Phosphorus solubilizing Bacillus sp. strain MN-54 increased the yield and economic returns of pearl millet due to improved phosphorus use efficiency

Abstract

Phosphorus (P) deficiency is a frequent problem in calcareous soils of Pakistan because of P-fixation, which poses significant threats to pearl millet productivity. The use of P-solubilizing bacteria (PSB) is regarded as a promising approach for improving P-availability in soil-plant systems. However, it needs optimization of P application into the soil. Therefore, this 2-year field study was conducted to optimize P doses in combination with PSB (Bacillus sp. MN54) inoculation to improve phosphorus use efficiency (PUE), yield, economic returns, and grain quality of pearl millet. Five P doses, i.e. 0 (native soil P only - control), 30, 60, 90, and 120 kg P2O5 ha−1 combined with and without PSB inoculated seeds were used in the study. The application of 90 kg P2O5 ha−1 + seed inoculation with PSB improved the grain yield by 36.8% and 36.0% during 1st and 2nd year, respectively. The same treatment significantly improved the PUE, grain protein, zinc (Zn), and total grain P contents compared to the control treatment. Furthermore, the highest economic returns (1053.3 and 1050.5 $ ha−1) and benefit:cost ratio were observed under 90 kg P2O5 ha−1 + seed inoculation with PSB during both years. In conclusion, application of 90 kg P2O5 ha−1 combined with PSB seed inoculation is a pragmatic option to improve P uptake, grain yield, PUE, grain quality and economic returns of pearl millet grown on calcareous soils.