The author is a researcher in microbiology and agricultural sciences with research interests in cyanobacteria, soil microbiology, biofertilizers, and sustainable agriculture. Their work focuses on the isolation and characterization of beneficial microorganisms for improving soil fertility and crop productivity in semiarid environments.

Isolation and Morphological Identification of Nitrogen-fixing Cyanobacteria from selected Soils in Maiduguri, Borno State, Nigeria   Cyanobacteria are nitrogen-fixing photoautotrophs with ecological resilience and potential as biofertilizers in sustainable agriculture. This study focused on the isolation, morphological identification, and functional evaluation of cyanobacterial species from agricultural soils in Maiduguri, Nigeria. Soil samples were collected in August 2023, from four sites namely; Farm Centre, Maiduguri-Faria, Alau Farm, and Sheraton Farm and were transported to the Department of Soil Science, Faculty of agriculture where soil physicochemical analysis were carried out. Microbial analysis was carried out at microbiology laboratory, Faculty of sciences. Cyanobacteria were cultured on BG11 medium and screened for nitrogen fixation, phosphate solubilization, indole acetic acid (IAA) production, and biochemical enzyme activities. A total of 38 isolates were recovered, representing five genera: Anabaena (39.5%), Nostoc (28.9%), Calothrix (13.2%),Tolypothrix (13.2%), and Oscillatoria (5.2%). Most isolates were filamentous and heterocystous, especially Anabaena and Nostoc, which exhibited the highest nitrogen fixation rates (73.49 mg/L and 70.56 mg/L). Soil fertility significantly influenced microbial diversity: Farm Centre, with the highest OC (3.55%), supported the most cyanobacterial isolates, while Alau Farm, with the lowest OC (2.19%), had the fewest. Strong positive correlations were observed between cyanobacterial abundance and OC (r = 0.950), P (r = 0.783), and K (r = 0.881). Biochemical assays confirmed catalase, urease, and oxidase activity in most isolates, indicating metabolic versatility and stress adaptation. These findings underscore the biofertilizer potential of indigenous cyanobacteria, particularly Anabaena and Nostoc, for enhancing soil fertility in semiarid regions. Further field validation is recommended to optimize application strategies for nutrient-deficient agroecosystems