In order to implement this research soil profiles selected on a toposequence
were systematically collected from different geohorizons. Results indicated that
topographical factors played important roles in determining some soil features
such as th
e depth, texture distribution of CaCO3 and the fertility matter. The
study showed that the soil content of minor element was ranged between
moderate to low, and this may be related to the mineralogical composition of
the parent rock and weathering status and to the use of these elements by the
plants uptake during the long lasting exploitation. The results also indicated
that the decrease of these elements was consistent with the decrease of
elevation, such as heading from the slop to the plain. This probably also due to
the relation between the leaching process and topographical position and to a
less extend to the pH of the soil.
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, th
e 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.
