Every agricultural liming material is sold on two properties: how much acidity it can neutralize, and how quickly. The first is calcium carbonate equivalent, or CCE. The second is fineness, reported as the share of the material passing a set of sieves. Most states combine the two into a single index, so a buyer can compare products on what they actually deliver to the soil.
What is calcium carbonate equivalent?
CCE expresses a material’s acid-neutralizing capacity relative to pure calcium carbonate, which is the reference. A limestone with a lower CCE neutralizes less acidity per ton, usually because it carries impurities that do nothing for soil pH. Burnt lime, hydrated lime and dolomite rate above pure calcium carbonate — not because they are purer, but because their chemistry neutralizes more acid per unit of mass.
CCE is measured on the product by a laboratory method. It is related to a carbonate assay but is not the same thing: the assay says how much CaCO3 is present, while CCE says what the whole material does to acid. University of Minnesota Extension’s guide to liming materials shows how one state combines CCE and fineness into the figure lime is sold on.
Why fineness matters as much as CCE
Lime works only where it dissolves, and it dissolves from its surface. Fine particles react within the season; coarse particles react slowly and contribute little in the first year. That is why lime labels and state rules report fineness as the percentage passing specific sieves, and why two products with the same CCE can behave very differently in the field.
ECCE, ENV, ENP: one index, several names
States and universities combine CCE and fineness into one figure under different names: effective calcium carbonate equivalent (ECCE), effective neutralizing value (ENV), effective neutralizing power (ENP) and others. Each weights the sieve fractions by how much of that fraction is expected to react, then applies the CCE. The sieves and weights differ from state to state, so compare products only on the same index, calculated the same way.
Comparing liming materials on cost
Once two products are on the same index, divide the delivered and spread cost of each by its effective value. The cheaper ton is not necessarily the cheaper neutralization: a low-cost product with low fineness or a low CCE needs more tons to meet the same recommendation, and every extra ton is hauled and spread.
Calcium and magnesium belong in the comparison too. Dolomitic lime supplies magnesium along with its neutralizing value; a high-calcium material supplies calcium and very little magnesium. Which one fits depends on the soil test, and the rate belongs to the soil test and your agronomist.
Where natural aragonite fits
Oolitic aragonite is a high-calcium material. AragoCor’s analysis is 96.17% CaCO3 and 0.24% MgCO3, representative analysis by ASTM C 25, so it supplies calcium with very little magnesium. AG-CAL, the agricultural grade, is sized 0.2–0.5 mm as a published range, and the material carries the OMRI crop fertilizer listing avw-23214.
AragoCor’s data sheet reports composition and sizing rather than a state liming index. The figure to compare on is a CCE and fineness on your state’s basis, and it is worth asking for before any purchase. The aragonite vs. agricultural lime page sets the two materials side by side.
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