Foreword Global agriculture is now at the crossroads. The Green Revolution of the last century that gave many developing countries such as India a breathing spell, enabling them to adjust the growth of their human populations better to the supporting capacity of their ecosystems, is now in a state of fatigue. Average growth rates in food production as well as factor productivity in terms of yield per unit of mineral fertilizer (NPK) are both declining. Yet, India and other developing nations are still confronted with the need to produce more food and other farm commodities under conditions of diminishing arable land and irrigation water resources per capita and with expanding biotic and abiotic stresses, some linked to global climate changes. In January, 1968, several months before Dr. William Gaud coined the term “Green Revolution,” I made the following statement in a presidential address to the Agricultural Sciences Section of the Indian Science Congress held in Varanasi: Exploitative agriculture offers great dangers if carried out with only an immediate profit or production motive. The emerging exploitative farming community in India should become aware of this. Intensive cultivation of land without con- servation of soil fertility and soil structure would lead, ultimately, to the springing up of deserts. Irrigation without arrangements for drainage would result in soils getting alkaline or saline. Indiscriminate use of pesticides, fungicides, and herbicides could cause adverse changes in biological balance as well as lead to an increase in the incidence of cancer and other diseases, through the toxic residues present in the grains or other edible parts. Unscientific tapping of underground water will lead to the rapid exhaustion of this wonderful capital resource left to us through ages of natural farming. The rapid replacement of numerous locally adapted varieties with one or two high-yielding strains in large contiguous areas would result in the spread of serious diseases capable of wiping out entire crops, as happened prior to the Irish potato famine of 1854 and the Bengal rice famine in 1942. Therefore, the initiation of exploitative agriculture without a proper understanding of the various consequences of every one of the changes intro- duced into traditional agriculture, and without first building up a proper scientific and training base to sustain it, may only lead us, in the long run, into an era of agricultural disaster rather than one of agricultural prosperity. Since enhancement in productivity per unit of land is the only pathway available to most population-rich, but land-hungry, countries like India, for the purpose of meeting the food needs of a fast-growing population, I started working on what I termed “an ever-green revolution movement.” Ever-green revolution involves the enhancement of farm produc- tivity in perpetuity without associated ecological or social harm. In his 2002 book, The Future of Life, E.O. Wilson endorsed this concept: The problem before us is how to feed billions of new mouths over the next several decades and save the rest of life at the same time, without being trapped in a iii q 2006 by Taylor & Francis Group, LLC Faustian bargain that threatens freedom and security. No one knows the exact solution to this dilemma. The benefit must come from an ever-green revolution. The aim of this new thrust is to lift food production well above the level obtained by the Green Revolution of the 1960s, using technology and regulatory policies more advanced and even safer than those now in existence. For an ever-green revolution, we need, first and foremost, to have sustainable soil systems. In spite of all the advances in aquaculture, the soil will remain the main source of food. It is in this context that Biological Approaches to Sustainable Soil Systems is an extremely timely and valuable contribution to a wider understanding of what needs to be done for the sake of a truly modern agriculture and for the sake of future generations. We owe a deep debt of gratitude to Dr. Norman Uphoff and all the editors and contributors for their labor of love to the cause of enhancing the productivity and profitability for a wide range of farming systems