Soil Organic Matter

Preface to the Second English Edition

Chapter 1. The Main Stages in the History of Soil Humus Study

The Initial Period of Investigation

The First Half of the 19th Century

The Second Half of the 19th Century

The First Two Decades of the 20th Century

Further Investigations During the 20th Century

The Present Stage in Soil Humus Study

Chapter 2. Contemporary Ideas on the Composition of Soil Organic Matter and the Nature of Humus Substances

Organic Substances of Individual Nature

Strictly Humus Substances in Soil Organic Matter

Methods of Isolating Humus Substances from the Soil

Humic Acids of Soil Humus

Humins of Soil Humus

Fulvic (Crenic and Apocrenic) Acids

Hymatomelanic Acids

Humus Substances as a Complex of High-Molecular-Weight Compounds

General Ideas on High-Molecular-Weight Compounds

Humus Substances of Different Soils as a System of Polymers

Humus Substances of a Single Soil as a System of Polymers

Conclusions

Chapter 3. The Biochemistry of Humus Formation

The Role of Physical, Chemical and Biological Factors

The Origin of Humus Substances

The Possible Participation of Lignin in the Formation of Humus Substances

The Possible Participation of Tannins in the Formation of Humus Substances

The Possible Participation of Cellulose and Other Carbohydrates in the Formation of Humus Substances

The Role of Oxidizing Enzymes in the Synthesis of Humus Substances

The Formation of Humus Substances of Melanoidin Type

The Decomposition of Humus Substances by Micro-Organisms

Humus Formation in Plant Tissue

Experimental Procedure

Nature of the Changes in Plant Residues During Humification

Changes in the Chemical Composition of Plant Residues During Humification

Changes in the Anatomical Structure of Plant Residues During Humification

Nature of Newly-Formed Humus Substances

Changes in Humified Plant Residues Associated with the Activities of Animals

Conclusions

Chapter 4. The Importance of Organic Matter in Soil Formation and Soil Fertility

The Role of Organic Matter in the Weathering and Decomposition of Soil Minerals

The Role of Organic Matter in the Formation of Soil Profiles; Forms of Linkage Between Soil Organic Matter and the Mineral Part of the Soil

The Role of Organic Matter in the Formation of Soil Structure

Soil Organic Matter as a Source of Carbon, Nitrogen and Mineral Plant Nutrients

The Effect of Organic Matter on the Growth and Development of Plants

Vitamins, Auxins and Antibiotics in the Organic Part of the Soil

Physiological Properties of Strictly Humus Substances

Conclusions

Chapter 5. The Natural Factors of Humus Formation

The Role of the Plant Cover in Humus Formation

The Role of Micro-Organisms in Soil Humus Formation

The Influence of Hydrothermal Conditions on Humus Formation

The Influence of Chemical and Physico-Chemical Soil Properties on Humus Formation

Conclusions

Chapter 6. Characteristics of the Organic Matter in the Main Soil Types of the USSR

Main Principles Governing Humus Formation

Humus and Nitrogen Reserves: C:N Ratio

The Composition of Humus in Soils

Forms of Linkage of Humus Substances in Different Soils

Humus of Tundra Soils

Humus of Strongly Podzolic Soils

Humus of Sod-Podzolic Soils

Humus of Gray Forest Soils

Humus of Chernozems

Humus of Chestnut Soils and Solonetses in the Dry Steppe Zone

Humus of Brown Desert-Steppe Soils and Takyrs

Humus of Serozems

Humus of Krasnozems and Lateritic Soils

Humus of Mountain Soils

Conclusions

Chapter 7. Changes in Soil Organic Matter Under Different Soil Management

The Decomposition of Organic Matter Resulting from Ploughing-Up Virgin Soils and Long-Term Cultivation of Annual Crops

Sod-Podzolic Soils

Chernozem Soils in Zones of Moderate and Variable Moisture

Chernozem and Chestnut Soils in Zones of Inadequate Moisture

Irrigated Serozems

Conclusions

Farmyard Manure as a Source of Humus in the Soil

Sod-Podzolic Soils

Chernozem Soils

Typical Serozem

Conclusions

The Accumulation of Organic Matter Under Natural Fallow

The Change of Soil Organic Matter in Rotations with Perennial Herbage

The Accumulation of Root Residues Under Perennial Herbage

The Role of Perennial Herbage in the Formation of Soil Structure

The Dynamics of Humus Substances in Rotations with Perennial Herbage in Different Soil-Climatic Zones

Conclusions

Inhibiting Effect of Fresh Plant Residues on Plant Growth

Changes in Organic Matter Resulting from Complex Systems of Soil Improvement

Chapter 8. Methods of Investigating Soil Organic Matter

A. Methods of Determining the Total Content and Composition of Humus in Mineral Soils

The Determination of Total Organic Carbon in Soils and Solutions by Tyurin's Method

The Determination of the Composition of Humus in Mineral Soils by Tyurin's Method

Rapid Method of Determining the Composition of Humus in Mineral Soils

The Determination of the Optical Density of Humus Substances

The Determination of the Coagulation (Precipitation) Threshold of Humic Acids

B. Methods of Studying the Nature of Humus Substances

Isolation of Humus Substances from the Soil and their Preparation for Investigation

Rapid Methods of Determining Functional Groups in Humus Substances

Methods of Fractionating Humus Substances

The Use of Infra-Red Spectroscopy in Studying the Nature of Soil Humus

C. Methods of Studying the Dynamics of Organic Matter in the Soil

Estimation of the Aerial Mass and Roots of Plants

Biochemical Analysis Applied to the Study of Plant Residues in the Soil

The Dynamics of Humus and Nitrogen in Soils

Methods of Studying the Composition of Organic Matter in Soil Solutions (Aleksandrova, 1960)

A Short Survey of the Main Soil Types in the USSR

The Zone of Tundra Soils

The Zone of Podzolic and Frozen-Taiga Soils

The Zone of Chernozem and Gray Forest Soils

The Zone of Chestnut Soils

The Zone of Semi-Desert and Desert Soils

The Soils of Moist Sub-Tropical Regions

The Soils of Mountain Regions of the USSR

Bibliography

Author Index

Subject Index