Soils, Their Formation, Properties, Composition, and Relations to Climate and Plant Growth in the Humid and Arid Regions

Chapter Vi. Physical Composition of Soils.

“ VII. Density, Pore Space, and Volume-Weight of Soils. “ VIII. Soil and Subsoil; Causes and Processes of Differentiation; Humus. “ IX. Soil and Subsoil; Organisms Influencing Soil-Conditions. Bacteria. “ X. Soil and Subsoil in their Relations to Vegetation. “ XI. Water of Soils; Hygroscopic and Capillary Moisture. “ XII. Water of Soils; Surface, Hydrostatic, and Ground water; Percolation. “ XIII. Water of Soils; Conservation and Regulation of Soil Moisture. Irrigation. “ XIV. Absorption by Soils of Solids from Solutions. Absorption of Gases. The Air of Soils. “ XV. Colors of Soils. “ XVI. Climate. “ XVII. Relations of Soils and Plant-Growth to Heat.

3. CHEMISTRY OF SOILS.

Chapter Xviii. Physico-Chemical Investigation of Soils in

Relation to Crop Production. “ XIX. Analysis of Virgin Soils by Extraction with Strong Acids, and its Interpretation. “ XX. Soils of Arid and Humid Regions. “ XXI. Soils of Arid and Humid Regions continued. “ XXII. Alkali Soils, their Nature and Composition. “ XXIII. Utilization and Reclamation of Alkali Lands.

4. SOILS AND NATIVE VEGETATION.

Chapter Xxiv. Recognition of the Character of Soils From Their

Native Vegetation. Mississippi. “ XXV. Recognition of the Character of Soils from their Native Vegetation. United States at large, Europe. “ XXVI. Vegetation of Saline and Alkali Lands.

TABLE OF CONTENTS.

PREFACE xiii

INTRODUCTION, xxiii.—Definition of Soils, xxiii.—Elements Constituting the Earth’s Crust, xxiii.—Average Quantitative Composition of the Earth’s Crust, xxiii.—Clarke’s Table, xxiv.—Oxids Constitute Earth’s Crust, xxiv.—Elements Important to Agriculture; Table, xxv.—The Volatile Part of Plants, xxvi.

CHAPTER I.. Agencies of Soil Formation, 1.—1. _physical Agencies_,

AGENCIES OF SOIL FORMATION, 1.—1. Physical Agencies, 1.—Effects of Heat and Cold on Rocks, 1.—Unequal Expansion of Crystals, 2.—Cleavage of Rocks, 3.—Effects of Freezing Water, 3.—Glaciers; Figure, 3.—Glacier Flour and Mud, 4.—“Green” and “White” Rivers, 4.—Moraines, 5.—Action of Flowing Water, 5.—Enormous Result of Corrasion and Denudation, 6.—Effects of Winds, 8.—Dunes, 8.—Sand and Dust Storms in Deserts, Continental Plateaus and Plains, 8.—Loess of China, 9.—Migration of Gobi Lakes, 9.—Classification of Soils, 10.—Their Physical Constituents, 10.—Sedentary or Residual Soils, 11.—Colluvial Soils, 12.—Alluvial Soils. Diagram, 12.—Character of these Soil Classes, 13.—Richness of Flood-plain and Delta Lands, 14.—Lowering of the Land Surface by Soil Formation, 15.

CHAPTER II.. Chemical Processes of Soil Formation, 16.—2. _chemical

CHEMICAL PROCESSES OF SOIL FORMATION, 16.—2. Chemical Disintegrations or Decomposition, 16.—Ingredients of the Atmosphere, 16.—Effects of Water; of Carbonic Acid, 17.—Carbonated water a universal solvent, 17.—Ammonic carbonate, effect on silicates, 18.—Action of oxygen; on ferrous compounds, 18.—Action of Plants and their Remnants, 19.—A. Mechanical; Force of Root Penetration, 19.—B. Chemical; Action of Root Secretions, 19.—Bacterial Action, 20.—Humification, 20.—Causes Influencing Chemical Action and Decomposition, 21.—Heat and Moisture, 21.—Influence of Rainfall on Soil-Formation, 22.—Leaching of the Land, 22.—Residual Soils, 22.—Drain Waters; River Waters. Tables of Solid Contents, 22.—Amount of Dissolved Matters Carried into the Sea; Amount of Sediment, 24.—Sea Water, Composition of; Waters of Landlocked Lakes, 25.—Results of Insufficient Rainfall; Alkali Lands, 28.

