This study was achieved to identify some characteristics of clay minerals of
soils in the southern of region (provinces of Daraa, Sweida). Several soils
profiles were selected, forming a toposequence, including the western slope of
Jabal Al Arab a
nd part of Huran plateau which rise about 500-1200m a.s.L.
and rainfall between 250-350mm. These soils usually are planted with rainfed
crops and some trees. Three samples were collected from each profile at depth
0-25 cm, 25-50cm and 50-100cm in order to determine some physical and
chemical of soli characteristics and x-ray and Differential Thermal Analysis
(DTA) were applied to determine the mineralogical composition of clay
minerals. Results indicated that the soils had an clayey texture (37.9 % in Tafas
Dr2 to 67.5% in Tal al Haded SW2), rather high CEC (35-49.4) meq /100g soil,
neutral pH in Sahwa blata SW1 soil (7.1) to slightly alkaline pH (8) in other
soils, low content of organic matter (1)%. CaCO3 ranged of (3.16)% in Sahwa
blata SW1 soil to (25.35)% in Tafas Dr2. Cacium was the dominant cation on
the exchange complex (33.11mq/100g) in TafasDr2, and followed by magnesium
(13.99 mq/100g) in Tal al Haded SW2. Mineralogical analsis by x-ray and DTA
showed the presence of three main clay minerals, Smectites (montmurillonite),
Kaolinite and Mica (probablly illite).
