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Home > Licensing, Inspections, Certifications & Testing > Licensing > Ag Liming Materials > Agricultural Liming Materials Analysis Explanation

Agricultural Liming Materials Analysis Explanation


Explanation of Terms/Calculations/Purpose

There are three analyses performed on agricultural liming materials (ALM) to determine the Effective Neutralizing Power (ENP) and minimum pounds of ENP per ton. These analyses are (a) Chemical purity or Calcium Carbonate Equivalent (CCE); (b) Fineness or Fineness Index (FI); and (c) Moisture Content.

  1. CCE analysis the amount of calcium/magnesium carbonate or calcium/magnesium oxide contained in ALM. CCE is expressed as a percentage of 100% PURE calcium carbonate. Pure calcium carbonate is the standard by which all ALM chemical purity is compared.
  2. Fineness Index analysis relates particle "sizing" to the neutralizing efficiency of ALM over a three-year period. The analysis is performed by mechanically sieving (both wet and dry sieving) ALM through 8-, 20-, AND 60-mesh sieves for a specified time. ALM passing each sieve size is weighed and divided by the total weight of the sample analyzed to determine the portion (percentage) of ALM which passed through each sieve size. The ALM portion passing the 8-mesh sieve is subtracted from the portion passing the 20-mesh sieve to describe the portion "sized" at 8-20 mesh. The same calculation is done with ALM passing the 20-mesh sieve from the portion passing the 60-mesh sieve. This calculation is not done with the ALM passing the 60-mesh sieve because such material is 100% available within a three-year period. After this process, each sieve or particle size portion is multiplied by its own Fineness Efficiency Factor (FEF) to determine the FI score for each sieve size. FEF is the relative percentage of ALM at specific seive or particle size portion range that will neutralize soil acidity over a three-year period. By adding the resulting fineness indexes for each sieve or particle size together, the total FI is determined.
  3. Moisture content of ALM is determined by drying 600 gram subsample at 110m C (230m F) for 24 hours. Moisture content is expressed as a percentage of the 600 gram subsample. Moisture content is a component in determining the minimum pounds of ENP per ton.

Lastly, ENP is determined by multiplying the CCE by FI. By multiplying the percent ENP by 2,000 pounds and by the ALM's percent dry matter, the minimum pounds of ENP per ton is determined. Minimum pounds ENP per ton equals the pounds of pure calcium carbonate that is considered to be available over a three-year period per ton of the analyzed ALM.The pounds of ENP per ton is required information on the ALM label. The minimum pounds of ENP per ton ALM quality rating listed on an official ALM analysis report is the highest number that an ALM producer, distributor, or dealer can use on a label. The producer, distributor, or dealer may list a lower quality rating on a label to compensate for possible quarry or stockpile variations.

An example of the analytical and mathematical processes explained thus far:

Assumed % Moisture = 5% = 95% Dry Matter && Assumed CCE Analysis = 90%

Fineness Index Analysis Calculations

U.S. Sieve Size

% Passing Sieve Sizes

Difference % Passing 8-20 OR 20-60 Mesh Sieve

X

= Fineness Index

FEF

Per Sieve Size

8

93

93 - 70 = 23

X

0.2

=

4.6

20

70

70 - 46 = 24

X

0.6

=

14.4

60

46

46 - 00 = 46

X

1.0

=

46.0

Fineness Index (FI) = 65.0

% CCE (90) X FI (65) ¸ 100 = % ENP (58.5%)


2,000 lbs. ALM/Ton at 5% moisture X (% ENP ÷ 100) X (% DRY MATTER ÷ 100) = 1,112 Min.


lbs. of ENP per ton (.585) (.95) corrected for moisture


A ton of ALM is priced at $15.00 per ton, the resulting price per pound of ENP is $0.0135 or 1.35 cents. $15.00 1,112 minimum lbs. ENP per ton = $0.0135 or 1.35 cents per lbs ENP.

MDA Contact

Ed Kaiser, Consultant
Ed.Kaiser@state.mn.us
651-201-6275
Pesticide & Fertilizer Management Division