Isolation and Morphological Identification of Aspergillus Species from Some Cultivated Soils in Maiduguri, Nigeria

Background and Objective: Aspergillus is an important genus of filamentous fungus distributed worldwide with great important uses in agriculture, the environment, food industries and human health. Despite the economic importance, there is no research work reported on Aspergillus in soil from the study area. This present work was carried out to isolate and identify the various species of Aspergillus and their diversity in some cultivated soils. Materials and Methods: Representative soil samples were collected from six cultivated soils at 0-15 cm soil depth viz; vegetable crops (onion and tomato); cereal intercropped with legumes (millet/cowpea and millet/groundnut) and orchard (mango and cashew) from the Faculty of Agriculture Teaching and Research Farm and farms around the campus. Each sampled soil was analyzed for physicochemical properties and isolation of Aspergillus using the dilution plating method. The isolates were counted and identified at the species level based on morphological characteristics. Descriptive statistic was used to analyzed data and results presented in percentage. Results: Five isolates were identified; Aspergillus niger, Aspergillus flavus, Aspergillus glaucus, Aspergillus versicolor and Aspergillus ustus. Variation in species abundance amongst the sites was observed. Aspergillus niger, Aspergillus flavus and Aspergillus versicolor were common species to all the fields and thus recorded a total percent abundance of (30, 28 and 21%). Aspergillus glaucus and Aspergillus ustus had 12 and 9%, respectively and failed to appear in tomato fields. Conclusion: The results obtained indicated the presence of Aspergillus from the studied area. The highest number of Aspergillus colonies were recorded under orchards followed by cereal intercropped with legumes while vegetable crop fields recorded the least colony counts.