118 Effect of Phytase Enzyme and Phosphatic Fertilizers on Available Phosphorus in an Alfisol Agropedology 2018, 28 (02), 137-143 * S. T. Shinde, A. B. Jadhav , A. V. Patil, A. L. Pharande, G. D. Patil, B. D. Tamboli and J. M. Khire Abstract: An experiment involving sixteen treatments with four levels of phytase (0, -1 240, 480, 720 IU) and four levels of phosphorus (0, 25, 50, 100 kg ha ) was carried out during kharif 2017 to assess the availability of phosphorus at 0, 15, 30, 45, 60 and 90 days (DAI) after incubation. There was an increase in soil available phosphorus th up to 45 days of incubation either with the application of phytase or P and it reduced -1 after 60 days of incubation. Significantly higher (12.98 kg ha ) available phosphorus -1 was observed with the application of phytase @ 720 IU (16.14 kg ha ) and -1 phosphatic fertilizer @ 100 kg ha within 24 hours of incubation over initial available -1 P (5.20 kg ha ). Application of 480 IU phytase resulted in significantly higher -1 -1 available P (51.98 kg ha ) which was at par with 720 IU (50.45 kg ha ). However, combined application of either 480 or 720 IU phytase along with either 50 or 100 kg P -1 ha through single super phosphate (SSP) had in statistically at par results for available phosphorus. Higher cumulative available phosphorus was recorded with -1 the application of phytase @ 720 IU along with 100 kg P ha through SSP (247.23 kg -1 ha ) throughout the incubation period. Further phosphorus release potential -1 indicated that application of phytase @ 720 IU along with 100 kg P ha through SSP -1 -1 mobilized 0.65 kg ha day phosphorus. Key words: Phytase, phosphatic fertilizer, available phosphorus, P release potential Introduction The availability of P in soil is influenced by pH of the soil. In case of soils with low pH, applied soluble phosphorus get converted into insoluble complexes of Fe and Al phosphates (Yadav and Verma 2012). However, in case of soils with slightly acidic pH, soluble phosphorus gets converted into insoluble complexes of Fe and Al hydroxides. The availability of soil phosphorous (potential or applied) is largely governed by micro flora and soil enzymes. Acid alkaline phosphatase and phytase are the soil enzymes mainly *Corresponding author: (Email: abjadhav1234@rediffmail.com) Department of Soil Science and Agricultural Chemistry, College of Agriculture, Pune-411 005, Maharashtra, India involved in the mineralization of fixed phosphorous. The acid phosphatase and alkaline phosphatase are pre- dominant in acid and alkaline soil respectively (Yadav and Tarafdar 2003). Phytin is an organic form of phosphorus present in plant, soil and organic matter which is hydrolyzed by phytase enzyme. In soil, phosphorus exists both in organic and inorganic form, the organic phosphorus compounds can be classified into i) the inositol phosphate, primarily of plant origin up to 60 % of soil organic phosphorus, ii) the nucleic acids and iii) phospholipids (Aseri et al. 2009). In soils, 20-85 % of the total phosphorus remains in organic form, but