CHAPTER III.. Rock-and Soil-Forming Minerals, 29.—Quartz, Quartzite,

ROCK-AND SOIL-FORMING MINERALS, 29.—Quartz, quartzite, jasper, hornstone, flint, 29.—Solubility of silica in water; absorption by plants, 30.—Silicate Minerals, 31.—Feldspars, their Kaolinization, 31.—Formation of Clays, 33.—Hornblende or Amphibole, Pyroxene or Augite, 33.—Their Weathering and its Products, 33.—Mica, Muscovite and Biotite, 35.—Hydromica, Chlorite, 35.—Talc and Serpentine; “Soapstone”, 36. The Zeolites; Exchange of Bases in Solutions, 36.—Importance in Soils, in Rocks, 38.—Calcite, Marble, Limestones; their Origin, 39.—Impure Limestones as Soil-Formers, 40.—Caves, Sinkholes, Stalactites, Tufa, 41.—Dolomite; Magnesian Limestones as Soil-Formers, 42.—Selenite, Gypsum, Land Plaster; Agricultural Uses, 42.—Iron Spar, Limonite, Hematite, Magnetite, 44.—Reduction of Ferric Hydrate in Ill-drained Soils, 45.

CHAPTER IV.. The Various Rocks As Soil-Formers, 47.—General Classification,

THE VARIOUS ROCKS AS SOIL-FORMERS, 47.—General Classification, 47.—Sedimentary, Metamorphic, Eruptive, 47.—Sedimentary Rocks; Limestones, Sandstones, Clays, Claystones, Shales, 47.—Metamorphic Rocks: Formed from Sedimentary, 48.—Igneous or Eruptive Rocks, Basic and Acidic, 49.—Generalities Regarding Soils Derived from Various Rocks, 49.—Variations in Rocks themselves. Accessory Minerals, 50.—Granites; not always True to Name; Sierra Granites, 51.—Gneiss. Mica-schist, 51.—Diorites, 51.—Diabases, 51.—Eruptive Rocks; Glassy ones Weather Slowly; Basaltic Oxidize Rapidly, 52.—Red Soils of Hawaii, Pacific Northwest, 52.—Trachyte Soils; Light-colored, rich in Potash. Rhyolites generally make Poor Soils, 53.—Sedimentary Rocks, 53.—Limestones, 53.—“A Limestone Country is a Rich Country,” 53.—Residual Limestone Soils; from “Rotten Limestone” of Mississippi; Table, 54.—Shrinkage of Surface, 55.—Sandstone Soils, 55.—Vary According to Cement, and Nature of Sand, 55.—Calcareous, Dolomitic, Ferruginous, Zeolitic, 56.—Clay-sandstones, Claystones, 57.—Natural Clays, 57.—Great Variety, Enumeration and Definition, 58.—Colors of Clays, 58.—Colloidal Clay, Nature and Properties, 59.—Plasticity; Kaolinite Non-plastic, 59.—Causes of Plasticity, 60.—Separation of Colloidal Clay, its Properties, 61.—Effects of Alkali Carbonates on Clay, 62.

CHAPTER V.. The Minor Mineral Ingredients of Soils; Mineral

THE MINOR MINERAL INGREDIENTS OF SOILS; MINERAL FERTILIZERS, 63.—Minerals Injurious to Agriculture, 63.—Minerals used as Fertilizers, 63.—Apatite; Phosphorites of the U. S., Antilles, Africa, Europe, 63.—Phosphatic Iron Ores, “Thomas Slag,” 64.—Animal Bones; Composition and Agricultural Use, 64.—Vivianite, Dufrenite, 65.—Chile Saltpeter, 66. Occurrence in Nevada, California, 66.—Origin of Nitrate Deposits, 67.—Intensity of Nitrification in Arid Climates, 68.—Potash Minerals, 68.—Feldspars not Available, 68.—Depletion of Lands by Manufacture of Potashes, 69.—Discovery of Stassfurt Salts, 69.—Origin of these Deposits, 70.—Nature of the Salts, 71.—Kainit, 71.—Potash Salts in Alkali Soils, 72.—Farmyard or Stable Manure; Chemical Composition, Table, 72.—Efficacy largely due to Physical Effects in Soils, 73.—Green-manuring a Substitute for Stable Manure, 74.—Application of Stable Manure in Humid and Arid Climates, 74.—Minerals Unessential or Injurious to Soils, 75.—Iron Pyrite, Sulphur Balls, 75.—Occurrence and Recognition. Remedies 75.—Halite or Common Salt, 76.—Recognition of Common Salt, 76.—Mirabilite or Glauber’s Salt; in Alkali Lands; not very Injurious, 77.—Trona or Urao; Carbonate of Soda, “Black Alkali,” 77.—Injury Caused in Soils, 78.—Epsomite or Epsom Salt, 78.—Borax, 79.—Soluble Salts in Irrigation Waters, 79.

