Table Of ContentSoil Biological Fertility
Soil Biological Fertility
A Key to Sustainable Land Use in Agriculture
Edited by
Lynette K. Abbott
School of Earth and Geographical Sciences,
Faculty of Natural and Agricultural Sciences,
The University of Western Australia, Crawley, Australia
and
Daniel V. Murphy
School of Earth and Geographical Sciences,
Faculty of Natural and Agricultural Sciences,
The University of Western Australia, Crawley, Australia
AC.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-1-4020-1756-8 (HB)
ISBN 978-1-4020-6618-4 (PB)
ISBN 978-1-4020-6619-1 (e-book)
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© 2007 Springer
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Dedication
Professor Charles Alexander (Lex) Parker
1916-2001
Professor Lex Parker inspired many throughout his distinguished
career. Lex was equally at home at the laboratory bench and in the paddock;
his academic work was preceded by a period managing the family farm. He
never lost touch with his farming background as he searched for scientific
understanding of soil microbiological processes. He was renowned for
exploring ideas that were not fashionable and was often ahead of his time.
Lex commenced his academic career at The University of Western Australia
in 1959 and was later appointed to a Personal Chair. He encouraged
undergraduate students to pursue interests in soil and plant microbiology, and
supervised a distinguished group of postgraduate students. Lex's research
included studies of symbiotic and non-symbiotic nitrogen fixation, and he
initiated the long running research on arbuscular mycorrhizas at The
University of Western Australia. His subsequent research on root pathogens
helped to highlight, then manage, the problems they caused in Western
Australia, while inspiring others to address the problem nationally. During
the later stages of his research career, Lex became passionate about soil
fauna. He had loyal support from the farming community and persisted with
his attempts to raise awareness of the importance of soil biology in
agriculture. Many people greatly benefited from Lex's kind-heartedness,
intuitiveness and enthusiasm.
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TABLE OF CONTENTS
Preface ix
1. What is Soil Biological Fertility? 1
Lynette K. Abbott and Daniel V. Murphy
2. Impact of Fauna on Chemical Transformations
in Soil 17
Graham H. R. Osler
3. Impact of Microorganisms on Chemical
Transformations in Soil 37
Daniel V. Murphy, Elizabeth A. Stockdale, Philip C.
Brooks and Keith W. T. Goulding
4. Role of Fauna in Soil Physical Processes 61
Petra C. J. van Vliet and Paul F. Hendrix
5. Contributions of Rhizosphere Interactions
to Soil Biological Fertility 81
Petra Marschner and Zdenko Rengel
6. Contributions of Rhizobia to Soil Nitrogen Fertility 99
Alison McInnes and Krystina Haq
7. Contributions of Arbuscular Mycorrhizas to Soil
Biological Fertility 129
David D. Douds Jr. and Nancy Collins Johnson
8. Relevance of Plant Root Pathogens to Soil
Biological Fertility 163
V. V. S. R. Gupta and K. Sivasithamparam
9. Relevance of Interactions amongst Soil
Microorganisms to Soil Biological Fertility 187
Wendy M. Williamson and David A. Wardle
vii
viii
10. Managing the Soil Habitat for Enhanced
Biological Fertility 203
M. Jill Clapperton, K. Yin Chan and Frank J. Larney
11. Sustainable Farming Systems and their
Impact on Soil Biological Fertility -
Some Case Studies 225
Elizabeth A. Stockdale and W. Richard Cookson
12. Sustainability of Soil Management Practices -
a Global Perspective 241
Pete Smith and David S. Powlson
Lis t of Contributors 255
Ind ex 259
PREFACE
This book reviews the influences of management practices on soil biota
and associated processes that contribute to soil biological fertility in the
context of agricultural land use. Although it is generally acknowledged that
physical, chemical and biological factors are all important to soil fertility
(Figure 1), more attention is usually given to management of the soil
chemical and physical environment than to the soil biological environment.
Clearly, changes to the chemical and physical environment in soil influence
biological processes and subsequently the contribution that they make to soil
fertility overall. Certain soil biological processes are stimulated by soil
amendments and this includes processes that have both positive and negative
effects on plant growth. However, it is possible to override the contributions
of some beneficial soil biological processes by solely focusing on chemical
inputs to modify the chemical environment. Such an approach undervalues
the potential for some key soil biological processes to contribute to plant
productivity.
Biological
Chemical Physical
Figure 1 Soil biological, physical and chemical processes are interrelated.
A number of soil biological processes are linked, while others are not.
