Impact of Pseudomonas putida on Available Soil Phosphorus Dynamics and Crop Productivity under Lowland Rice Ecology

The ability of phosphorus solubilizing bacteria (PSB) to solubilize soil phosphorus (P) in actual field condition is never beyond scientific contradiction. Further, its (PSB) dynamics under unique waterlogged, anaerobic rice ecosystem is a matter of interest. In this context, performance of Pseudomonas putida was tested as PSB in lowland rice soil. No significant impact of P. putida on soil available P status was found. The treatment of crop seedlings with PSB also showed no major response onto the vegetative as well as yield parameters of rice crop. Results inferred that, in presence of optimum amount of soil N and K, the addition of external P through phosphatic fertilizer and/or vermicompost was the controlling factor for soil P availability as well as productivity and quality of rice. Further, vermicompost boosted the soil total microbial population. The irrelevant impact of P. putida as PSB onto the soil available P status and rice productivity might be partially due to the anaerobic waterlogged rice environment, which did not support the proliferation and activity of these aerobic gram-negative bacteria. However, in comparison to the earlier findings, a further detailed study at field level is necessary to understand the dynamics of PSB in submerged rice soil.