Soil Solution Chemistry
The application of granular lime with a gradual release of calcium will not cause the same boost to soil solution levels of calcium. It should be kept in mind that the aim of a Limeflo application is to provide a large increase in the level of calcium (and also pH) in the soil solution even though this will just be temporarily high. There are many advantages to a long-term significant pH lift in acid soils and the use of granular lime is discussed in the section titled "The Value of Granular Lime".
Cation exchange sites are "filled" with cations – either base or acid, these are in equilibrium with the soil solution itself. The equilibrium means that the levels of cations on cation exchange sites buffer any change in soil solution. As cations are added gradually to soil solution for example calcium ions from granular lime, these will be exchanged with cations on the exchange sites. In low pH soils, this means that the calcium ions will generally be replaced with hydrogen, sometimes aluminium or magnesium. There is no big initial boost to soil solution calcium levels or pH, just a gradual rise in pH and calcium levels as the buffering capacity of the exchange sites is worn out (calcium levels are built up). It may take a large application of granular lime to achieve an appreciable effect on soil conditions and biological activity.
Limeflo releases calcium faster than can be buffered by the cation exchange system. Therefore there is the potential for a large boost in soil solution calcium levels and pH for a sufficient period to enhance earthworm activity, soil biological activity in general, legume nodule formation and activity, and pasture nutrient uptake and production.
It should be noted that the level of granular lime required to lift the soil pH by one unit is enormous in heavy soils of very high cation exchange capacity. If a soil has twice the exchange capacity as another it will take roughly twice as much lime to shift the pH the same amount. In such soils, Limeflo is still effective in providing a calcium boost in soil solution at the same rates as recommended for lighter soils.
