Kishinev: 1999, 241 p.

Mineralogical composition of main soils of Moldova is investigated. Both traditional methods of investigation and author's elaborations are applied. It is estimated the parameters of mineralogical composition of soils and rocks and its change in the processes of weathering and pedogenesis and as action of anthropogen factors (irrigation, fertilization, etc.). Necessity of principle and possibility of soil mapping based on mineralogical composition are demonstrated. Samples of these maps are presented. Characteristics of main soils on subject of natural reserves of potassium, their genesis and evolution are given. Limitations upon quality of irrigational waters in connection with features of composition of clay minerals are presented. Main factors and processes, affecting properties of mineralogy of Moldova soils, are exposed. Their geological and soil origin is demonstrated. Processes of pedogenesis themselves are the different forms of the common eluvial process which is resulting in decomposition of practically all minerals and relative quartz accumulation. The eluvial process is developing by stages from younger to more ancient soils.

This book is intended for specialists in the field of soil minerology, soil scientists, geologists, agrochemists, ameliorators, ecologists and also for teachers and students.

© V.E. Alekseyev, 1999

               CONTENTS

        FOREWORD OF THE EDITOR                                         5
        INTRODUCTION                                                   6
PART 1. SOIL-GEOGRAPHICAL AND GEOLOGICAL-
        GEOMORPHOLOGICAL CHARACTERISTIC OF REGION                      9
1.1.    Soil cover                                                     9
1.2.    Superficial sedimentary rocks: age
        and connection with modern geography of soils                  9

PART 2. DIAGNOSTICS
        METODS OF APPROACH OF PRINCIPLE AND NEW
        METHODICAL WORKING OUT IN DIAGNOSTIC OF
        MINERAL AND SOIL PROCESSES                                    13
2.1.    Investigation of silicate fraction of soils                   14
2.2.    Conjucated investigation of primary and ciay minerals         14
2.3.    Method of deep fractionation of silicate part
        of soils and rocks                                            14
2.4.    Method of quantitative analysis of primary minerals           15
2.5.    Quantitative evaluation of clay minerals                      16
2.6.    Mineralogical criteria of evaluation of uniformity
        of parent rock                                                17
2.7.    Method and mineralogical criteria of diagnostic
        of podzolization, lessivage and clayization                   18
2.8.    Method of determination of balance of silicate minerals
        under weathering and pedogenesis                              20
2.9.    Illite-smectite indexes as criteria of intensity and tension
        of eluvial process                                            22

PART 3. PARAMETERS
        PARAMETERS OF MINERALOGICAL COMPOSITION
        OF SOILS AND ITS TRANSFORMATION UNDER
        WEATHERING AND PEDOGENESIS                                    24
3.1.    Parent rocks                                                  24
3.1.1.  Composition of minerals                                       24
3.1.2.  Granulometry and mineralogy                                   26
3.1.3.  Parent rocks as weathering crusts                             30
3.2.    Zonals soils                                                  33
3.2.1.  Forest soils                                                  33
3.2.1.1.Status of studying of mineralogical composition               33
3.2.1.2.Mineralogic and elemental composition, their changes under
        pedogenesis                                                   34
3.2.1.3.Balance of primary and clay minerals                          43
3.2.1.4.Ratio of processes podzolization, lessivage and clayzation    51
3.2.2.  Chernozems                                                    56
3.2.2.1.Status of studying of mineralogical composition               56
3.2.2.2.Mineralogical and elemental composition, their changes
        under pedogenesis                                             58
3.2.2.3.Balance of primary and clay minerals                          70
3.2.2.4.Calcareous minerals                                           83
3.2.2.5.Processes of transformation of silicate part                  89
3.3.    Azonal soils                                                  95
3.3.1.  Rendzines                                                     95
3.3.2.  Compacted soils                                               96
3.3.2.1.Chernosems compact                                            97
3.3.2.2.Alluvial compact  soils                                      101
3.3.3.  Solonetzes                                                   104
3.4.    Soils in erosional-deluvial sequences                        108
3.5.    Alluvial soils                                               114
3.6.    Parameters of anthropogenic transformation of soil
        mineralogy. Reserves of potassium                            121
3.6.1.  Irrigation of soils. Laboratory modelling                    122
3.6.2.  Illitization as form of nonexchange fixation of potassium
        from fertilisers                                             126
3.6.3.  Mineralogical composition and reserves of potassium          128
3.7.    Soil mapping on base of soil mineralogy                      137

PART 4. FACTORS AND PROCESSES
        THE MAIN FACTORS AND PROCESSES WHICH
        FORM MINERALOGY OF REGION SOILS                              148
4.1.    Geological factors and processes                             148
4.2.    Soil processes                                               153
4.2.1.  Export of carbonates                                         154
4.2.2.  Physical dispergation, chemical and structural
        dispergational transformation and dissolution of silicates   156
4.2.3.  Illitization                                                 162
4.2.4.  Clayization and its compounds                                167
4.2.5.  Lessivage                                                    171
4.2.6.  Podzolization. The problem of its interpretation.
        Eluvial process                                              172
4.3.    Types and species of mineralogical zonality                  179
4.4.    Prognosis of change of some features of soils
        in connection with evolution of their mineralogical
        composition and utilization                                  182

        SUMMARY                                                      186

        ANNEX                                                        191

        BIBLIOGRAPHY                                                 210