on an environmentally sustainable basis by sharing both scientific knowledge and practical experience. There is a growing conflict between the proponents of organic farming and chemical farming. Chapters in this book bring out clearly that there is no need to abandon all external inputs and that there can be synergy between organic and inorganic inputs. The book provides the scientific basis for low external-input agriculture. Soil health is treated in a holistic manner involving attention to the physics, chemistry, and microbiology of soil systems. The various chapters could help scientists chart out and embark on a program of “soil breeding” for high productivity. Such initiatives for sustainable agriculture should receive as much attention as crop breeding has been given if we are to promote advances in productivity in perpetuity without adverse ecological consequences. Water is becoming a very serious constraint in many countries and of growing concern. This is where Norman Uphoff has rendered a very valuable service by promoting the System of Rice Intensification (SRI) method adapted from agronomic practices developed in Madagascar (Chapter 28). Experience in India has shown that this methodology leads to nearly 40% saving in water without affecting the yield of the crop, indeed, as a rule, increasing crop yields with reduced external inputs. As decisions on land use are invariably water-use decisions, land and water use will in the future have to be dealt with in a more integrated manner. I hope that this ambitious and timely book will be read and used widely in order to ensure the long-term viability and sufficiency of food production systems around the world. M.S. Swaminathan Forewordiv q 2006 by Taylor & Francis Group, LLC Contents PART I: Overview 1. Understanding the Functioning and Management of Soil Systems 3 Norman Uphoff, Andrew S. Ball, Erick C.M. Fernandes, Hans Herren, Olivier Husson, Cheryl Palm, Jules Pretty, Nteranya Sanginga and Janice E. Thies 2. Soil System Management in the Humid and Subhumid Tropics 15 Ana Primavesi 3. Soil System Management in Temperate Regions 27 G. Philip Robertson and A. Stuart Grandy 4. Soil System Management under Arid and Semi-Arid Conditions 41 Richard J. Thomas, Hanadi El-Dessougi and Ashraf Tubeileh PART II: Soil Agents and Processes 5. The Soil Habitat and Soil Ecology 59 Janice E. Thies and Julie M. Grossman 6. Energy Inputs in Soil Systems 79 Andrew S. Ball 7. The Rhizosphere: Contributions of the Soil–Root Interface to Sustainable Soil Systems 91 Volker Ro ¨ mheld and Gu ¨ nter Neumann 8. The Natural Rhizobium –Cereal Crop Association as an Example of Plant–Bacteria Interaction 109 Frank B. Dazzo and Youssef G. Yanni 9. The Roles of Arbuscular Mycorrihizas in Plant and Soil Health 129 Mitiku Habte 10. Moving Up within the Food Web: Protozoa and Nematodes 149 Gregor W. Yeates and Tony Pattison 11. Soil Fauna Impacts on Soil Physical Properties 163 Elise ´ e Oue ´ draogo, Abdoulaye Mando and Lijbert Brussaard v q 2006 by Taylor & Francis Group, LLC 12. Biological Nitrogen Fixation in Agroecosystems and in Plant Roots 177 Robert M. Boddey, Bruno J.R. Alves, Veronica M. Reis and Segundo Urquiaga 13. Enhancing Phosphorus Availability in Low-Fertility Soils 191 Benjamin L. Turner, Emmanuel Frossard and Astrid Oberson 14. Phytohormones: Microbial Production and Applications 207 Azeem Khalid, Muhammad Arshad and Zahir Ahmad Zahir 15. Crop Genetic Responses to Management: Evidence of Root–Shoot Communication 221 Autar K. Mattoo and Aref Abdul-Baki 16. Allelopathy and Its Influence in Soil Systems 231 Suzette R. Bezuidenhout and Mark Laing 17. Animals as Part of Soil Systems 241 Alice N. Pell PART III: Strategies and Methods 18. Integrated Soil Fertility Management in Africa: From Knowledge to Implementation 257 Bernard Vanlauwe, Joshua J. Ramisch and Nteranya Sanginga 19. Managing Soil Fertility and Nutrient Cycles through Fertilizer Trees in Southern Africa 273 Paramu L. Mafongoya, Elias Kuntashula and Gudeta Sileshi 20. Biological Soil Fertility Management for Tree-Crop Agroforestry 291 Go ¨ tz Schroth and Ulrike Krauss 21. Restoring Productivity to Degraded Pasture Lands in the Amazon through Agroforestry Practices 