Liming induces carbon dioxide (CO2) emission in PSB inoculated alkaline soil supplemented with different phosphorus sources.

Agricultural land is a major sink of global organic carbon (C). Its suitable management is crucial for improving C sequestration and reducing soil CO2 emission. Incubation experiments were performed to assess the impact of phosphate solubilizing bacterial (PSB) inoculation (inoculated and uninoculated) and soil calcification (4.78, 10, 15, and 20% crushed CaCO3) with phosphorus (P) sources [single superphosphate (SSP), rock phosphate (RP), farm yard manure (FYM), and poultry manure (PM)] in experiment 1 and with various rates of PM (4, 8, and 12 kg ha-1) in experiment 2 on cumulative soil respiration. These experiments were arranged in three factorial, complete randomize design (CRD) with three replications. Interactively, lime with P sources (at day 1 and 3) and lime with PSB (at day 1) significantly expedited soil respiration. Mainly, PSB inoculation, liming, PM fertilization, and its various rates significantly enhanced soil respiration with time over control/minimum in alkaline soil at all incubation periods. Higher CO2 emission was detected in soil supplemented with organic P sources (PM and FYM) than mineral sources (SSP and RP). CO2 emission was noted to increase with increasing PM content. Since liming intensified CO2 discharge from soil, therefore addition of lime to an alkaline soil should be avoided; instead, integrated approaches must be adopted for P management in alkaline calcareous soils for climate-smart agriculture.