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Cover photos: |
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Top: |
Drip-irrigated pomegranate trees on gypsiferous soils with
white surface. Cattle manure mixed with surface soil around the trees. |
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Bottom left: |
Sinkholes in strongly gypsiferous soil, fallow after
drip-irrigated vegetables. The sinkholes have formed along the drip
line. |
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Bottom right: |
Lined irrigation canal to prevent collapse and seepage from
the irrigation system. |
FAO SOILS BULLETIN 62
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED
NATIONS
Rome, 1990
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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. |
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy.
© FAO 1990
This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.
1. GYPSIFEROUS SOILS IN THE WORLD
1.1 Introduction
1.2 Origin of Gypsum in Soils
1.3 Forms of Gypsum in Soils
1.4 Classification of Gypsiferous Soils1.4.1 The American classification
1.4.2 The FAO-Unesco legend
1.4.3 The French classification
1.4.4 The Russian classification
1.4.5 International Reference Base for soil classification
1.4.6 Other classifications
2. CHARACTERISTICS OF GYPSIFEROUS SOILS
2.1 Introduction
2.2 Physical Properties2.2.1 Particle-size distribution
2.2.2 Structure
2.2.3 Soil-water relationships2.3.1 Solubility relationships
2.3.2 Gypsum and calcium carbonate interaction
2.3.3 Cation exchange properties and exchangeable cations
3. FERTILITY OF GYPSIFEROUS SOILS
3.1 Introduction
3.2 Fertility and Use of Fertilizers3.2.1 Phosphorus availability and immobilization
3.2.2. Nitrogen and organic matter
3.2.3 Calcium, magnesium and potassium
3.2.4 Micronutrients availability and problems
4. EFFECT OF GYPSUM AND CALCIUM CARBONATE ON PLANTS
4.1 Introduction
4.2 Winter Crops
4.3 Summer Crops
4.4 Classification of Field Crops Based on Their Tolerance to Gypsum
4.5 Fruit and Forest Trees
5. IMPROVEMENT OF PRODUCTIVITY OF GYPSIFEROUS SOILS
5.1 Introduction
5.2 Rainfed Agriculture
5.3 Irrigated Agriculture5.3.1 Leaching gypsum from soils
5.3.2 Irrigability of gypsiferous soils
5.3.3 Salinity and leaching requirements
6. LABORATORY METHODS FOR ANALYSING GYPSIFEROUS SOILS
6.1 Introduction
6.2 Gypsum Content of Soils6.2.1 Gypsum determination
6.2.2 The BaSO4 method (Richards 1954)
6.2.3 The amended BaSO4 method
6.2.4 Gypsum determination (Sayegh et al. 1978)
6.2.5 Gypsum determination (Lagerwerff et al. 1965)
6.2.6 Semiquantative gypsum determination by X-ray diffraction
6.2.7 Quantitative determination of gypsum content by X-ray diffraction (Friedel 1978)
6.2.8 Gypsum determination by extraction with boiling water (Kovalenko 1972)
6.2.9 Gypsum determination from loss of crystal-water content (Nelson et al. 1978)6.3 The Particle-Size Distribution of Gypsiferous Soils
6.3.1 Gypsum removal by ammonium oxalate (Coutinet 1965)
6.3.2 Gypsum removal by hydrochloric acid (Loveday 1974)
6.3.3 Pretreatment of soil with BaCl2 to coat gypsum with BaSO4 (Hesse 1974)
6.3.4 Pretreatment of soil with BaCl2 solution followed by ethanol (Matar and Douleimy 1978)
6.3.5 Pretreatment with BaCl2 solution (amended method, Vieillefon 1979)6.4 Cation Exchange Capacity and Exchangeable Cations
6.4.1 Sodium oxalate method (Sayegh et al. 1978)
6.4.2 Saturation of soil with Ba ions
6.4.3 Cation exchange capacity of calcareous and gypsiferous soils
6.4.4 Determination of exchangeable cations and CEC
APPENDIX 1 - Classification of Gypsiferous Soils According to Boyadgiev
APPENDIX 2 - Representative Profiles of Gypsiferous Soils
APPENDIX 3 - Physico-chemical Characterization of Soils in Iraq (after Barzanji 1973)
APPENDIX 4 - Physico-chemical Characterization of Gypsic Xerosols, Spain