Humic substances of soils and general theory of humification

This work contains results of the latest studies on the composition, structure and properties of humic substances, which are the largest and most important component of organic matter of different types of soils. It should be useful for soil scientists and nature conservationists. Cover......Page 1 Half Title......Page 4 Title Page......Page 6 Copyright Page......Page 7 Preface to the English Language Edition......Page 8 Table of Contents......Page 10 Introduction......Page 12 Composition of Plant Remains and Pathways of their Transformation During Humification......Page 19 Relative Stability of Organic Matter......Page 42 Problems of Separation and Nomenclature of Humic Substances......Page 51 General Remarks......Page 61 Nature of Humic Substances from their Elemental Composition......Page 73 Evaluation of Structure and Some Properties of Humic Substances from Elemental Composition......Page 79 Supplementary Data on the Elemental Composition of Humic Substances and its Change in the Course of Agricultural Exploitation of Soils......Page 91 3. Structural Units and Functional Groups of Humic Substances......Page 102 Acid Hydrolysis of Humic Substances......Page 103 Amino acids and amino sugars......Page 104 Carbohydrate Fragments......Page 111 Oxidation Products of Humic Substances......Page 113 Use of Nuclear Magnetic Resonance (NMR) Data to Describe Humic Substances......Page 122 Functional Groups and Distribution of Oxygen......Page 126 Interaction of Humic Substances with the Mineral Components of Soils......Page 137 Methods for Study of Organo-mineral, Interactions......Page 141 Composition and Properties of Compounds of Humic Substances with Metals......Page 148 Interaction of Humic Substances with Soil Minerals......Page 155 4. Electron and Molecular Absorption Spectra of Humic Substances......Page 163 Electron Absorption Spectra......Page 164 Effect of Storage and Exposure to Light on Absorption Spectra of Humic Substances......Page 180 Nature of Light Absorption by Humic Substances......Page 183 Optical Properties of Humic Substances of Various Soils......Page 188 Infra-red Spectra of Humic Substances......Page 192 5. Molecular Parameters of Humic Substances......Page 210 Minimum Molecular mass from the Data of Chemical Composition......Page 217 Mean Weighted Molecular Mass of Humic Acids from Light-scattering Data......Page 218 Molecular Mass Distribution of Particles of Humic Substances from Gel-filtration Data......Page 219 Electron Microscopic Observations......Page 224 Viscosimetric Data......Page 226 6. Hypotheses Regarding the Structure and Identification of Humic Substances......Page 228 Structural Schemes for Humic Substances......Page 229 Diagnosis and Identification of Humic Substances......Page 240 Humus Status of Soils......Page 246 Indices of Humus Status of Soils......Page 247 Humus Status of Zonal Genetic Series of Soils......Page 250 Humus in Soils of the Non-chernozem Zone of Russia......Page 252 Humus of Desert and Semi-desert Soils......Page 259 Effect of Some Ameliorants on Soil Organic Matter......Page 265 General Theory of Humification......Page 267 Hypotheses Regarding Chemical Mechanisms of Humification......Page 268 Kinetic Theory of Humification......Page 274 Biogeochemical Principles and the Laws of Humus Formation......Page 283 Literature......Page 292 Recent Publications......Page 328 The author has summarised results of the latest studies on the composition, structure and properties of humic substances, which are the largest and the most important component of organic matter of different types of soils. He has examined the group and fractional composition of humus of the principal types of soils of Russia and other countries, highlighted the dependence of their formation on bioclimatic conditions and economic activity of man. A probable structure of humic acids - the most important component of humus - has been proposed and the general theory of humification discussed. Recommendations have been made for forecasting change of the humus state of soils in the course of their agricultural exploitation and for improving the humus state of cultivated soils. The book is addressed to specialists in soil science, agricultural chemistry, nature conservation, agronomy, hydrochemistry, botany and soil amelioration and to students and post-graduates in these disciplines