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

“ 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 S...

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...

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, xx...

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...

CHEMICAL PROCESSES OF SOIL FORMATION, 16.—2. _Chemical Disintegrations or Decomposition_, 16.—Ingredients of the Atmosphere, 16.—Effects of Water; of Carbonic Acid, 17.—Carbonat...

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, t...

THE VARIOUS ROCKS AS SOIL-FORMERS, 47.—General Classification, 47.—Sedimentary, Metamorphic, Eruptive, 47.—Sedimentary Rocks; Limestones, Sandstones, Clays, Claystones, Shales,...

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., A...

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 an...

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-sp...

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 Sur...

SOIL AND SUBSOIL (_continued_), 142.—ORGANISMS INFLUENCING SOIL-CONDITIONS. BACTERIA, 142.—_Micro-organisms of the Soil._ Bacteria, Moulds, Ferments, 142.—Numbers at Various Dep...

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.—“Raw...

THE WATER OF SOILS. HYGROSCOPIC AND CAPILLARY MOISTURE, 188.—General Properties, 188.—Physical Factors of Water compared with other Substances. Table, 188.—Capillarity or Surfac...

SURFACE, HYDROSTATIC AND GROUND WATER. PERCOLATION, 215.—Amount of Rainfall, 215.—Natural Disposition of Rain Water, 216.—The Surface Runoff, 216.—Washing-away and Gullying in t...

WATER OF SOILS; THE REGULATION AND CONSERVATION OF SOIL, MOISTURE; IRRIGATION, 234.—Loosening of the Surface, 234.—Effects of Underdrains; Rain on Clay Soils, 235.—Winter Irriga...

ABSORPTION BY SOILS OF SOLIDS FROM SOLUTIONS. ABSORPTION OF GASES, AIR OF SOILS, 267.—_Absorption of Solids_, 267.—Desalination, 267.—Decolorization, 267.—Complexity of Soil-Act...

CLIMATE, 287.—Heat and Moisture Control Climates, 287.—Climatic Conditions, 287.—_Ascertainment and Presentation of Temperature Conditions_, 288.—Annual Mean not a Good Criterio...

RELATIONS OF SOILS AND PLANT GROWTH TO HEAT, 301.—Temperature of Soils, 301.—Water Exerts Controlling Influence, 301.—Cold and Warm Rains, 302.—Solar Radiation, 302.—Penetration...

PHYSICO-CHEMICAL INVESTIGATION OF SOILS IN RELATION TO CROP PRODUCTION, 313.—_Historical Review of Soil Investigation_, 313.—Popular Forecasts of Soil Values, 313.—Cogency of Co...

ANALYSIS OF VIRGIN SOILS BY EXTRACTION WITH STRONG ACIDS AND ITS INTERPRETATION, 340.—Loughridge’s Investigation on Strength of Acid and Time of Digestion, 340.—_Writer’s Method...

SOILS OF THE ARID AND HUMID REGIONS, 371.—Composition of Good Medium Soils; Table, 371.—Criteria of Lands of the Two Regions, 371.—Tables of Soil-Composition in Both Regions, 37...

SOILS OF ARID AND HUMID REGIONS CONTINUED, 398.—_Soils of the Tropics_, 398.—Humus in Tropical Soils, 399.—Investigations of Tropical Soils, 401.—_Soils of Samoa and Kamerun_, 4...

ALKALI SOILS, THEIR NATURE AND COMPOSITION, 422.—Alkali Lands _vs._ Seashore Lands, 422.—Origin, 422.—Deficient Rainfall, 423.—Predominant Salts, 423.—Geographical Distribution,...

UTILIZATION AND RECLAMATION OF ALKALI LAND, 455.—Alkali-resistant Crops, 455.—Counteracting Evaporation, 455.—Turning-under of Surface Alkali, 456.—Shading, 457.—Neutralizing Bl...

THE RECOGNITION OF SOIL CHARACTER FROM THE NATIVE VEGETATION; MISSISSIPPI, 487.—Climatic and Soil Conditions, 487.—Natural Vegetation the Basis of Land Values in the United Stat...

RECOGNITION OF THE CHARACTER OF SOILS FROM THEIR NATIVE VEGETATION. UNITED STATES AT LARGE, EUROPE, 511.—Forest Growths outside of Mississippi; Alabama, Louisiana, Western Tenne...

THE VEGETATION OF SALINE AND ALKALI LANDS, 527.—_Marine Saline Lands_, 527.—General Character of Saline Vegetation, 527.—Structural and Functional Differences Caused by Saline S...

Since the physical and mechanical effects of the agencies mentioned above usually precede, in time, the chemical changes, which are materially facilitated by the previous pulver...

