Chapter 9 is a study of evidence for agriculture in the early Holocene. Zhuang discusses the assemblage of weed macrofossils found at sites across North China, which are evidence of human impact on vegetation and may well represent weeds associated with early farming. He correctly notes that they could also be the products of burning or activities associated with the managed gathering of wild plants, a precursor to actual food production. He considers whether, given the general lack of forests, North China’s Neolithic farmers had any need to practice swidden agriculture, or were more likely to be somewhat sedentary and practice short-term fallows. He nonetheless notes that the lack of solid early Neolithic houses suggests a high degree of mobility.

Although earth scientists have been doing related work for decades, the study of geoarchaeology is just beginning in China, and this is one of very few studies fully integrating the archaeology and palaeoenvironment research of the period. It is particularly welcome because it does not simply discuss the effects of the changing environment and climate on humans, but also pays attention to the human impact on the environment. To understand how agricultural societies have transformed the environment of East Asia we must begin with the earliest farmers. This kind of detailed multidisciplinary study is precisely what we need to understand the origins of farming in China.

Sources
Archaeological and geological data from published reports, laboratory analysis of samples taken from sites in North China.

Dissertation information
Division of Archaeology, Cambridge University. 2012. 470 pp. Primary Advisor: Charles French.

Brian Lander
Department of East Asian Languages and Cultures
Columbia University
bgl2114@columbia.edu

Image: Local environment, Holocene stratigraphy and examined sections at Guobei; photo by dissertation author.

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