Advances in Agronomy

1. Auflage 2010
ISBN: 978-0-12-381036-6
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 223 Seiten

Advances in Agronomy continues to be recognized as a leading reference and a first-rate source for the latest research in agronomy. As always, the subjects covered are varied and exemplary of the myriad of subject matter dealt with by this long-running serial.
* Maintains the highest impact factor among serial publications in agriculture
* Presents timely reviews on important agronomy issues
* Enjoys a longstanding reputation for excellence in the field

Autoren/Hrsg.

Inhaltsverzeichnis

1;Front Cover;1
2;Advances in Agronomy;4
3;Copyright Page;5
4;Contents;6
5;Contributors;8
6;Preface;10
7;Chapter 1: Phosphorus Solubilization and Potential Transfer to Surface Waters from the Soil Microbial Biomass Following Drying–Rewetting and Freezing–Thawing;12
7.1;1. Introduction;13
7.1.1;1.1. Rationale;14
7.1.2;1.2. Objective;16
7.2;2. Factors Affecting Solubilization of Phosphorus from the Soil Microbial Biomass;16
7.2.1;2.1. Primary solubilization processes;17
7.2.2;2.2. Thresholds of solubilization;19
7.2.3;2.3. Impacts on microbial communities;22
7.3;3. Factors Controlling Transfer to Surface Waters;25
7.3.1;3.1. Internal cycling of phosphorus;25
7.3.2;3.2. Solubilization, mobilization and transfer of phosphorus;26
7.4;4. Uncertainties;30
7.4.1;4.1. Measurement of soil microbial biomass phosphorus;30
7.4.2;4.2. Scales of measurement of impacts of abiotic perturbations;31
7.4.3;4.3. Spatial variability of microbial phosphorus;34
7.4.4;4.4. Relative contributions of sources of phosphorus in soil;35
7.5;5. The Significance of Changing Climate and Soil Management;36
7.6;6. Conclusions and Future Work;38
7.7;Acknowledgments;39
7.8;References;39
8;Chapter 2: Improving Productivity of Crops in Water-Limited Environments;48
8.1;1. Introduction;49
8.2;2. Water-Limited Potential Yield;50
8.2.1;2.1. Risk management: A case study;52
8.3;3. Water as a Limiting Resource: An Analytical and Diagnostic Framework;53
8.4;4. Water Balance and Transpiration;55
8.4.1;4.1. Available soil water at sowing;55
8.4.2;4.2. Evaporation from the soil and other nonproductive losses of water during the growing season;58
8.4.3;4.3. Residual soil water at maturity;63
8.5;5. Transpiration Efficiency;65
8.6;6. HI: Converting Biomass into Grain;68
8.6.1;6.1. Adapting phasic development to environment;68
8.6.2;6.2. Managing vegetative growth;69
8.6.3;6.3. Effects of water deficits, high temperatures and frost on floral fertility;69
8.6.4;6.4. Carbon balance during grain filling;70
8.7;7. Yield Improvement by Management;71
8.7.1;7.1. Strategic crop management;72
8.7.2;7.2. Tactical crop management;72
8.7.3;7.3. Spatial variability and zone management;74
8.7.4;7.4. Diagnostic guide;75
8.7.5;7.5. Effects on economy and environment;76
8.8;8. Concluding Comments;77
8.9;Acknowledgments;78
8.10;References;78
9;Chapter 3: Advances in Understanding the Molecular Structure of Soil Organic Matter: Implications for Interactions in the Environment;88
9.1;1. Introduction;89
9.1.1;1.1. Molecular structure and carbon turnover in soils;90
9.1.2;1.2. Conceptual approach and objectives;91
9.2;2. Soil Is an Aqueous System;92
9.2.1;2.1. Water as an agent of structural organization;92
9.2.2;2.2. The effect of decomposition on aqueous solubility;95
9.3;3. Evolution of SOM Concepts;96
9.3.1;3.1. Historical approaches to define humus/SOM;97
9.3.2;3.2. Alkaline extraction: The procedure that shaped our view of SOM;98
9.3.3;3.3. Humic substances: True constituents of humus/SOM, artificial preparations or artifacts?;103
9.4;4. The ``Humic Dilemma´´ as an Element of Contemporary SOM Concepts;106
9.4.1;4.1. Polymeric nature and complexity of ‘‘humic substances’’;107
9.4.2;4.2. Aromaticity of SOM;110
9.4.3;4.3. Relating the molecular structure of organic matter to carbon turnover dynamics;113
9.4.4;4.4. Model humic substances as proxies for SOM;117
9.4.5;4.5. Organic nitrogen: N-Heterocycles as indicators for humification processes;120
9.4.6;4.6. Molecular structure: Supramolecular assembly or macromolecule?;123
9.4.7;4.7. Glass transitions and the molecular structure of SOM;129
9.5;5. Reconciliation of Four Centuries of SOM Research;130
9.5.1;5.1. What is SOM, what is it not?;131
9.5.2;5.2. How do the physical models of SOM affect assumptions about mechanisms?;132
9.5.3;5.3. The bright side of alkaline extracts and humic substance preparations: Practical applications;135
9.6;6. Outlook for the Future;137
9.6.1;6.1. What are implications for future research?;138
9.6.2;6.2. What are potential environmental implications?;139
9.6.3;6.3. Are there implications for agriculture and sustainability?;140
9.6.4;6.4. How should the ‘‘New View’’ of the physical nature of SOM be presented in educational settings and educational literature?;140
9.7;References;141
10;Chapter 4: Implications of the Knowledge Paradox for Soil Science;154
10.1;1. Introduction;155
10.2;2. Mode-1 Versus Mode-2 Research;157
10.3;3. How to Define ``Niches´´ for Soil Science When Studying the Big Environmental Issues of Today;158
10.4;4. Studying the Seven Soil Functions;160
10.4.1;4.1. Introduction;160
10.4.2;4.2. Research needs for the soil functions;161
10.5;5. How to Better Interact with Stakeholders and Policy Makers;169
10.5.1;5.1. Introduction;169
10.5.2;5.2. The policy cycle;169
10.5.3;5.3. The knowledge chain;172
10.5.4;5.4. Improving communication and public relations;174
10.6;6. The Internal Issue: How to Become an Effective Community of Scientific Practice?;177
10.6.1;6.1. Introduction;177
10.6.2;6.2. Scientific quality and integrity;177
10.6.3;6.3. The need for basic research;178
10.6.4;6.4. Soil education;178
10.7;7. Conclusions;179
10.8;References;180
11;Chapter 5: Grassland Fire Management in Future Climate;184
11.1;1. Introduction;185
11.1.1;1.1. Fire in Australia;186
11.1.2;1.2. Fire management systems;187
11.1.3;1.3. Fire and climate change;188
11.2;2. Fire Behavior in Grasslands;189
11.3;3. Fire Spread Prediction in Australian Grasslands;191
11.3.1;3.1. Head fire width;192
11.3.2;3.2. Fuel condition;193
11.3.3;3.3. Degree of curing;194
11.3.4;3.4. Dead fuel moisture content;195
11.3.5;3.5. Wind speed;197
11.3.6;3.6. Fire danger and rate of spread;200
11.3.7;3.7. Predicting rate of spread;201
11.4;4. Impacts of Climate Change on Fire Spread Prediction;204
11.4.1;4.1. Climate change scenarios;205
11.4.2;4.2. Impact of changed weather on fire behavior;207
11.4.3;4.3. Discussion;210
11.5;5. Implications for Grassland Fire Management;211
11.6;6. Conclusion;214
11.7;Acknowledgments;215
11.8;References;215
12;Index;220