Trees, Crops and Soil Fertility. Concepts and Research Methods

451 Pages·2003·14.66 MB·English

by  G Schroth

TREES, CROPS AND SOIL FERTILITY
CONCEPTS AND RESEARCH METHODS

Trees, Crops and Soil Fertility
Concepts and Research Methods
Edited by
G. Schroth
Biological Dynamics of Forest Fragments Project
National Institute for Research in the Amazon
Manaus
Brazil
and
F.L. Sinclair
School of Agricultural and Forest Sciences
University of Wales
Bangor
UK
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Library of Congress Cataloging-in-Publication Data
Trees, crops and soil fertility: concepts and research methods
edited by G. Schroth and F. L. Sinclair.
p. cm.
Includes bibliographical references (p. ).
ISBN 0-85199-593-4 (alk. paper)
1. Soil fertility. 2. Agroforestry. 3. Soil fertility--Research. 4. Agroforestry--Research. I.
Schroth, G. (Goetz) II. Sinclair, Fergus L.
S596.7. T74 2002
631.4’22--dc21
2002006036
ISBN 0 85199 593 4
Typeset by Wyvern 21 Ltd, Bristol
Printed and bound in the UK by Cromwell Press, Trowbridge
Contents
Contributors ix
Foreword xi
M. Swift
1. Impacts of Trees on the Fertility of Agricultural Soils 1
G. Schroth and F.L. Sinclair
1.1 Trees and the Development of Agriculture 1
1.2 Objectives and Structure of the Book 9
2. Economic Aspects of Soil Fertility Management and 13
Agroforestry Practices
A.-M.N. Izac
2.1 Introduction 13
2.2 Factors Influencing Farmers’ Decisions About Soil 14
Fertility Management Practices
2.3 Hierarchy of Agricultural Systems as a Background to 18
the Understanding of Farmers’ Constraints
2.4 Anatomy of a Decision at the Farm Scale and Economic 18
Methods for Understanding such Decisions
2.5 Landscape and Global Scales: Soil Fertility and 32
Agroforestry Trees as Part of Natural Capital
3. Designing Experiments and Analysing Data 39
R. Coe, B. Huwe and G. Schroth
3.1 Synopsis 39
v
vi Contents
3.2 Experimental Objectives, Treatments and Layout 40
3.3 Fallow Experiments 48
3.4 Measurements and Sampling Designs 52
3.5 Analysing the Data 61
3.6 Spatial Structure and Its Analysis 67
4. Soil Organic Matter 77
G. Schroth, B. Vanlauwe and J. Lehmann
4.1 Synopsis 77
4.2 Methods for Total Soil Organic Carbon 86
4.3 Physical Fractionation Methods 86
4.4 Chemical Methods 88
4.5 Biological Methods 89
5. Soil Nutrient Availability and Acidity 93
G. Schroth, J. Lehmann and E. Barrios
5.1 Synopsis 93
5.2 Methods for Soil Nitrogen 104
5.3 Methods for Soil Phosphorus 112
5.4 Methods for Soil Sulphur 121
5.5 Methods for Potassium, Calcium and Magnesium in Soil 125
5.6 Methods for Soil Acidity 127
6. Decomposition and Nutrient Supply from Biomass 131
G. Schroth
6.1 Synopsis 131
6.2 Methods for Biomass and Nutrient Input with Litter 140
6.3 Methods for Decomposition and Nutrient Release from 143
Biomass
6.4 Measures of Resource Quality 148
7. Nutrient Leaching 151
J. Lehmann and G. Schroth
7.1 Synopsis 151
7.2 Methods for Soil Solution Composition 158
7.3 Tracer Methods for Nutrient Leaching 163
7.4 Dyes as Tracers for Preferential Flow Paths 165
8. Nutrient Capture 167
G. Schroth and J. Lehmann
8.1 Synopsis 167
8.2 Tracer Methods for Nutrient Uptake 174
Contents vii
9. Nutrient Exchange with the Atmosphere 181
G. Schroth and J. Burkhardt
9.1 Synopsis 181
9.2 Methods for Atmospheric Nutrient Inputs 185
9.3 Methods for Nutrient Losses from Burning 188
10. Soil Structure 191
M. Grimaldi, G. Schroth, W.G. Teixeira and B. Huwe
10.1 Synopsis 191
10.2 Methods for Soil Bulk Density 195
10.3 Methods for Aggregate Stability 196
10.4 Methods for Soil Porosity and Pore Size Distribution 198
