LIME REQUIREMENT AND LIMING MATERIALS FOR ACIDIC SOIL

LIME REQUIREMENT AND LIMING MATERIALS FOR ACIDIC SOIL

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  LIME REQUIREMENT FORACID SOIL & LIMING MATERIAL -Rajesh Debnath
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  LIMING ▪ Application oflime. ▪ To neutralise soil acidity and increases activity of soil bacteria. ▪ Oversupply may result in harm to plant life. ▪ Lime is a basic chemical
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  Beneficaial effects of liming Cropyield improvement Nutrient availability Improved microbial activity Improved legume fixation Calcium and magnesium addition
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  Distinct growth rateon same acid soil upon liming
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  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,
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  How to calculate? Usingthe 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])
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  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
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  Lime requirement determination Basedon 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
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  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
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  ▪ 10 mLof 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
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  Adams-Evans Buffer Method Itwas designed for soils that are coarse-textured, with low cation exchange capacities and organic matter contents, and thus low lime requirements
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  ▪ Use thesoil 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.
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  LIMING MATERIAL A limingmaterial is any compound that is capable of increasing the soil ph by combining with the H+ ions in the soil solution
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  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
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  Effect of finness ofthe liming material
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  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.