LAVA pumice stone can be used as a soil improver on soils that lack an ideal grain size composition and present mild drainage or air permeability problems. LAVA pumice stone makes heavy clay soils more porous, hence improving drainage, and reduces the average pore size in sandy soils ultimately increasing their water capacity, i.e. their ability to retain water. In addition, LAVA pumice stone increases the total porosity of sandy soils, which is very low by default (about 35-40%), thus improving their air permeability.
To sum up, incorporating LAVA pumice into soil doesn’t directly impact its pH or fertility due to its natural, chemically inert properties. Yet, it indirectly enhances soil fertility by improving drainage and aeration, which in turn boosts nutrient accessibility and facilitates extensive root growth within a larger soil volume.