10.5 Measuring the Role of Soil Organic Matter in Aggregate 204
Stability
10.6 Soil Micromorphology and Image Analysis 207
11. Soil Water 209
W.G. Teixeira, F.L. Sinclair, B. Huwe and G. Schroth
11.1 Synopsis 209
11.2 Methods for Soil Water Content 215
11.3 Methods for Soil Water Potential 221
11.4 Methods for Soil Hydraulic Properties 225
11.5 Estimating Topsoil and Subsoil Water Use with Stable 232
Isotopes
12. Root Systems 235
G. Schroth
12.1 Synopsis 235
12.2 Methods for Studying Root Distribution 240
12.3 Distinction of Roots of Different Species 245
12.4 Methods for Root Dynamics, Production and Turnover 246
13. Biological Nitrogen Fixation 259
K.E. Giller
13.1 Synopsis 259
13.2 Microbiological Methods for Studying Rhizobia 265
13.3 Simple Methods for Determining Whether a Legume 265
is Fixing Nitrogen
13.4 Isotope-based Methods for Measurement of Nitrogen 266
Fixation
13.5 Estimating Nitrogen Fixation in Field Settings 268
13.6 Methods Based on Nitrogen Fixation Transport 269
Products
13.7 Estimating Total Amounts of Nitrogen Fixation 270
viii Contents
14. Mycorrhizas 271
D.L. Godbold and R. Sharrock
14.1 Synopsis 271
14.2 Inoculation Methods 280
14.3 Sampling of Plant Roots for Mycorrhizal Studies 281
14.4 Quantification of Mycorrhizas 281
14.5 Identification of Mycorrhizal Fungi 283
14.6 Estimation of Mineral Nutrient Uptake Through 286
Mycorrhizas
15. Rhizosphere Processes 289
D. Jones
15.1 Synopsis 289
15.2 Obtaining a Representative Sample of Rhizosphere Soil 294
15.3 Methods for Rhizosphere Soil Chemistry 297
15.4 Methods for Rhizosphere Biological Activity 298
15.5 Quantification of Root Carbon Loss into the 300
Rhizosphere
15.6 Rhizosphere Mathematical Modelling 300
16. Soil Macrofauna 303
P. Lavelle, B. Senapati and E. Barros
16.1 Synopsis 303
16.2 Sampling of Macrofauna: the TSBF Methodology 318
16.3 Other Sampling Methods 320
16.4 Manipulative Experiments 322
17. Soil Erosion 325
M.A. McDonald, A. Lawrence and P.K. Shrestha
17.1 Synopsis 325
17.2 Quantitative Methods 336
17.3 Qualitative Methods 341
References 345
Index 423
Contributors
Edmundo Barrios, Centro Internacional de Agricultura Tropical (CIAT),
AA 6713 Cali, Colombia
Eleusa Barros, National Institute for Research in the Amazon (INPA), CP 478,
69011–970 Manaus, AM, Brazil
Jürgen Burkhardt, Institute of Agricultural Chemistry, University of Bonn,
Karlrobert-Kreiten-Str. 13, 53115 Bonn, Germany
Richard Coe, World Agroforestry Centre, International Centre for Research in
Agroforestry (ICRAF), PO Box 30677, Nairobi, Kenya
Ken E. Giller, Plant Production Systems, Department of Plant Sciences,
Wageningen University, PO Box 430, 6700 AK Wageningen, The Netherlands
Douglas L. Godbold, School of Agricultural and Forest Sciences, University of
Wales, Bangor, Gwynedd LL57 2UW, UK
Michel Grimaldi, Institut de Recherche pour le Développement (IRD), UR 137,
Centre de Recherche d’Île de France, 32 ave Henri Varagnat, 93143 Bondy Cedex,
France
Bernd Huwe, Institute of Soil Science and Soil Geography, University of Bayreuth,
95440 Bayreuth, Germany
Anne-Marie Izac, World Agroforestry Centre, International Centre for Research
in Agroforestry (ICRAF), PO Box 30677, Nairobi, Kenya
Davey Jones, School of Agricultural and Forest Sciences, University of Wales,
Bangor, Gwynedd LL57 2UW, UK
Patrick Lavelle, Laboratoire d’Ecologie des Sols Tropicaux, 32 ave Henri
Varagnat, 93143 Bondy Cedex, France
Anna Lawrence, Environmental Change Institute, University of Oxford, 5 South
Parks Road, Oxford OX1 3UB, UK
ix