The situation is further complicated by various interactions among these factors (Foy, 1992). The components of the soil acidity complex have been thoroughly discussed in various publications (Foy, 1984, 1992;Kamprath and Foy, 1985; Tang and Rengel, 2003).
Soils become acidic for several reasons. The most common source of hydrogen is the reaction of aluminum ions with water. The equation for this reaction in very acid soils (pH