Acidification involves four main processes, which are (1) leaching of basic cations (Ca2+, Mg2+, K+, and Na+) from the exchangeable complex of the soil (clay, minerals, humus) and their substitution by protons (H+) and cation acids (SU+, Fe3+, Al3+), (2) accumulation of potentially toxic heavy metals (Co, Cd, Zn) in deeper soil layers, (3) accumulation of aluminum sulfates after saturation of exchange sites with Al ions that allows transportation of acidity to deeper soil layers or groundwaters, and (4) transfer of potentially toxic cation acids (Al, heavy metals) toward groundwater and surface water owing to the increased solubilization of compounds formed by these cation acids under very acidic conditions (Mayer 1998). Acid soil infertility is a major limi­tation to crop production on highly weathered and leached soils throughout the world (Von Uexkiill and Mutert 1995). It is a complex interaction of growth-limiting factors including toxic levels of aluminum, manganese, and iron, as well as deficiencies of some essential elements, such as phosphorus, nitrogen, potassium, calcium, and magnesium, and some micronutrients (Kochian et al. 2004). Among these constra­ints, aluminum toxicity and phosphorous deficiency are the most important owing to their ubiquitous existence and overwhelming impact on plant growth (Kochian et al. 2004).