Phosphorous (P)-Solubilizing Rhizobacteria Improve P Availability to Mung Bean via Enhanced Soil Phosphatase Activity and Improve Its Growth

Phosphorous (P) is an important macronutrient for plant growth and often acts as a limiting nutrient. It is mostly provided to plants by inorganic resources, most of which cannot be utilized by plants either due to precipitation or immobilization. Phosphate-solubilizing bacteria (PSB) can improve P availability by dissolving inorganic and mineralizing organic P in soil, and their activities in soil can be stimulated by different organic sources. We conducted a pot trial to check the efficacy of PSB, individually and in combination with different organic amendments for improving growth and yield of mung bean. Seeds were inoculated with PSB strain Psychrobacter sp. along with soil supplementation of various amendments (farmyard manure, poultry manure, press mud and biogas slurry at 2% w/w each). Co-application of PSB and organic amendments proved to be more beneficial than their individual application. Maximum improvements in plant attributes, i.e., plant height (66%), root length (52%), number of nodules plant-1 (129%), root area (101%), pods dry biomass (89%), SPAD value (41%), carotenoid contents (58%), and NPK contents in roots (139, 380, and 132%) and grains (41, 89, and 266%) were observed in combined application of PSB and poultry manure. Furthermore, combined application improved soil biological health in terms of phosphatase activity, and among them, maximum acid and alkaline phosphatase activities were enhanced by 53 and 68%, respectively, under co-application of PSB and poultry manure. Hence, integration of PSB with different organic amendments can significantly improve P availability to plants, and can improve its growth.

Automated summary

Phosphorous (P) is an important macronutrient for plant growth. Phosphate-solubilizing bacteria (PSB) can improve P availability in soil. The co-application of PSB with organic amendments, such as poultry manure, proved to be more beneficial for improving plant growth and yield.