Determination of Acid Buffering Capacity of Soils.

Many soils have too high pH for acid loving plants to grow optimally.  Hence, it becomes necessary to reduce soil pH accordingly. The causes of high pH are overliming, free Ca/Mg carbonate parent materials and high concentrations of OH^-1, HCO₃^-1 and CO₃^-2. There are many organic and inorganic materials that are used to reduce soil pH. But there is a lack of a rapid method to determine the amount of acidifying materia(s) that can be applied to soils of different texture, CEC and organic matter content to reach a target pH.  The objective of this study was to develop a rapid laboratory method that will determine the amount of an acidifying material(s) needed to lower a soil pH.  Soil samples were equilibrated with 0.05M H<sub>2/sub>SO₄ and pH was measured in H₂O, KCl and CaCl₂.  Also, soil samples were equilibrated with different concentrations of (Al)₂(SO<sub>4/<sub)₃ and FeSO₄ and pH was measured. An inverse relationship to lime requirement of soils was developed that is similar to a lime requirement procedure to determine the amount of acidifying material(s) needed to reach a target pH.