Consideration of the mass of microorganisms in soil as a whole (microbial
biomass) is not sufficient for complete interpretation of the effects of land
management on soil biological fertility. When one group of organisms or
biological processes is altered, others may be affected positively, negatively
ix
x
or not at all. Knowledge of these complex responses can support decision-
making aimed at achieving sustainable use of agricultural land. However,
the goals are not clearly defined as the biological characteristics of a
particular soil type that is specifically managed to sustain the soil resource
might be quite different for contrasting land uses such as food production,
agroforestry or natural vegetation. Although the level of soil biological
activity depends on the soil type, it also depends on the management
practices used, particularly the management of organic matter.
Efficient use of nutrients requires a balance between those that are
added to soil and those that are released during biological degradation of
recent additions of plant/animal residues and older organic matter in soil.
Aspects of soil biological activity that contribute to suppression of disease
and efficiency of nutrient acquisition by plants are also essential for
profitable and environmentally responsible agricultural production systems.
Although management practices need to be appropriate for soil and climatic
conditions if soils are to be sustained in a suitable biologically active state,
many important questions remain unanswered before this can be achieved.
This book provides information about how agricultural land
management practices alter aspects of soil chemical and physical fertility
with consequences for soil biological processes and vice versa. Both fauna
(Chapter 2) and microorganisms (Chapter 3) contribute significantly to
chemical transformations of nutrients in soil. These contributions are not
necessarily independent as the complexity of the food web in soil creates a
dynamic interface for changes in nutrient pools. Carbon is an essential
component in these transformations whether they are carried out by
organisms that derive their carbon from organic matter, especially from
plants (living or dead), or from atmospheric CO . In concert with chemical
2
transformations of various kinds, both fauna (Chapter 4) and microorganisms
influence their physical surroundings to various degrees. These processes
are primarily dependent on predator-prey relationships and consequently on
the form, availability and chemical state of the original source of carbon.
The root environment is a significant component of soil biology and provides
carbon to a wide range of soil organisms (Chapter 5). Rhizosphere
organisms have major influences on plant nutrient availability and some,
such as rhizobia, form specific associations with legumes (Chapter 6) which
greatly influence the C:N ratio of plant material. Less specific, although
almost ubiquitous associations between agricultural plants and arbuscular
mycorrhizal fungi have the potential to increase the efficiency of use of
phosphorus in agricultural ecosystems as well as improve soil structure
(Chapter 7) but the extent to which is occurs in field soils is difficult to
determine and disputed.
xi
If agricultural management practices take account of biological
processes in soil, there is a possibility of avoiding development of some
severe plant diseases, especially those caused by root pathogens (Chapter 8).
However, the complexity of soil biological processes is such that each
process cannot be considered independently (Chapter 9). Therefore, an
holistic approach to agricultural land management (Chapter 10) requires
practices that are based on specific principles (Chapter 11) that ensure the
whole range of important biological processes is not overridden. Only then
can we develop sustainable farming systems for the future (Chapter 12). The
goal is to take this knowledge and apply the principles to the improvement
and modification of current farming practices on a localised and regional
basis.
This book highlights the pivotal role of soil biology in agricultural
ecosystems and demonstrates the responsiveness of soil biological fertility to
changes in soil physical and chemical conditions imposed by agricultural
management practices. A number of aspects of soil biology are not covered
in depth here but they are certainly important to the holistic concept of soil
biological fertility. They include the specific impacts of soil microorganisms
on physical aspects of soil, the concept and importance of soil biodiversity,
and the emerging new methodologies for investigating soil biodiversity and
function.
Finally, we are extremely grateful to Merome Purchas for her valuable
editorial assistance and general support throughout the preparation of this
book.
Lynette K. Abbott
Daniel V. Murphy
June 2003
Chapter 1
What is Soil Biological Fertility?
Lynette K. Abbott and Daniel V. Murphy
School of Earth and Geographical Sciences, Faculty of Natural and Agricultural Sciences,
The University of Western Australia, Crawley, 6009, WA, Australia.
1. INTRODUCTION
There is increasing interest in soil management practices that enhance
biological contributions to soil fertility due to greater awareness of the need
for sustainable farming systems (e.g. Lynam and Herdt 1989, Dick 1992,
Roper and Gupta 1995, Doran et al. 1996, Swift 1997, Condron et al. 2000,
Mäder et al. 2002, von Lützow et al. 2002). This has occurred due to the
requirement for better fertiliser use efficiency which is essential in: i)
developing nations where cost and availability constrain production (Swift
1997) and ii) many developed nations where public concern over
environmental pollution from agricultural sources and associated government
legislation restricts gaseous losses and nutrient leaching (e.g. N: Hatch et al.
2002, P: Leinweber et al. 2002). There has been a considerable decline in
soil organic matter levels and associated loss of soil structure in many
intensively cropped soils throughout the world. This has caused scientists
1
L.K. Abbott & D.V. Murphy (eds) Soil Biological Fertility - A Key to Sustainable Land Use in
Agriculture. 1-15.
© 2007S pringer.
