In vitro screening of rhizospheric Aspergillus strains for potassium solubilization from Maharashtra, India

Abstract

The biggest proportions of K in soil are insoluble minerals and other deposits. Microorganisms play a central role in the natural K cycle and it solubilize by microorganisms through the produc on of acids and it will be available for plant. Their use in agriculture can favor a reduc on in agro-chemical use and support ecofriendly crop production. In the present study, among the nineteen isolates, three fungal isolates from the rhizosphere soils of Maharashtra, India has been found promising solubilizers of potash mineral (Mica). The amount of potassium released from muscovite mica by the isolate (potassium solubilizing fungi) KSF 3 (334.66 mgl-1) at 10 days after incubation, recorded the highest potassium solubilization than control showed 42.81 mgl-1. The significant reduction in pH of the medium of initially adjusted pH of 7.0 i.e. pH 3.80 was recorded by isolating KSF 3. Based on the colonial morphology and microscopic appearance, the selected three efficient fungi were identified as Aspergillus spp. Among all isolates, KSF 3 was showed highest zone of solubilization of potassium from KCl, 50.00 mm followed by KSF 13 (49.63 mm from K2SO4) and KSF 13 (49.33 mm from KCl). There is need of bioactivation of soil K reserves as well as applied K-bearing minerals so as to alleviate the potash fertilizer storage in India. Therefore, the application of potassium solubilizing fungi is a promising approach for increasing K availability in soils.