1. Purity expressed as %
2. Fineness based on mesh size
| Mesh size | Reactivity |
|
| Coarser than 20 mesh |
very little effect after 18 months |
| 30-60 | took 6-18 months to neutralize
the acidity that was neutralized
in 1 month by 80 mesh |
| 100 | reacts very rapidly |
3. Neutralizing Value of Different Liming Materials
| | Material | CaCO3 equivalent |
| Calcite | CaCO3 | 100 |
| Dolomite | CaCO3  MgCO3 | 109 |
| Hydrated | Ca(OH)2 | 136 |
| Burned | CaO | 179 |
*M.W. = Molecular Weight
| Example using Ca(OH)2 |
|---|
 |
4. Degree of Mixing and Reaction Time
Lime is very insoluble, therefore, it needs to be mixed throughout the root zone. If the recommended amount of limestone is properly mixed with the soil, planting may follow without delay because enough fine particles are present in limestone to raise soil pH immediately above toxic Al and Mn levels and to correct a Ca deficiency. In the past it was recommended that limestone be applied 2 to 3 months prior to planting. Because of improved tillage equipment for incorporating limestone and improved limestone quality this recommendation is no longer necessary. When limestone is properly incorporated into the soil, liming may be done anytime between the harvesting of one crop and the planting of the next.
By Gerald Kidder, Professor, Soil and Water Science Department, University of Florida
