The evolution of rice Rice has long been a staple crop across large parts of Asia, and cultivation methods have evolved as the population grew and dispersed over time. Professor Dorian Fuller tells us about his work in reconstructing the evolution of rice cultivation methods, and its wider importance in terms of our understanding of the global climate The world’s most
productive crop, rice has long formed a central part of the human diet across large parts of Asia, and the methods used to cultivate it have evolved over time. The history of rice agriculture is an area of great interest to Professor Dorian Fuller, the Principal Investigator of an NERC-backed project bringing together 13 research partners from across the world. “The general aim of the project is to develop and then deploy new methods to determine how rice was cultivated. We’re looking at the ecology of rice cultivation, and how those cultivation ecologies evolved over time and then spread over different parts of Asia,” he outlines.
evidence takes two main forms. “We’re looking at archaeobotanical seed remains, and we’re also looking at phytoliths, which are micro remains,” says Professor Fuller. Using the insights gained from these data, researchers aim to reconstruct early rice cultivation systems, dating back around 4,500 years. “Evidence indicates that the first stretch of cultivation in South East Asia was dry rice, which is not a methane producing rice. Methane-producing rice cultivation methods, wet rice, evolved later,” outlines Professor Fuller. These findings hold great relevance to our understanding of population growth and dispersal patterns. As populations
Methane levels steadily grew from 3,000 BC up to the industrial period. There’s been debate as to whether that can be explained by natural climate processes Methane levels This research is central to our understanding of how our climate has evolved. Global methane levels started to increase between 4-5,000 years ago; one hypothesis put forward to explain this increase is the development of rice paddy agriculture. “If you grow rice on an upland field under high rainfall (dry rice), it basically produces no methane, whereas if you grow it in an irrigated paddy-field (wet rice), it produces lots of methane. So the ecology of cultivation makes a big difference,” stresses Professor Fuller. The project’s work will help build a stronger evidence base in this area. “The idea behind the project was to ask whether we can ground-proof that hypothesis in terms of empirical evidence,” says Professor Fuller. The primary focus of this work is reconstructing how rice was cultivated. The project is gathering archaeobotanical data from parts of South East Asia; this
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increased, production was intensified, leading to a shift from dry rice to wet rice. “Wet rice produces four times as much grain as rain-fed rice, so you can feed four times as many people,” explains Professor Fuller. The general historical trend has been away from the cultivation of lowintensity dry rice towards wet rice; Professor Fuller and his colleagues are working to identify when this shift occurred. “Our data suggests that the big increases in wet rice production happened mainly in the last 3,000 years,” he says. This will have had an impact on atmospheric methane levels. While it is understood that greenhouse gas emissions have increased enormously since the beginning of the industrial age, research suggests that methane levels were already growing. “Methane levels steadily grew from 3,000 BC up to the industrial period. There’s been debate as to whether that can be explained by natural climate processes – the difficulty is that we don’t
see anything like this in any previous inter-glacial period,” says Professor Fuller. “If you go back to ice-core records from Greenland or Antarctica, from previous inter-glacials, you don’t see an increase in methane levels.” The growth and dispersal of wet rice cultivation is one potential explanation for this increase, which Professor Fuller believes needs to be taken into account in climate models which build on historical climate data. While it might be assumed that human activity did not have a big impact on the climate before the industrial age, in fact agriculture and cultivation had already affected the greenhouse gas budget. “Predictive climate models need to take into account that there is already this extra greenhouse gas in the atmosphere. That has implications for future planning of what we do in terms of mitigating the impact of greenhouse gas emissions,” says Professor Fuller.
The Impact of Evolving of Rice Systems from China to Southeast Asia (Early Rice) Utilizing archaeobotanical evidence the project aims to model the dispersal and evolution of rice farming systems in China and south-east Asia. This information will then be utilised to produce improved models of past wetland rice agriculture and its impact on past and present climates and populations. Funded by the National Environmental Research Council (NERC) £735,752 Project: NE/K003402/1 ; May 2013 - April 2016 Professor Dorian Q Fuller T: +44 (0)20 7679 4771 E: d.fuller@ucl.ac.uk W: http://gtr.rcuk.ac.uk/ projects?ref=NE/K003402/1 W: http://www.ucl.ac.uk/ archaeology/research/directory/ evolution-rice-fuller
Dorian Q Fuller is Professor of Archaeobotany at the Institute of Archaeology, University College London. He completed his PhD in Cambridge (2000) on the origins of agriculture in Southern India.
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