In the region of altillanura (Colombia, Orinoquia) as well as other regions of the world (Brazilian cerrado, Florida US, east Asia, etc) the kind of soils of these places are Oxisoils, which are highly saturated with Al, Low cationic base saturation and as well, are the most desilificated soils, the standard procedure is to amend those kind of soils with rich lime amendments in order  increase pH but this practice also bind the available phosphorum to the soil, turn it into a non-soluble phosphorus, The silicon amendments are aimed to achieve the same objectives as the lime amendments without the binding phosphorus to the soil problem and also dissolving the cationic base but from a cheap silicon source, in this case, pure silica sand (SiO2)