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Soils, their formation, properties, composition, and relations to climate and plant growth in the humid and arid regionsHilgard, Eugene W. (Eugene Woldemar)

Science

Soils, their formation, properties, composition, and relations to climate and plant growth in the humid and arid regions

Name: Soils, their formation, properties, composition, and relations to climate and plant growth in the humid and arid regions
Author: Hilgard, Eugene W. (Eugene Woldemar)

Hilgard, Eugene W. (Eugene Woldemar)

Soils

CHAPTER VI.
    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,
        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.

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Soils, their formation, properties, composition, and relations to climate and plant growth in the humid and arid regions

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