The potential of US grazing lands to sequester carbon and mitigate the greenhouse

effect

edited by RF Follett, JM Kimble and R Lal. Lewis Publishers, Boca Raton, 2001.

Hardbound, 442 pp. ISBN 1566705541. GBP60

This book covers the very timely subject of carbon sequestration in the grazing lands of

the USA. Carbon sequestration in soils was thrust into the political limelight with the

signing of the Kyoto Protocol in December 1997. This raised the possibility for the first

time that biospheric sinks of carbon could be used to offset CO2 emissions. Article 3.4 of

the Kyoto Protocol mentioned agricultural soils explicitly as a carbon sink for possible

future inclusion in carbon accounting and trading frameworks. Since then, much work in

soil science has focused on quantifying the potential of agricultural soils to sequester

carbon. This book focuses specifically on carbon in grassland soils.

It might seem odd to some readers that the USA still shows an interest in carbon

sequestration given that it revealed at the resumed COP6 meeting in Bonn in Spring 2001

that it would not ratify the Kyoto Protocol. Soon after that decision, I asked an American

colleague what impact this would have on this area of science, on US farmers and on land

managers. He replied that US farmers might still wish to sell carbon credits to nations

participating in the Kyoto process and for this reason at least, the science was still needed.

Time will tell if this type of carbon trading will be possible, but in any case, the US is

continuing to commit high levels of funding to this area with the multi-million dollar,

multi-institutional project Consortium for Agricultural Soils Mitigation of Greenhouse

Gases (CASMGS) started recently.

The book is a sister volume to the one produced by Lal et al. (1998) in which the potential

of US cropland to sequester carbon was discussed. This book differs from that one in its

format. The 1998 book summarized existing knowledge and was written entirely by its four

authors, three of whom edited the present volume. This volume, by contrast, is presented as a

series of chapters written by a different set of authors, though the editors do also contribute

to a number of chapters. As such, this book is less like a textbook and is more of a summary

of current research and the state-of-the-art findings in this field as in other books by these

editors. That is not to say that the book lacks a synthetic component. It is organized so that

the introductory chapters and those at the end of the book pull the work presented together

into a coherent whole. The final section synthesizes the work presented and quantifies the

overall potential of US grasslands to sequester carbon. Policy makers, wanting equivalent

figures to those presented in the cropland book, will not be disappointed.

Some authors have argued that the potential for carbon sequestration in grassland is not

as great as that in arable land because soil carbon levels tend to be higher under grassland

than in arable land (and therefore have less ‘‘spare capacity’’) and because organic inputs

tend not to be incorporated as effectively in grasslands as in cultivated land (Smith et al.,

2000). However, a convincing case is made in this book for the importance of grasslands.

Chapter 3 points out that vast land areas are involved and a change as small as 1% in the

soil grassland carbon stock to 10 cm is equivalent to the C-emissions from all US cropland

agriculture.

The book is divided into five sections with between two and five chapters each. The

sections cover (1) the extent, characteristics and carbon dynamics of US grazing lands, (2)

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soil and plant processes and carbon dynamics on US grazing lands, (3) managerial and

environmental impacts, (4) computer simulation and prediction, and (5) a summary and

overview. All chapters are of high quality, with authoritative authors in each subject area

contributing, and the final section pulls the various strands of information together very

well. The only real downside to this book is the lack of an index. The book is considerably

longer that the 1998 book and the lack of an index makes information more difficult to

pinpoint.

The emphasis is, of course, on US grazing land but many of the chapters (i.e. on soil

processes and computer modelling) are equally applicable to grazing lands in other

regions. In summary, the book will be of value for soil scientists, land managers and policy

makers interested in carbon sequestration as well as a wider audience. Despite the lack of

an index, anyone who has found the Lal et al. (1998) book useful (as I have) will also find

this book useful. This is another well-written and useful book from this group of editors.

References

Lal, R., Kimble, J.M., Follet, R.F., Cole, C.V., 1998. The Potential of U.S. Cropland to Sequester Carbon and

Mitigate the Greenhouse Effect. Ann Arbor Press, Chelsea, MI, 128 pp.

Smith, P., Powlson, D.S., Smith, J.U., Falloon, P., Coleman, K., 2000. Meeting Europe’s climate change commit-

ments: quantitative estimates of the potential for carbon mitigation by agriculture. Global Change Biology 6,

525–539.

Pete Smith

Department of Plant and Soil Science, University of Aberdeen,

Cruikshank Building, Aberdeen AB24 3UU, UK

E-mail address: pete.smith@abdn.ac.uk

PII: S0016 -7061 (01 )00144 -6

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