Background: Mungbean productivity in semi-arid regions is frequently constrained by inadequate phosphorus availability and limited nutrient-use efficiency. Integrating phosphorus fertilisation with phosphate-solubilising biofertilisers may improve phosphorus availability, crop yield and economic returns, while supporting sustainable soil fertility management under resource-limited production systems. Aims: The study aimed to determine the optimum phosphorus dose for economically viable mungbean production in the semi-arid region of Rajasthan and to evaluate the response of mungbean to phosphate-solubilising biofertilisers. Methodology: A field experiment was conducted during the kharif season at the Agronomy Farm of S.K.N. College of Agriculture, Jobner, Rajasthan, using mungbean cultivar RMG-492. Sixteen treatment combinations were evaluated, comprising four phosphorus levels (0, 20, 40 and 60 kg P₂O₅ ha⁻¹) and four biofertiliser treatments (control, PSB, Aspergillus awamori and PSB + A. awamori). The treatments were arranged in a randomised block design with three replications. Yield, economic returns and the quadratic grain-yield response to phosphorus were assessed. Results: Application of 40 kg P₂O₅ ha⁻¹ significantly improved grain yield, straw yield, net returns and the benefit:cost ratio compared with the control and 20 kg P₂O₅ ha⁻¹, while remaining statistically at par with 60 kg P₂O₅ ha⁻¹. The maximum net returns from phosphorus application were ₹58,018 ha⁻¹, with a benefit:cost ratio of 3.61. Among biofertiliser treatments, dual inoculation with PSB + Aspergillus awamori recorded the highest grain yield (1268 kg ha⁻¹), straw yield (3140 kg ha⁻¹), net returns (₹55,029 ha⁻¹) and benefit:cost ratio (3.90). The economically optimum phosphorus dose was estimated at 49.77 kg P₂O₅ ha⁻¹, corresponding to a predicted grain yield of 1236.34 kg ha⁻¹. Conclusion: The study indicates that phosphorus application at 40 kg P₂O₅ ha⁻¹, supported by dual inoculation with PSB + Aspergillus awamori, can improve mungbean productivity and profitability under the tested semi-arid conditions. The estimated economic optimum dose provides a practical basis for phosphorus management in mungbean production.
Venkatarao et al. (Wed,) studied this question.