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The Relation of Exchangeable Cations to the Physical Properties of Soils 1
Author(s) -
Baver L. D.
Publication year - 1928
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1928.00021962002000090005x
Subject(s) - citation , relation (database) , base (topology) , agricultural experiment station , soil water , mathematics , chemistry , library science , computer science , agriculture , database , environmental science , soil science , history , archaeology , mathematical analysis
The physical properties of soils are in part dependent upon the size and arrangement of the soil particles. A sandy soil, with its relatively coarse particles, has certain well-defined physical characteristics that are quite different from those occurring in a clay soil which contains a high percentage of fine particles. The pronounced ifference in the physical properties of these two classes of soil is undoubtedly the resul~ of differences in the amount and nature of the colloidal material present. Recent investigations in the field of soil colloids have shown that the physical properties of soils are controlled almost entirely by the colloidal material present (23).8 Some workers have gone so far as say that all physical properties and activities of soils are dependent entirely on the soil colloids. If we consider the complex physical composition of the soil, we can conceive that the physical phenomena observed in soils, such as water-holding capacity, absorption of water, heat of wetting, flocculation and deflocculation, plasticity, etc., may be the result not only of the amount of colloidal matter but also of the nature of the colloids. The colloidal material may be present as discrete particles or as coatings around the larger soil grains. The physical phenomena are perhaps dependent upon the state in which these colloids exist. They may be present in the gel or sol form. The nature of their respective surfaces, upon which their relative chemical and physical activity depends, may be different (6). If the nature of the soil colloidal matter plays an important part in the physical properties of soils, we should expect differences in the activity or behavior of soil colloids as a result of the specific cations that may be found on the absorbing complex. Hissink (~3) states that, "there is an undeniable relationship between the structure of the soil and the relative proportion of the adsorbed bases. As Na comes into evidence, soil structure deteriorates." Gedroiz (~o, ~7) reports that, "the degree of colloidality of any soil depends on the state of saturation of the soil and on the nature of the exchangeable bases." Sokolovski and Lukaschewitsch (24) assert