Int.J.Curr.Microbiol.App.Sci (2017) 6(3): 1752-1762 1752 Original Research Article https://doi.org/10.20546/ijcmas.2017.603.201 Isolation and Identification of Two Potassium Solubilizing Fungi from Arid Soil Ramesh Chand Kasana*, Nav Raten Panwar, Uday Burman, Chandra Bhushan Pandey and Praveen Kumar ICAR-Central Arid Zone Research Institute, Jodhpur-342003, India *Corresponding author ABSTRACT Introduction After nitrogen (N) and phosphorus (P), potassium (K) is the third major essential macronutrients playing a key role in the growth and development of plants. In the world large areas of the agricultural land are deficient in potassium including three-fourth of the paddy soils of China and two-third of the wheat belt of Southern Australia (Meena et al., 2014). The studies carried out on fertility status of Indian agricultural soils however, have shown that 21% of soils are low, 51% medium and 28% high in potassium. Hence about three-fourth agricultural soils require immediate attention (Hasan, 2002 and Meena et al., 2016). As most of the potassium requirements in India is met through the imported fertilizer and with price varying between $460-625 per tonne this makes it a costly proposition. In the year 2009-10, India consumed 55.10 lakh tonnes of murate of potash) of which 42.38 lakh tonnes was used as fertilizer (Kinekar, 2011). It has been also projected that to meet the food demand of 1.3 billion Indians by 2020 the requirement of potassium by Indian agriculture would be 9.52 Mt (Pathak et al., 2010). Also very low percentage of potassium present in the soil either naturally or when applied as synthetic fertilizers is available to plants as most of it is bound with other minerals, and is therefore unavailable to the plants (Goldstein, 1994 and Prajapati et al., 2013). To increase the availability of potassium for plants, huge quantities of International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 3 (2017) pp. 1752-1762 Journal homepage: http://www.ijcmas.com Five potassium solubilizing microorganisms were isolated from the arid soil of Jodhpur, India. Among them two fungal isolates RCKF7 followed by RCKF5 showed higher dissolution capacity towards feldspar, resulting in the release of more potassium compared to the others. Based on morphological characters and sequencing of ITS1–5.8S–ITS2 region the strains were identified as Fomitopsis meliae RCKF7 and Aspergillus tubingensis RCKF5. On further screening of the more potent strain RCKF7, it showed its ability to grow and solubilize potassium over a wide range of temperature (20 to 38 o C) and pH (5.0 to 10.0). The maximum potassium solubilization index was observed at 28 ºC and pH 6.0. Capability of RCKF7 to solubilize phosphorus also rendered it an additional advantage. Furthermore the application of 500 ppm and 1000 ppm feldspar alone or in combination with RCKF7 resulted in more grain yield in wheat as compared to recommended dose of potassium fertilizer. Keywords Potassium solubilizing, Fomitopsis, Aspergillus, Feldspar, Arid soil Accepted: 24 February 2017 Available Online: 10 March 2017 Article Info