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Diversity of arbuscular mycorrhizal fungi (AMF) of culturally protected forest, agroforestry practices, and monocropping lands has been investigated in Wensho and Shebedino districts of Sidama Zone in Southern Ethiopia. Rhizosphere soil and root samples of plant components from each land use type were analyzed for spore density, diversity and AM-root colonization. Except some non-mycorrhizal plants, all plants surveyed in the three land-use types showed AMF colonization ranging from 50 to 91%. A total of 29 AMF morphospecies, belonging to nine genera (Acaulospora, Glomus, Claroideoglomus, Funneliformis, Pacispora, Septoglomus, Rhizophugus, Scutellospora and Gigaspora), were identified in the rhizospheres of selected plants in the three land uses. Spores of four genera Rhizophugus, Glomus, Funneliformis, and Acaulospora had higher spore production, accounting for 36.22%, 21.20%, 19.39%, 17.54% and 11.74% of the total number of spores respectively. One-way analysis of variance (ANOVA) showed that spore density and root colonization of different AM structures varied greatly among plant species both within and between different land-use types. Spore density was higher in culturally protected forest and AM colonization was higher in the agroforestry. The lowest number of spores and the lowest percentage of root colonization were recorded in cropland. When land use types were considered separately or together no significant correlation between spore densities and AM colonization was observed. The result of the study indicates that monocropping reduces spore density and AM colonization in comparison with the culturally protected forest and the agroforestry.

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In Sidama, agroforestry represents land-use systems with deliberate management of multipurpose trees and shrubs that grow in intimate association with annual and perennial agricultural crops and/or livestock. The interaction of microbiota with the trees, shrubs and crops make the system fertile, productive and sustainable. One of the beneficial microbiota which has symbiotic association with most of the plants in agroforestry is arbuscular mycorrhizal fungi (AMF). In November and December of 2012, root and rhizosphere soil samples of 21 plant species from nine peasant associations (PAs)(villages within districts where 300-500 families live) were collected from the agroforestry practices in Sidama of Southern Ethiopia for the determination of diversity and abundance of AMF under selected soil parameters and plant species density. Findings on the diversity of AMF based on soil properties showed that at moderate to low P and N concentrations the rate of AMF root colonization and spore density was high in comparison with the rhizosphere soils with the highest P and N concentration. The highest percentage of total AMF colonization was recorded for shade trees Millettia ferruginea (84%) and Erythrina brucei (80%) followed by intercropped perennial crops Ensete ventricosum (86%), Catha edulis (85%) and Coffea arabica (80%) and the lowest percentage AMF colonization was recorded for Rhamnus prinoides (53%) and Colocasia esculenta (52%). Though found in almost all homegarden agroforestry practices and with broad coverage in Sidama agroforestry, some crops and vegetables such Brassica integrifolia and Cucurbita pepo, grown intercropped were found to be non-mycorrrhizal as none of the AMF structures were recorded. The highest number of AM spore population was recorded in rhizosphere soils of Croton macrostachyus (1066±19.33) and Catha edulis (1054±53.12) and the lowest spore density was recorded for Dioscorea alata (100.00±2.89) spore per 100 g of dry soil. The percentage fungal colonization in any individual plant species and spore population in the rhizosphere soils of that species did not correlate to each other and percentage AM root colonization and spore density of all plants in the agroforestry of Sidama were found significantly different at P<0.05 level.