305 Erick C.M. Fernandes, Elisa Wandelli, Rogerio Perin and Silas Garcia 22. Direct-Seeded Tropical Soil Systems with Permanent Soil Cover: Learning from Brazilian Experience 323 Lucien Se ´ guy, Serge Bouzinac and Olivier Husson 23. Restoration of Acid Soil Systems through Agroecological Management 343 Olivier Husson, Lucien Se ´ guy, Roger Michellon and Ste ´ phane Boulakia 24. Conservation Agriculture and Its Applications in South Asia 357 Peter Hobbs, Raj Gupta and Craig Meisner 25. Managing Soil Fertility on Small Family Farms in African Drylands 373 Michael Mortimore Contentsvi q 2006 by Taylor & Francis Group, LLC 26. Restoring Soil Fertility in Semi-Arid West Africa: Assessment of an Indigenous Technology 391 Abdoulaye Mando, Dougbedji Fatondji, Robert Zougmore ´ , Lijbert Brussaard, Charles L. Bielders and Christopher Martius 27. Leguminous Biological Nitrogen Fixation in Sustainable Tropical Agroecosystems 401 Robert M. Boddey, Bruno J.R. Alves and Segundo Urquiaga 28. Soil Biological Contributions to the System of Rice Intensification 409 Robert Randriamiharisoa, Joeli Barison and Norman Uphoff 29. Contributions of Managed Fallows to Soil Fertility Recovery 425 Erika Styger and Erick C.M. Fernandes 30. Green Manure/Cover Crops for Recuperating Soils and Maintaining Soil Fertility in the Tropics 439 Roland Bunch 31. Compost and Vermicompost as Amendments Promoting Soil Health 453 Allison L.H. Jack and Janice E. Thies 32. Practical Applications of Bacterial Biofertilizers and Biostimulators 467 Rafael Martinez Viera and Bernardo Dibut Alvarez 33. Inoculation and Management of Mycorrhizal Fungi within Tropical Agroecosystems 479 Ramon Rivera and Felix Fernandez 34. Trichoderma: An Ally in the Quest for Soil System Sustainability 491 Brendon Neumann and Mark Laing 35. Evaluation of Crop Production Systems Based on Locally Available Biological Inputs 501 O.P. Rupela, C.L.L. Gowda, S.P. Wani and Hameeda Bee 36. Bio-Char Soil Management on Highly Weathered Soils in the Humid Tropics 517 Johannes Lehmann and Marco Rondon 37. Improving Phosphorus Fertility in Tropical Soils through Biological Interventions 531 Astrid Oberson, Else K. Bu ¨ nemann, Dennis K. Friesen, Idupulapati M. Rao, Paul C. Smithson, Benjamin L. Turner and Emmanuel Frossard 38. Profile Modification as a Means of Soil Improvement: Promoting Root Health through Deep Tillage 547 Nico Labuschagne and Deon Joubert 39. Rhizosphere Management as Part of Intercropping and Rice–Wheat Rotation Systems 559 Liu Xuejun, Li Long and Zhang Fusuo Contents vii q 2006 by Taylor & Francis Group, LLC 40. Managing Polycropping to Enhance Soil System Productivity: A Case Study from Africa 575 Zeyaur Khan, Ahmed Hassanali and John Pickett PART IV: Related Issues 41. Effects of Soil and Plant Management on Crop Pests and Diseases 589 Alain Ratnadass, Roger Michellon, Richard Randriamanantsoa and Lucien Se ´ guy 42. Revegetating Inert Soils with the Use of Microbes 603 Gail Papli and Mark Laing 43. Impacts of Climate on Soil Systems and of Soil Systems on Climate 617 Rattan Lal 44. Economic and Policy Contexts for the Biological Management of Soil Fertility 637 Sara J. Scherr 45. Village-Level Production and Use of Biocontrol Agents and Biofertilizers 647 B. Selvamukilan, R. Rengalakshmi, P. Tamizoli and Sudha Nair 46. Measuring and Assessing Soil Biological Properties 655 Janice E. Thies 47. Approaches to Monitoring Soil Systems 671 David Wolfe 48. Modeling Possibilities for the Assessment of Soil Systems 683 Andrew S. Ball and Diego De la Rosa 49. Opportunities for Overcoming Productivity Constraints with Biologically-Based Approaches 693 Norman Uphoff 50. Issues for More Sustainable Soil System Management 715 Norman Uphoff, Andrew S. Ball, Erick C.M. Fernandes, Hans Herren, Olivier Husson, Cheryl Palm, Jules Pretty, Nteranya Sanginga and Janice E. Thies Introductionviii q 2006 by Taylor & Francis Group, LLC Introduction This book has been constructed by the editors and contributors as a report on the state of knowledge and practice for a more biologically oriented and informed agriculture appropriate to a wide range of contemporary agroecosystems. It advances numerous explanations and conclusions for sustainable