During the last decades a large area of irrigated lands in Syria has been shifted from extensive cropping to intensive agriculture. Many kinds of soils became incapable to supply high yield crops by their micronutrients requirements. Therefore, the deficiency of Zn, B, Mn and Fe was mentioned in this soil. Humic substances influence micronutrients availability through chelating, which can either increase or decrease the availability of the micronutrients (MN). In this framework, two pot experiments were carried out in a greenhouse at the University of Plymouth (2006) to investigate the effect of a commercial humic substance (HS) on the micronutrients availability of: Fe, Mn ,Zn & Cu in two composite surface soil samples collected from Vertic Cambisols ,southwest of Syria & from Dystric Cambisols, southwest of England.