A Buffer For Acid Requirement Determination Of Soils.
Poster Number 2122
Tuesday, November 5, 2013
Tampa Convention Center, East Hall, Third Floor
Gobena Huluka, Auburn University, Auburn, AL
High soil pH can be a problem to grow acid-loving plants such as blueberries, azaleas and many others optimally. The causes of high soil pH are overliming, free Ca/Mg carbonate parent materials and/or high concentrations of OH-, HCO3- and CO3-2. Even though there are many proven materials that will reduce soil pH, there is a lack of a rapid method to determine the amount of acidifying materials that can be applied to soil to lower the pH. The objective of this study was to develop a rapid laboratory method that will determine the amount of acid needed to lower a soil pH to a target value. Ten mL soil samples were equilibrated with 10 mL of H2O and water pH was measured. Then, 10 mL of either dilute NH4CH3COOH + KH2PO4 + NH4F, H2SO4, FeSO4 or (Al)2(SO4)3, were added to the same soil samples and pH was measured in 20 mL of H2O and buffer (1:1) solutions. Each buffer solution was evaluated for reproducibility, sensitivity and stability. A simple equation analogous to soil lime requirement methods was developed that determined the amount of acid needed to lower soil pH to a target value.