Novel potassium solubilizing bio-formulation improves nutrient availability, fruit yield and quality of pomegranate (Punica granatum L.) in semi-arid ecosystem

A carrier based bio-formulation of potassium solubilizing fungi, Penicillium pinophilum, MCC0114 was evaluated for its effect on availability of K and P, plant nutrient status, fruit yield and quality of pomegranate under field condition. Soil inoculation with this bio-formulation was found to improve availability of K and P in soil and plant nutrient status that increased fruit yield by 35% with perceptible improvement in fruit quality. The impact of bio-formulation on fruit yield and quality was much higher, when supplemented with insoluble K bearing mineral. The highest yield (27% higher than that recorded from the application of potassic fertilizer at recommended dose) and cost-benefit ratio of 1:2.60 were recorded with the conjunctive use of bio-formulation and insoluble K bearing mineral at the rate of 20 g K2O tree(-1). Higher dehydrogenase, alkaline and acid phosphatase activity, microbial biomass carbon content and population of Penicillium spp. in inoculated soil were due to rhizospheric colonization of P. pinophilum in the bio-formulation indicating its suitability for pomegranate.