Rhizosphere microorganisms (RMs) are important in crop production but, they have been badly affected by agrochemicals. Hence, restoration of beneficial RMs is required for soil rehabilitation. This study was designed to isolate indigenous soil microbes (ISM) and tested their survival in a nutrient-enriched broth culture medium (BCM). BCM was prepared by using ingredients i.e., sugarcane molasses,
... [Show full abstract] rice bran and water. A virgin soil sample was collected from Udawalawe, Dry zone of Sri Lanka and it was introduced to BCM and incubated at ambient conditions for six months. After that, BCM was filtered and stored in amber colour containers. The standard dilution plating method with specific culture mediums was followed to identify RMs present in BCM and recorded their colony-forming units (CFU). Accordingly, BCM was tested for storage conditions i.e., ambient condition, refrigerator (4°C), sunny and darker. In vitro results indicated that ISM viz. Anaerobic nitrogen-fixing bacteria, Herbaspirillum spp., Root nodule-Rhizobium spp., Azospirillum spp. and Phosphate solubilizing bacteria can be survived in the developed BCM for more than six months with the average CFU/ml counts of 7.00×10 58 , 8.75×10 58 , 7.50×10 58 , 15.00×10 58 and 57.00×10 58 respectively. The direct sunlight exposure reduced the population of ISM in BCM. In darker conditions, microbes were survived successfully. Under the refrigerator condition, ISM was sustained well. The ambient condition was better for the prolonged survival of ISM in a cost-effective way. For future advancements, in vitro morphological and species-level characterisation studies and field-level studies on effectiveness as an SMI are needed.
