Four meadows were selected in Riyadh region namely, Kherarh, Al-Masoudi, ShoaibHarimlae and Al-Khabia for this study. Nine wild plants from each meadow were chosen from herbs, shrubs and trees to carry out this work. The obtained results showed that densities of total microbial counts were generally higher in rhizosphere of different wild plants, compared to control (bara) soil. The total microbial counts in the rhizosphere regions of Calotropis procera, Hamada elegans, Lycium shawii and Rhayza stricta plants were relatively higher than those in the rhizosphere of the other studied wild plants. The higher total fungi count in the rhizosphere were observed in Ziziphus snummularia and Calotropis procera plants growing in Al-Masoudi meadow, while the lower total fungi counts were recorded in the rhizosphere of Trigonella anguina growing plant in Al-Khabiah meadow. Azotobacter spp. occurred in higher densities in rhizosphere of Hamada elegans and Tripleurospermum auriculatum plants in Al-Khabiah and Al-Kherarh meadows, respectively. The higher Azospirillum spp. counts were observed in Tripleurospermum auriculatum, Trigonella anguina, Hamada elegans and Acacia gerrardii plants growing in Shoaib Harimlae meadow, while the lower Azospirillum spp. counts were recorded in the rhizosphere of Rhayza stricta in the same meadow. Phosphate dissolving bacteria counts in the rhizosphere of Acacia gerrardii and Lycium shawii plants in Al-Khabiah and Al-Kherarh meadows, respectively exceeded those found in the rhizosphere of other wild plants under different meadows. Pseudomonas sp. occurred in higher densities in rhizosphere of Acacia gerrardii, Ziziphus snummularia and Rhayza stricta in Shoaib Harimlae meadow. The higher Streptomyces spp. counts observed in the rhizosphere Tripleurospermum auriculatum and Launaea capitata plants growing in Al-Khabiah meadow. Cellulose decomposing bacteria counts in the rhizosphere of Tripleurospermum auriculatum, Launaea capitata and Rhayza stricta plants in Al-Khabiah meadow and Calotropis procera in Shoaib Harimlae meadow exceeded those found in the rhizosphere of other wild plants under different meadows.

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