Improving phosphorus availability in saline-alkaline agricultural soils through biochar and phosphorus solubilizing bacteria (PSB) inoculation: a greenhouse experiment

Phosphorus (P) is an essential element for life on earth and a limiting nutrient for plant growth. However, its availability in saline-alkaline soils is significantly reduced, adversely affecting plant productivity. Saline-alkaline soil is a widespread problem that severely affects plant growth and productivity. The Parthenium-derived biochar (PB) and Sewage sludge-derived biochar (SSB) were analyzed for pH, electric conductivity (EC), cation exchange capacity (CEC), calorific values (CV), and surface area (SSA). The phosphate solubilizing index (SI; 2.83 mM) and quantitative analysis (521.5 µg ml−1) were suggested that PSB-01 efficient and the strain identified through 16S rRNA sequencing techniques. The experiment was based on completely randomized block design (CRBD) with triplicates. The results revealed that the application of PB, SSB, and PSB-01 significantly improved Spinacia oleracea (S. oleracea) growth as compared to the control. The highest growth was observed in the combined amendments as compared to single once in both 1% and 3%. The highest reduction in cation and anion concentrations was observed in the combined applications of PB, SSB and PSB-01 for 1% and 3%. The combined application of biochar along with PSB-01 can enhance soil properties (pH, CEC, SSA anoins and cations) and promote plant growth, offering a sustainable solution for saline-alkaline agricultural soil. This study employs an innovative approach by combining biochars derived from Parthenium and sewage sludge with phosphate-solubilizing bacteria (PSBs) to address multiple issues simultaneously: mitigating saline-alkaline soil, controlling Parthenium overgrowth, and managing sewage sludge problems.