Chickpea Biomass, Phosphorus Use Efficiency, and Soil Properties are Enhanced with Integrated Use of Phosphorus Sources, Phosphate-Solubilizing Bacteria, and Rhizobium

The suboptimal production of chickpea in calcareous soils is primarily attributed to the high costs of phosphatic fertilizers and the limited availability of phosphorus (P). This study investigated the most effective approach to enhance P availability and subsequently improve chickpea yield and soil properties. A field experiment was conducted over two growing seasons (2017–18 and 2018–19) to evaluate the effects of varying P source ratios (rock phosphate (RP): single super phosphate (SSP); 0:100, 25:75, 50:50, 75:25, and 100:0), phosphate solubilizing bacteria (PSB), and rhizobium on chickpea biological yield, P use efficiency (PUE), and soil properties. The results revealed that RP:SSP ratios of 0:100 and 25:75 significantly enhanced biological yield (5562 and 5355 kg ha−1), harvest index (34.3 and 33.3%), PUE (31.8 and 28.8 kg−1), soil electrical conductivity (0.369 and 0.345 dSm−1), soil organic matter (1.13 and 1.11%), soil available P (4.45 and 4.38 mg kg−1), and soil total P (305 and 301 mg kg−1), while decreasing soil pH (7.63 and 7.64) compared to the 100:0 ratio. Additionally, PSB application increased biological yield (5246 kg ha−1), harvest index (31.6%), PUE (27.7 kg−1), soil electrical conductivity (0.343 dSm−1), soil organic matter (1.13%), available P (4.82 mg kg−1), and soil total P (334 mg kg−1). Similarly, rhizobium-inoculated seeds exhibited higher biological yield (5264 kg ha−1), harvest index (31.1%), PUE (27.4 kg−1), soil electrical conductivity (0.344 dSm−1), soil organic matter (1.11%), soil available P (4.63 mg kg−1), and soil total P (318 mg kg−1) compared to those without rhizobium. In conclusion, this study recommends the application of P sources at a ratio of RP : SSP at 25:75, in combination with PSB and rhizobium, as a sustainable and effective strategy to improve chickpea yield, PUE, and soil properties of calcareous soils.