Effect of biochar and phosphate solubilizing bacteria on growth and phosphorus uptake by maize in an Aridisol

Abstract

Phosphorus (P) availability is limited to crop plants especially in alkaline calcareous soils due to formation of various precipitates. In such soils, use of P solubilizing bacteria (PSB) along with suitable organic amendment such as biochar (BC) might be the possible solution to provide suitable P concentration to plants. Interactive effect of PSB, BC (0 and 2% w/w), and three application rates of P fertilizers (no fertilizer, half dose, full dose) on P availability and plant growth in a calcareous soil was investigated. The maize (Zea mays L.) seeds were primed with PSB in sugar solution and later sown in clay pots filled with soil (10 kg) and mixtures of BC and fertilizers. Three plants were maintained in each pot and grown for 45 days. Soil parameters such as soil pH, EC, nitrogen (N), and Olsen’s P concentrations were determined after harvesting the plants. The plant growth, biomass, P, and N concentrations in plants were also determined. The results depicted that the PSB-primed plants grown in biochar-amended soil supplied with half and full fertilizers showed maximum growth. No significant effect on the seed germination was observed, but the uptake of P was high in those plants where PSB and BC were applied as a cumulative treatment. Only PSB treatment also showed better results except in no fertilizer treatment as compared with PSB + BC + no fertilizer treatment where BC provided P. The plants yielded higher biomass with full fertilizer doses, but significant and maximum increments were observed in BC + PSB + full fertilizer treatment. Similarly, the uptake of N was high in BC treatment plants as compared with the PSB and control. The application of BC and inoculation of PSB can reduce the demand of fertilizer as well as can be proved as a natural conditioner that can sustain and improve the soil’s physical, chemical, and biological conditions. However, field investigations under different agroclimatic conditions are required before final recommendations.