With the improved composition, the addition of Iron (Fe) 3.5% and the low pH, Biohumic Fe 3.5% acts as a biostimulator and provides the plant with the nutrients it needs, fully assimilated by it. The synergistic action of Zeolite and Leonardite make it one of the best soil improvement products. Formatted in pellet form, it is easy to use both for use with fertilizer spreader and by hand - in the cast.