soil-system management even though we know this is a rapidly expanding area for research and field-based innovation, with many answers still to be found. The editors and contributors, representing many institutions and diverse disciplines, have worked in dozens of countries. What has brought them together is their involve- ment with research and/or experience which shows that agricultural production can be increased at the same time that it is made more sustainable by being less dependent on the exogenous resources that have driven the expansion of agriculture in the past century. The book focuses on and illuminates ways in which endogenous processes within soil systems offer opportunities to expand agricultural output with less reliance on external inputs, even while these continue to play an important role in contemporary agriculture. The book is neither antichemical in orientation nor opposed in principle to the use of external inputs. These will remain important in the decades ahead, and, in fact, the book presents much evidence supporting the optimizing use of mineral fertilizers with biological interventions. However, their pre-eminent role will surely change. For many economic, environmental, and equity reasons, it would be unwise not to consider alter- native or complementary approaches to conventional “modern” agriculture. No one can say with certainty what will be the future prices and availability of fossil fuel-based energy and agrochemical inputs. However, it is unlikely that their costs will not increase in real terms in the years ahead. Fortunately, many opportunities have been emerging in recent years to move agri- culture in more biologically driven directions that are less dependent on such inputs. This book shows that there are many ways in which a variety of crops can be produced more abundantly and more cheaply by managing and intensifying endogenous processes in soil systems. Improvements in the growing environments for crops can capitalize on existing genetic potential to achieve substantial increases in output, often 50–100% and sometimes more, with less reliance on external inputs, as summarized in Chapter 49. Many innovations in agricultural systems have been empirical, not driven by scientific knowledge, but rather by efforts to solve specific problems of soil-system constraints or decline. However, it is desirable that technology does not run too much ahead of science. Improvements in soil-system performance should be explicable in terms of scientific knowledge that can make these innovations more generalizable, more transparent, more replicable, and more optimal and sustainable. Knowing better their limitations and finding additional opportunities can lead to their wider and safer use. This book thus seeks to foster a closer connection between science and practice where now there is often some estrangement. The 104 contributors come from 28 countries, presently based in Africa (24), the United States (24), Latin America (18), Asia (18), Western Europe (12), and 4 each in the ix q 2006 by Taylor & Francis Group, LLC Middle East and Oceania. Denominating contributors’ disciplines is difficult since both original training and current work are important, but these often diverge. Because the contributors represent so many different disciplines and have divergent roles along the research-development continuum, the voices and concerns of the chapters that follow present considerable variety. The different tones and perspectives that readers will find in these chapters mirror the diversity of the underground world about which the authors are seeking to communicate. The variation we trust will make for more inter- esting reading. We have included both practitioners and researchers in this review since advancing knowledge in this domain is not a simple linear process of going from science to practice. Practice has often given impetus to scientific inquiry and insights. We look forward to having richer foundations for these various strands of theory and practice in the decades ahead as productive knowledge and experience accumulate. However, we can already identify, assemble, and share enough knowledge so that agriculture in this new century appears