Most soils of the world contain only small amounts of inorganic sulfur (S) compounds compared to the amounts of organically-bound S. The synthetic inorganic chemistry of S is complex because S, like few elements, can bond with itself and other elements in the same compound. The tendency for S-S bonding also decreases at higher S oxidation states-states that are stable in the aerobic conditions of most agricultural soils. Since ion adsorption decreases the electrostatic potential in the plane of adsorption, each increment of adsorption makes the surface less favorable for further adsorption. Sulfate adsorption by tropical soils varied according to their dominant mineralogy in the order: amorphous hydrated oxides > crystalline oxides > kaolin clays> 2:1 clays. The negative charge of Oxisols and Alfisols increases during SO4 2- adsorption. The relative magnitude of the reactions varies with the amount of SO4 2- added, type of cropping, soil properties, and climatic conditions.
|Title of host publication||Sulfur in Agriculture|
|Editors||M A Tabatabai|
|Publisher||American Society of Agronomy|
|Publication status||Published - 1986|