الفهرس 
SoilsOnly 14 pages are availabe for public view
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Abstract
The present study aims at analysing the rawdahs vegetation around Riyadh area, central Saudi Arabia.(Al-Kharj, Binban and Al-Khuraym rawdahs) . It aims also at assessing the role of the environmental factors that affect the distribution of the plant communities, and to evaluate the size distribution of the populations of some common shrubs and trees, and the nutritive status of the frequent species . One hundred stands were selected to represent the prevailing environmental variations in the study area. (45 stands in Al-Kharj, 30 in Binban and 25 in Al-Khuraym) . In each stand, a list of species was recorded, and a soil sample was collected. The species cover (m/100m) was estimated in each stand usingthe line-intercept method. Samples of the above ground parts of 50 frequent species were collected for estimating the content of the important nutrients (inorganic and organic) in order to evaluate the nutritive values of these species within the study area. The matrix of stands X species was classified using TWINSPAN and ordinated using DECORANA techniques. The relationships between the vegetation and environmental variables were assessed statistically. Some of the diversity indices were calculated for the recognized vegetation groups in order to judge their relationships with other community and environmental properties. Size frequent distribution of six common shrubs and trees were studied using the dimension analysis. The height and several crown diameters of each individual were estimated.