For agricultural use, the calcium carbonate coarse powder is used to neutralize soil acidity, which can change the PH of the soil layer.
The agricultural limestone/calcium carbonate powder should live up to the following criteria:
A: Purity: the powder should be good calcium carbonate
B: Fineness of granular: 8-80 mesh
C: Water content: less moisture more better.
For the purity, it influences the calcium carbonate ability to neutralize the hydrochloric acid in the soil. Please refer to the standard of Association of Official Agricultural Chemists.
The fineness of the limestone powder can influence the effectiveness of neutralization.
A: Coarser than 8 mesh —- 10% effective
B: Finer than 8 mesh and coarser than 50 mesh —- 40% effective
C: Finer than 50 mesh —- 100% effective
The surface area of the calcium carbonate powder and the degree of combining with the soil will influence the rate at which limestone goes into the soil.
If the limestone powder is finer than 50 mesh, there is still no research to prove the effectiveness the much finer powder brings. The neutralizing effectiveness remains almost same for 50 mesh or 100 mesh or 200 mesh.
As we all know the calcium carbonate is not very soluble in water. So the dryer the calcium carbonate powder, the more effective for neutralizing.