Effects of Combined Application of Bradyrhizobium Japonicum and Pseudomonas Putida on Nutrients and Water Contents of Soybean in Relation to Soil Moisture Regime

Abstract Plant growth promoting rhizobacteria (PGPR) are of growing interest for their potential role in improving soil fertility and enhancing crops productivity and nutrients contents. In order to assess the impact of PGPR on nutrients contents of soybean, a greenhouse experiment was carried out with Bradyrhizobium japonicum applied alone or in combination with Pseudomonas putida in conjunction with fertilization of P or manure. Two soil moisture regimes were installed: 70% of whole holding capacity (WHC) as control and 35% WHC as moderate water stress. The water deficit was imposed at the flowering stage for 12 days. Plants cultivated under P insufficiency and drought exhibited lower physiological parameters in treatment with single inoculation of B. japonicum than combined application of two rhizobacteria. The results showed that the combined application of rhizobacteria enhanced the N and P contents of soybean regarding of soil water conditions. The integrated use of rhizobacteria improved the relative water content of soybean. Their influence was more pronounced under P deficiency and manure fertilization of plants especially under no stress water conditions. Hence, combined application of B. japonicum and P. putida has a potential to improve nutrition and growth of soybean under normal soil moisture as well as under moderate drought.