Lime potential

Estimation of Lime Potential of Soil

Lime Potential

The lime potential of soil can be calculated as follows

Lime potential = pH – ½ pCa

pCa             = -log (Ca2+)

Importance

·         Estimation of lime potential is the suggestive of the buffering capacity of soil.

·         It measures the total acidity of soil.

·         Lime potential used to measure the CO2 concentration in soil-air of calcareous soil.

Aim

To estimate the lime potential of soils .

Principle

The soil is shaken with a CaCl2 solution of known strength (1:2 ratio), measuring the activity of Ca2+ ions and pH of the suspension. Lime potential is then calculated by subtracting 1.4, being the value of ½ PCa for 0.01 M CaCl2 as the standard extracting solution in 1:2 (soil: solution) ratio, stimulates the electrolyte level of a non saline soil, at optimum field water content, and more particularly the H+ ion environment, comprising soil solution and plant roots.

Materials Required

·         pH Meter

·         Conical flask

Reagents

·         Buffer solutions at pH 4,7 and 9.2

·         0.01 M CaCl2 solution

Procedure

Weigh 10 gram of soil and transfer into a shaking bottle and add 20 ml of 0.01M CaCl2 solution and shake the content for 30 minutes. After, 30 minutes measure the pH of the suspension by using pH meter. Then calculate the lime potential using the formula.

         Lime Potential          = pH – 1.14

Calculation

Soil Type

pH

Lime potential

Hilly Soil

Wetland Soil

Garden land soil

Result

Soil                          Lime Potential

1.  Hilly Soil                

2.  Wetland Soil

3.  Garden Land Soil

Inference