positioned for a more successful and sustainable future. There is no need for dire or gloomy predictions. Both authors and readers of a book that is intended for a multidisciplinary audience face a similar challenge — to optimize between breadth and depth. The editors invited persons with recognized expertise in many different subject areas to contribute from their knowledge. Our request was to focus on the most important things for nonspecialists to know on the respective subjects without compromising substance and scientific rigor. The editorial team, which collectively has broad and deep expertise on soil systems around the world, took responsibility for writing one-third of the book, the remainder being by experts from around the world. The managing editor, himself a social scientist by original training, undertook to ensure coherence in the full set of presentations and to have them presented in language that is broadly accessible. As seen from the table of contents, this book represents an effort to chart some new directions for agricultural science and practice. It is not, however, “breaking new ground” in that what is presented in Parts I and II has roots in the scientific literature that go back often half a century (e.g., phytohormones) or more (e.g., the effects of mycorrhizal associations). Much new knowledge is offered through the syntheses and applications presented in Part III, with amplifications in Part IV. Contemporary work shows significant benefits from mobilizing well-documented biological processes within soil systems. Agricultural plants have coevolved with other flora and fauna for several hundred million years. This has led to many productive symbiotic relationships that are severed when crops are treated as separate from and independent of the ecosystems in which they function. The original idea for this book was suggested by Russell Dekker, senior editor of Marcel Dekker, in a discussion in June 2003 with Norman Uphoff, who became managing editor for this project. Both saw value in bringing together what is known from many countries and disciplines about this “biocentric” way of thinking about agricultural science and practice that is gaining ground. Special thanks go to Virginia Montopoli at the Cornell International Institute for Food, Agriculture and Development (CIIFAD) for her support in producing this book. An undertaking as ambitious and complex as this required continuous and skilled administrative assistance to bring it to fruition. The concept of an alternative paradigm for crop and soil sciences that is more biologically oriented came into the literature over a decade ago when one member of the editorial team, Pedro Sanchez, presented it in a paper at the 15th World Congress of Soil Science in Mexico (Sanchez, 1994). Since this direction was first articulated, accumulating knowledge and practice have given shape and momentum to this paradigm. Introductionx q 2006 by Taylor & Francis Group, LLC There is still much more to be known and done. However, we expect that readers will agree, after assessing the scientific foundations of this emerging paradigm and its empirical accomplishments to date, that agriculture in the 21st century can be made both more productive and sustainable by accepting this more holistic orientation and associated knowledge than by simply projecting the current paradigm into the future without considering biological factors and actors in more active and central roles. Reference Sanchez, P.A., Tropical soil fertility research: towards the second paradigm. In: Transactions of the 15th World Congress of Soil Science, Acapulco, Mexico. Mexican Soil Science Society, Chapingo, Mexico, 65–88 (1994). Introduction xi q 2006 by Taylor & Francis Group, LLC PART I: OVERVIEW q 2006 by Taylor & Francis Group, LLC [...]... 18 2 .1. 1 .1 Nutrient Availability 18 2 .1. 1.2 Nutrient Replenishment 18 2 .1. 1.3 Organic Matter 18 2 .1. 