Nature and Management of Tropical Peat Soils













Table of Contents


FAO SOILS BULLETIN 59

by
J. P. Andriesse
Consultant

Soil Resources, Management and Conservation Service
FAO Land and Water Development Division

FAO - FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome, 1988

Cover photo: Initial clearing for drainage of bush vegetation on deep peat in Brazil (photo: J.P. Andriesse)

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of Its frontiers or boundaries.

M-51
ISBN 92-5-102657-2

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© FAO 1988

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Table of Contents


Foreword

Acknowledgements

1. INTRODUCTION

1.1 Objectives
1.2 The Definition of Tropical Peats

2. DISTRIBUTION OF TROPICAL PEAT

2.1 Extent
2.2 The Main Occurrences
2.3 Application of Research

3. FORMATION OF PEATS

3.1 Introduction
3.2 Environmental Factors

3.2.1 Hydro-topography
3.2.2 Source and quality of water

3.3 Stages in Development
3.4 Type of Vegetation

4. THE MAIN CHARACTERISTICS OF TROPICAL PEATS

4.1 Introduction
4.2 Physical Properties of Organic Materials

4.2.1 General
4.2.2 Moisture relationships
4.2.3 Bulk density
4.2.4 Porosity
4.2.5 Texture and loss on ignition
4.2.6 Swelling and shrinking
4.2.7 Irreversible drying
4.2.8 Physico-chemical properties

4.3 Chemical Properties of Peat Materials

4.3.1 Introduction
4.3.2 Composition
4.3.3 Acidity
4.3.4 Exchange characteristics
4.3.5 Organic carbon
4.3.6 Nitrogen
4.3.7 Phosphorus
4.3.8 Free lime (CaCO3)
4.3.9 Sulphur
4.3.10 Trace elements

4.4 Biological Activity
4.5 Characteristics of the Peatswamps

4.5.1 Geomorphology
4.5.2 Hydrology

5. CLASSIFICATION

5.1 Introduction
5.2 Historical
5.3 Classification Systems

5.3.1 Introduction
5.3.2 Topographical classification
5.3.3 Classifications based on surface vegetation
5.3.4 Classifications based on chemical properties
5.3.5 Classifications based on botanical origin
5.3.6 Classifications based on physical characteristics
5.3.7 Classifications based on genetic processes

5.4 Conclusions
5.5 Recommended Approach
5.6 Classification of Organic Soils According to Soil Taxonomy

5.6.1 Introduction
5.6.2 Fibrists
5.6.3 Hemists
5.6.4 Saprists
5.6.5 Folists
5.6.6 Further development of soil taxonomy for the Tropics

5.7 The Classification of the Physical Environment

6. AGRICULTURAL POTENTIAL

6.1 Introduction
6.2 General Suitability for Cropping
6.3 Land Capability and Crop Suitability Evaluation

6.3.1 Introduction
6.3.2 The initial survey

6.4 Conclusions and Recommendations

7. RECLAMATION PROBLEMS

7.1 Introduction
7.2 Initial Problems in Peat Reclamation

7.2.1 Initial drainage
7.2.2 Clearing
7.2.3 Burning
7.2.4 Organization

7.3 Permanent Constraints in Peat Reclamation

7.3.1 Subsidence
7.3.2 Cultivation practices

7.4 Water-table Management

8. AGRICULTURAL MANAGEMENT

8.1 Introduction
8.2 Crop Choice

8.2.1 Choice of crop under natural drainage conditions
8.2.2 Choice of crops under improved drainage with water-table at less than 40 cm depth
8.2.3 Choice of crops assuming deep drainage

8.3 Water Management at Farm Level

8.3.1 Systems of open drains
8.3.2 Subsurface drains
8.3.3 Irrigation

8.4 Tillage and Cultivation Methods
8.5 Correcting Acidity by Liming

8.5.1 Lime requirements
8.5.2 Materials used

8.6 Fertilizer Use

8.6.1 Introduction
8.6.2 Burning
8.6.3 Basic principles
8.6.4 Nitrogen requirements
8.6.5 Phosphorus requirements
8.6.6 Potassium requirements
8.6.7 Calcium and magnesium requirements
8.6.8 Micro-nutrients or trace element requirements
8.6.9 Conclusions

8.7 Crop Protection

8.7.1 Weed control
8.7.2 Pest and disease control

9. ENERGY USE OF PEAT

9.1 Introduction
9.2 Peat as an Energy Source

9.2.1 Decomposition stage
9.2.2 Carbon and hydrogen content
9.2.3 Ash content
9.2.4 Types of fuel peat
9.2.5 Fuel properties
9.2.6 Minor factors

9.3 Resource Estimation

9.3.1 Initial survey

9.4 Peat Production

9.4.1 Introduction
9.4.2 Clearing
9.4.3 Ditching
9.4.4 Clearing of stumps
9.4.5 Methods of production and layout

9.5 Peat Extraction and Land Use Planning

9.5.1 Rapid disposal
9.5.2 Slow disposal
9.5.3 Effect of peatland distribution
9.5.4 Reclamation of freshly exploited peat deposits

10. ENVIRONMENTAL ASPECTS OF RECLAMATION

10.1 Introduction
10.2 Natural Functions of Peatswamps

10.2.1 Regulating functions
10.2.2 Production function
10.2.3 Information function
10.2.4 Miscellaneous functions

10.3 Environmental Impacts of Peat Reclamation

REFERENCES AND BIBLIOGRAPHY

APPENDIX 1 - Tests of Organic Soil Materials

APPENDIX 2 - Volumetric Relations in Soil Materials

APPENDIX 3 - Soil and Other Physical Limits for Satisfactory Crop Growth on Organic Soils

APPENDIX 4 - Linking Drainage and Soil Temperature

FAO SOILS BULLETINS