CHAPTER VI.. Physical Composition of Soils, 83.—Clay As a Soil Ingredient,

PHYSICAL COMPOSITION OF SOILS, 83.—Clay as a Soil Ingredient, 83.—Amounts of Colloidal Clay in Soils, 84.—Influence of Fine Powders on Plasticity, 85.—Rock Powder; Sand, Silt and Dust, 86.—Weathering in Humid and Arid Regions, 86.—Sands of the Humid Regions, 86.—Sands of Arid Regions not Sterile, 86.—Physical Analysis of Soils, 88.—Use of Sieves. Limits, 88.—Use of Water for Separating Finest Grain-Sizes, 89.—Elimination of Clay by Subsidence and Centrifugal Method, Hydraulic Elutriation, 90.—Schöne’s Instrument, 90.—Churn Elutriator with Cylindrical Tube, 91.—Figures of Same, 91.—Yoder’s Centrifugal Elutriator, 92.—Number of Grain-sizes Desirable, 93.—Results of such Analyses, 93.—Physical Composition Corresponding to Popular Designations of Soil-Quality. Table, 96.—Number of soil-grains per Gram, 99.—Surface Offered by various Grain-sizes, 99.—Influence of the several Grain-sizes on Soil Texture, 100.—Ferric Hydrate, its Effects on Clay, 100.—Other Substances, 101.—Aluminic Hydrate, 101.—Influence of Granular Sediments upon the Tilling Qualities of Soils, 102.—“Physical” Hardpan, 103.—Putty Soils, 103.—Dust Soils of Washington; Table, Physical Analyses of Fine Earth, 104.—Slow Penetration of Water, 105.—Effects of Coarse Sand, 105.

CHAPTER VII.. Density, Pore-Space and Volume-Weight of Soils,

DENSITY, PORE-SPACE AND VOLUME-WEIGHT OF SOILS, 107.—Density of Soil Minerals, 107.—No Great Variation, 107.—Volume-weight most Important, 107.—Weight per Acre-foot, 107.—Air-space in Dry Natural Soils. Figure, 108.—May be Filled with Water, 108.—Effects of Tillage. Figures, 109.—Crumb or Flocculated Structure; Cements, 109.—How Nature Tills, 111.—Soils of the Arid Regions; do not Crust, 112.—Changes of Soil-Volume in Wetting and Drying, 112.—Extent of Shrinkage, 113.—Expansion and Contraction of Heavy Clay Soils. Figure, 113.—Contraction of Alkali Soils on Wetting, 114.—“Hog Wallows,” 114.—Physical Analyses of such Soils. Table, 115.—Crumbling of Calcareous Clay Soils on Drying, 116.—Yazoo Bottom, Port Hudson Bluff, 116.—Loamy and Sandy Soils, 117.—Formation of Surface Crusts, Physical Analyses, 117.—Effects of Frost on the Soil; Heaving; Ice-flowers, 118.

