Phosphorus Solubilization under Organic and Inorganic Sources of P in Red and Alluvial Soils and Estimation of Phosphorus Solubilizing Power

Abstract

Phosphorus (P) is the most essential element for energy currency (ATP to ADP) in plant system. Phosphorus fixation is the main problem in red soil due to formation of iron phosphate (Fe-P) and aluminium phosphate (Al-P) resulting low P availability. Technological intervention is needed for utilizing indigenous rock phosphate (RP) as P-fertilizer. Considering this background present investigation was undertaken using phosphorus solubilizers namely, PSB1 (Burkholdaria cariabensis) and PSB2 (Burkholdaria cepacia), RP sources (Udaipur and Purulia) and organic sources [farmyard manure (FYM) and vermicompost (VC)] in red and alluvial soils for increasing P availability. Changes in soil reaction, available P, solubilizing power of P (Ca-P and Fe-P) and acid and alkaline phosphatase activities were recorded under laboratory incubation experiment of 60 days. Lowest pH (6.44) was observed at 60 days after incubation (DAI) in alluvial soil, whereas lowest pH value (4.29) was recorded at 60 DAI in red soil. Effect of FYM on alkaline phosphatase activity was higher as compared to VC applied treatments under both the soils. The activity of alkaline phosphatase activity at different days of interval followed the order of 15 DAI < 30 DAI < 45 DAI < 60 DAI in both the soils. The maximum solubilized P was recorded at 60 DAI in red soil (18.8 mg P kg-1)
and alluvial soil (23.6 mg P kg-1). The FYM treated soils recorded more solubilized P over combined effect of VC and RP treated soil. Co-inoculation of PSB1 and PSB2 resulted better P solubilization as compared to single application. Co-inoculation of PSBs with FYM and VC resulted in higher soluble P in both the soils. The P solubilization was higher from Ca-P as compared to Fe-P irrespective of soil types. Co-inoculation of PSBs with FYM or VC could be a technological intervention for supplement use of RP as P-fertilizer.