It may be said that in general, the physical agencies of disintegration are most intensely active in the dry or arid regions of the globe, while chemical processes of decomposit...

Since the several stratified rocks, such as sandstones, shales, claystones, clays, limestones, etc., are themselves but the outcome of the same disintegrating and decomposing in...

_Rock-weathering in arid and humid Climates._—From what has been said in the preceding chapters of the physical and chemical agencies concerned in rock-weathering, it is obvious...

_Apatite_; phosphate of lime containing more or less of the chlorids and fluorids of the same metal; the mineral from which the phosphoric acid of the soil is mostly derived. In...

As has already been stated (chapt. 1, p. 10), the general physical constituents of soils are _rock powder or sand_ and _silt_, more or less decomposed according to the nature of...

Aside from the humus-substances the specific gravity of the common soil constituents, taken individually, do not vary widely; kaolinite being the lightest (2.60), feldspar next...

_Soil and Subsoil Ill-defined._—While the general mass of rock debris formed by the action of the agencies heretofore discussed as soil-material, may under proper conditions bec...

Intimately correlated with the humus-substances of the soil, as well as with its temporary contents of the carbohydrates (cellulose, gums and sugars) from which humus is formed,...

_Physical Effects of the Percolation of Surface Waters._—The muddy water formed by the beating of rains on the soil surface will, in penetrating the soil, carry with it the diff...

When it is remembered that from 65 to over 90% of the fresh substance of plants consists of water, the importance of an adequate and regular supply of the same to growing plants...

Since all the water of soils and plants is directly or indirectly derived from the rainfall (including therein snow and hail), some general points regarding this factor require...

In view of the commanding importance of an adequate supply of water to vegetation, the possible and available means of assuring such supply by utilizing to the best advantage bo...

Just as solids have the power of condensing gases upon their surfaces, to an extent proportional to that surface, and therefore to the state of fine division: so fine powders ha...

The natural coloration of soils forms a prominent part of the characters upon which farmers are wont to base their judgment of land quality; hence the origin and value of soil-c...

_Heat and Moisture_ are the main governing conditions of plant growth. In a preceding chapter the relations of soils and plant growth to water have been considered; in the prese...

_The Temperature of Soils._—The rapid germination of seeds, as well as the development of plants to maturity, is essentially dependent upon the maintenance of the appropriate te...

The chemical constituents of soils have been incidentally mentioned and discussed above, both in connection with the processes of soil-formation, and with the minerals that main...

_Hydrous or “zeolitic” silicates_, from which dilute acids can take up the bases potash, soda, lime and magnesia. These silicates may be in either the gelatinous or powdery form...

As stated already, the analysis of soils by extraction with strong acids is intended to enlighten us, not in regard to their _immediate_ productiveness (the “Düngerzustand” of G...

_Strength of Acid used._—Three different strengths of acid were simultaneously employed, viz., chlorhydric of 1.10, 1.115 and 1.160 density. With these the soil was digested at...

of potash, phosphoric acid and nitrogen are adequate, when a large proportion of lime carbonate is present_.—This has already been referred to in connection with the table of so...

_Composition of Good Medium Soils._—In the preceding tables examples have been given of rather extreme types of soils, both rich and poor throughout, and also of such as are def...

supplying the readily assimilable form of nitrogen. Also in favoring the development and activity of the root bacteria of legumes, and of the other nitrogen-gathering bacteria,...

Within the ordinary limits of atmospheric temperatures, and in the presence of adequate moisture, chemical processes active in soil-formation are intensified by high and retarde...

being productive are so by virtue of great depth and relatively high proportions of lime; while in the tropics, the intense leaching process prevents lime from reaching any high...

_Alkali Lands and Seashore Lands._—Alkali lands proper, as already stated, are wholly distinct in their nature and origin from the salty lands of sea-coast marshes, past or pres...

_Alkali-Resistant Crops._—The most obvious mode of utilizing alkali lands is to occupy them with crops not affected by the noxious salts. Unfortunately but few such crops of gen...

_Climatic and Soil-Conditions._—Next to climatic conditions, chief among which are temperature and moisture, the physical and chemical nature of the soil and subsoil is the most...

The application of the above data outside of Mississippi can mostly be verified only in a fragmentary way from such data as are casually given in the reports of State Surveys, a...

_Marine Saline Lands._—While the saline alluvial lands of the sea-coast differ both in their mode of origin and in their nature from the alkali soils or “terrestrial saline land...

possible, since common salt cannot be changed by any practically feasible means. It must be removed by leaching, and this, in the humid countries in which such reclamations have...

A more definite estimate of the amount and kind of sand present in the soil materials can be obtained by washing the _kneaded_ sample into a tumbler, and allowing a thin stream...