CHAPTER VIII.. Soil and Subsoil; Causes and Processes of Differentiation

SOIL AND SUBSOIL; CAUSES AND PROCESSES OF DIFFERENTIATION HUMUS, 120.—Soil and Subsoil ill-defined, 120.—The Organic and Organized Constituents of Soils, 120.—Humus in the Surface Soil, 120.—Soil and Subsoil; Causes of their Differentiation, 121.—Ulmin Substances or Sour Humus, 122.—Sour Soils, 122.—Cultivation Induces Acidity, 123.—Humin Substances, 123.—Porosity of Humus, 124.—Physical and Chemical Nature of the Humus Substances. Table, 124.—Chemical Nature, 125.—Progressive Changes and Effect on Soils, 126.—The Phases of Humification, Wood to Anthracite; Table, 127.—Amounts of Humus and Coal formed from Vegetable Matter, 128.—Figure, From Port Hudson Bluff, 128.—Conditions of Normal Humification, 129.—Eremacausis in the Arid Regions, 129.—Black Earth of Russia; Kosticheff’s Table, 130.—Losses of Humus from Cultivation and Fallowing, 131.—Estimation of Humus in Soils; Unreliability of Combustion Methods, 132.—Grandeau Method, “Matière Noire,” 132.—Amounts of Humus in Soils, 133.—Humates and Ulmates, 134.—Mineral Ingredients in the Humus, 134.—Functions of the Unhumified Organic Matter, 135.—The Nitrogen Content of Humus, 135.—Table for Arid and Humid Soils, 136.—Decrease of Nitrogen Content in Humus with Depth, 138.—Table, Russian River Soils, 139.—Influence of the Original Material upon the Composition of Humus, 139.—Table of Snyder, 139.—Effect of Humus in rendering Mineral Plant Food Available, 140.

CHAPTER IX.. Soil and Subsoil (_continued_), 142.—Organisms Influencing

SOIL AND SUBSOIL (continued), 142.—ORGANISMS INFLUENCING SOIL-CONDITIONS. BACTERIA, 142.—Micro-organisms of the Soil. Bacteria, Moulds, Ferments, 142.—Numbers at Various Depths, given by Early Observers, 142.—Investigations of Hohl; Mayo and Kinsley. Tables, 143.—Multiplication of the Bacteria, 144.—Aerobic and Anaerobic Bacteria, 144.—Food Materials required, 145.—Functions of the Bacteria, 145.—Nitrifying Bacteria. Figures, 146.—Conditions of their Activity. Table, 146.—Effects of Aeration and Reduction, 147.—Unhumified Organic Matter does not Nitrify, 148.—Unhumified Vegetable Matter, Functions in Soils, 148.—Denitrifying Bacteria. Figures, 148.—Ammonia-forming Bacteria. Figures, 149.—Alinit, 149.—Effects of Bacterial Life on Physical Soil Conditions, 149.—Root-bacteria, or Rhizobia of Legumes, 150.—Figures of Root Excrescences and Corresponding Bacteroids, 152.—Varieties of Forms, 154.—Mode of Infection, 154.—Cultural Results, 155.—Table Showing Increased Production by Soil Inoculation, 155.—Other Nitrogen-absorbing Bacteria, 156.—Distribution of Humus in the Surface Soil, 157.—Fungi, Moulds and Algae, 157.—Animal Agencies—Earthworms, Insects, Burrowing Quadrupeds, 158.

CHAPTER X.. Soil and Subsoil in Their Relations to Vegetation,

SOIL AND SUBSOIL IN THEIR RELATIONS TO VEGETATION, 161.—Physical Effects of the Percolation of Surface Waters, 161.—Chemical Effects; Calcareous Subsoils and Hardpans, 161.—“Rawness” of Subsoils in Humid Climates, 162.—Subsoils in the Arid Region, 163.—Deep Plowing and Subsoiling in the Arid Region; examples of Plant growth on Subsoils, 164.—Resistance to Drought, 167.—Root System in the Humid Region, 168.—Figures of the Root System of an Eastern (Wisconsin) Fruit Tree, 168.—Comparison of Root Development in the Arid and Humid Regions, 169.—Prune on Peach Root, 169.—Adaptation of Humid Species to Arid Conditions, 169.—Grapes, 170.—Kentucky and California Maize, 175, 176.—Hops, 172.—Deep-Rooting in the Arid Region, 174.—Goose Foot and Figwort, 174.—Importance of Proper Substrata in the Arid Region, 173.—Injury from Impervious Substrata. Figure, 177.—Faulty Lands of California. Figure, 178.—Shattering of Dense Substrata by Dynamite, 181.—Leachy Substrata, 182.—“Going-back” of Orchards, 182.—Hardpan, Formation and Varieties, 183.—Nature of the Hardpan Cements, 184.—Bog Ore, Moorbedpan and Ortstein; Calcareous and Alkali Hardpan, 184.—The Causes of Hardpan, 185.—“Plowsole,” 186.—Marly Substrata, 186.

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