2 Biodiversity as a Pervasive Fact of Life in the Tropics 19 2.2 Nutrient Dynamics and Soil Management in Tropical Ecosystems 19 2.2 .1 Interactions between Physical and Biological Factors 20 2.2.2 Physical and Chemical Interactions 21 2.2.3 Root... and stored in the soil and used in situ (Savenije, 19 98) This is different from “blue water,” which is captured in artificial or natural storage facilities or pumped from underground stores and then conveyed to some point of use Finding ways to induce plants to develop better q 2006 by Taylor & Francis Group, LLC Biological Approaches to Sustainable Soil Systems 12 plant root systems and building up soil. .. above- and 15 q 2006 by Taylor & Francis Group, LLC 16 Biological Approaches to Sustainable Soil Systems TABLE 2 .1 Broad Contrasts of Temperate and Tropical Soil System Characteristics Tropical Oxisol/Utisol Temperature regime Predominant clay form Cation exchange capacities (CEC) Soil pH Rooting depth Key compounds Biological properties affecting agriculture Temperate Mollisol Warm to hot Variable-charge... actual and potential contributions of soils to the productivity of intensively managed systems, particularly in temperate regions which rely heavily on exogenous inputs, are undervalued Figure 3 .1 illustrates how soils are dynamic, living systems that are integral parts of larger ecosystems Soil subsystems participate fully in the processes that are common to ecosystems as a whole — energy flow; the.. .1 Understanding the Functioning and Management of Soil Systems Norman Uphoff, Andrew S Ball, Erick C.M Fernandes, Hans Herren, Olivier Husson, Cheryl Palm, Jules Pretty, Nteranya Sanginga and Janice E Thies CONTENTS 1. 1 Components of Soil Systems 3 1. 2 Understanding Soil System Dynamics 5 1. 2 .1 Difficulties in Analyzing Biological Components 6 1. 2.2 Methodological... smallest category has effects on soil system performance that are far out of proportion to its measurable share 3 q 2006 by Taylor & Francis Group, LLC Biological Approaches to Sustainable Soil Systems 4 † Mineral elements are usually about half of the soil s volume, even though they can appear to be its totality The mineral portion of soil, which differs from system to system in its chemical composition... soil systems are basically the same across different climatic, edaphic, and other conditions, but they will sound somewhat different when played by the different soil- system “orchestras” that differ according to various combinations of biophysical and other factors Well-functioning soil systems have the following requirements according to Ana Primavesi, another contributor to this volume: † A well-aggregated... with soil biota of many kinds, sometimes even incorporating the management of weeds into cropping systems to take advantage of what such plants can contribute, such as q 2006 by Taylor & Francis Group, LLC Biological Approaches to Sustainable Soil Systems 10 Shadow effects and allelopathy No tillage Permanent living or dead vegetal cover on soil Protection from impact of raindrops Reduction of run-off... intraradices in root-free soil, Appl Environ Microbiol., 65, 14 28– 14 34 (19 99) Ladha, J.K et al., Opportunities for increased nitrogen-use efficiency from improved lowland rice germplasm, Field Crops Res., 56, 41 71 (19 98) Margulis, L and Sagan, D., Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors, University of California Press, Berkeley (19 97) Pretty, J., Agri-Culture: Reconnecting... – 511 (20 01) Wolfe, D., Tales from the Underground: A Natural History of the Subterranean World, Perseus, Cambridge, MA (20 01) q 2006 by Taylor & Francis Group, LLC 2 Soil System Management in the Humid and Subhumid Tropics Ana Primavesi University of Santa Maria, Rio del Sul, Brazil CONTENTS 2 .1 Soil System Dynamics and Biodiversity in the Humid Tropics 17 2 .1. 1 Three Puzzles of Tropical Soils . Root–Shoot Communication 2 21 Autar K. Mattoo and Aref Abdul-Baki 16 . Allelopathy and Its Influence in Soil Systems 2 31 Suzette R. Bezuidenhout and Mark Laing 17 . Animals as Part of Soil Systems 2 41 Alice N. Pell PART. Thies CONTENTS 1. 1 Components of Soil Systems 3 1. 2 Understanding Soil System Dynamics 5 1. 2 .1 Difficulties in Analyzing Biological Components 6 1. 2.2 Methodological Issues and Opportunities 6 1. 3 Soil Systems. Measuring and Assessing Soil Biological Properties 655 Janice E. Thies 47. Approaches to Monitoring Soil Systems 6 71 David Wolfe 48. Modeling Possibilities for the Assessment of Soil Systems 683 Andrew