Impact Assessment of Varied Agroclimatic Conditions on Phosphate Solubilization Potential of Fungi in Fermentation and Soil-Plant System

In this work, two phosphate solubilizing fungi viz., Aspergillus tubingensis S33 and A. niger S36 were studied under different physiochemical and nutritional parameters in the lab, and in vitro under soil-plant experiments at two very distinct agro-climatic conditions viz., Banasthali, Tonk (Rajasthan), and Dwarahat, Almora (Uttarakhand), India. Phosphate-solubilizing capability was checked with different carbon and nitrogen sources. Maltose, glucose, and fructose were optimal carbon source in A. tubingensis S33 while fructose in the case of A. awamori S33. Amongst nitrogen sources, S33 showed maximum phosphate solubilization with ammonium sulfate while, S36 with ammonium sulfate and sodium nitrate. Ammonium was more stimulating than nitrate as the chief nitrogen source. In vivo experiments revealed that solubilization was noticeable at all the temperatures, but optimal temperature was 25–35°C. The optimal initial pH for Tricalcium Phosphate (TCP) solubilization was 8.0. The ideal concentration of TCP for solubilization was 7.5 g∙l⁻¹. The application of both strains in two different geographical sites exhibited a significant (p<0.05) rise in wheat growth, grain yield, and available Phosphorus (P). Fungal inoculation with TCP amendment exhibited a more notable effect on growth, yield, and soil fertility than control. This study support that these isolates will be able to work efficiently in varied climatic conditions and will show consistent efficiency on field application.