Soil Acidity: Soil pH and Lime Needs

Soil pH is still the most rapid indicator of potential detrimental effects of soil acidity. The use of lime to alleviate soil acidity influences on crop yields without creating problems through over liming requires quantification of the acidity present in a specific soil. The most often used methods for measuring amounts of soil acidity are the following: titration with base or equilibration with lime; leaching with a buffered solution, followed by titration of the acidity present in the leachate; subtracting the sum of exchangeable bases from the soil cation exchange capacity; equilibration with a buffered solution and estimation of acidity by pH change; and extraction with unbuffered neutral salts and analysis of acidity present in the leachate. Equilibration of soil samples with a buffered solution and estimation of acidity by pH change is the most widely utilized method to estimate soil acidity.