Reclamation of acidic soil needs lime application. Hence determination of adequate amount of lime and the appropriate materials as liming materials are discussed.

1. LIME REQUIREMENT FOR ACID SOIL &
LIMING MATERIAL
-Rajesh Debnath

2. LIMING
▪ Application of lime.
▪ To neutralise soil acidity and increases activity
of soil bacteria.
▪ Oversupply may result in harm to plant life.
▪ Lime is a basic chemical

3. Beneficaial effects of
liming
Crop yield improvement
Nutrient availability
Improved microbial activity
Improved legume fixation
Calcium and magnesium addition

4. Distinct growth rate on same acid soil upon liming

5. Lime requirement determination
▪ It is calculated as CALCIUM CARBONATE EQUIVALENT (CCE) - Expression of the acid-
neutralizing capacity of a carbonate rock relative to that of pure calcium carbonate
▪ It is expressed as a percentage.
▪ For pure calcite the value is 100%
▪ pure dolomite the value is 108.5%.
▪ Actual CCE of most limestone varies from these percentages due to impurities in the
rock,

6. How to calculate?
Using the soil lime buffer capacity (LBC):
▪ It is the measure of the amount of soil acidity that must
be neutralized to raise soil pH by one unit.
LR (mg CaCO3 kg-1) = LBC x (target pH- [initial pH-0.6])

7. Equilibrium Lime BufferCapacity (LBCEq)
• LBCEq refers to LBC at equilibrium at five days
• LBC30refers to LBC after 30-minute equilibration
a. Soils with LBC30 ≤ 250 : LBCEq = (3.6709 x LBC30) - 188.25
b. Soils with LBC30 ≥ 250 : LBCEq = LBC30 x 2.90

8. Lime requirement determination
Based on the methods followed and developed by different scientists
following techniques are present for lime requirement determination:
▪ Shoemaker-McLean-Pratt (SMP) Buffer method
▪ Adams-Evans Buffer Method

9. Shoemaker-McLean-Pratt (SMP)
Buffer method
• Was developed for distinctly different soils.
• For use with soils that have large lime requirements and significant
reserves of exchangeable Al

10. ▪ 10 mL of SMP buffer + soil-water slurry
in 1:2.5 ratio
▪ Shaken in a mechanical shaker for 10
minutes, and let sit for 20 minutes.
▪ Swirl, insert electrodes, and read the pH
to the nearest 0.01 pH unit.
▪ Determine lime requirement from soil-
buffer pH and calibration data

11. Adams-Evans Buffer Method
It was designed for soils that are coarse-textured, with low cation
exchange capacities and organic matter contents, and thus low lime
requirements

12. ▪ Use the soil sample previously prepared
▪ Add 10 mL of the Adams-Evans buffer solution to the
sample
▪ Stir thoroughly with a glass rod, allow to equilibrate for
15 minutes and stir again.
▪ Let stand another 15 minutes.
▪ Prepare a diluted solution of the Adams-Evans buffer by
adding 10 mL of distilled water
▪ Check pH. It should read pH 8.00 +/- 0.10.Adjust pH
meter to 8.00.
▪ Insert electrodes into soil-buffer slurry and read pH to
nearest 0.05 pH units.
▪ Use the soil-buffer pH and calibration to determine lime
requirement.

13. LIMING MATERIAL
A liming material is any compound that is capable of increasing the soil
ph by combining with the H+ ions in the soil solution

14. Liming Material
Quality Parameters
▪ TNV: the percentage of the material that can
neutralize acid expressed as CCE of the product.
▪ CCE compares the liming material to pure calcium
carbonate (CaCO3)
▪ The rate of reaction of a liming material is determined
by the particle sizes of the material
▪ ENV is the fraction of the material’s CCE that will react
with soil acidity in the first year of application
▪ The best way to economically compare two lime
products is to look at the cost per ton of ENV obtained
by dividing the cost per ton of limestone by the ENV
• Total Neutralizing Value (TNV)
Calcium Carbonate Equivalence
(CCE)
Fineness
Effective Neutralizing Value (ENV)
• Cost Effective

15. Effect of finness
of the liming
material

17. Thank you
Reference:
• McCart, G.D.,G.W. Hawkins, and G.R. Epperson. 1970. Lime for Acid Soils, what to use and how to
apply, Extension Division,Virginia Polytechnic Institute and State University Publication 405
• Shoemaker, H. E., E. O. McLean, and P. F. Pratt. 1961. Buffer methods of determining lime
requirements of soils with appreciable amounts of extractable aluminum. Soil Sci. Soc.Amer.
Proc. 25:274-277.
• J.B. Peters, K.A. Kelling, E.E Schulte. "choosing between liming material." cocommerce (1996):
336-342.
• Adams, F. and C. E. Evans. 1962.A rapid method for measuring lime requirement of red-yellow
podzolic soils. Soil Sci. Soc.Amer. Proc. 26:355-357.