Interaction study of biochar with phosphate-solubilizing bacterium on phosphorus availability in calcareous soil

A large proportion of phosphate fertilizer applied to calcareous soils reacts with calcium. Changes in soil phosphorus (P) availability after single application of biochar and phosphate-solubilizing bacteria have been reported. However, interaction of biochar (increasing soil pH) and phosphate-solubilizing bacteria (decreasing soil pH) on P availability in calcareous soil is not well known. An incubation experiment was conducted to study how the interactive effects of biochars (produced from wheat straw and cow manure at 300 degrees C and 500 degrees C with residence time of 1, 3 and 6h) at different rates (0, 5 and 10t ha(-1)) and phosphate-solubilizing Pseudomonas sp. IS8b2 affected on content of soil available P after 0, 60, 120 and 180days of incubation (DOI) in a calcareous soil. After 60 DOI, the maximum value of available P (50.31mgkg(-1)) was observed in the compound treatment of Pseudomonas sp. IS8b2 and wheat straw biochar (10 t ha(-1)) produced at 500 degrees C with residence time of 3h. We conclude that the combination use of wheat straw biochar and phosphate-solubilizing bacterium is promising to potentially improve soil P availability in calcareous soil, but further research at field scale is needed to confirm this.