Synergistic Effect of Rhizobia and Biochar on Growth and Physiology of Maize

This experiment aimed to evaluate plant growth promoting rhizobia in combination with biochar for improving the growth and physiology of maize (Zea mays L.). Three rhizobia isolated from different legumes (RH1, RH2, and RH3) were used to inoculate maize growing in soil amended with different levels of biochar (0.0, 0.5, 1.0, and 1.5%) under controlled conditions. The magnitude of improvement in the growth and physiology of maize varied due to rhizobial inoculation and application of biochar, either alone or in combination. Combined application of different rhizobia and biochar caused significant improvement in the growth and physiological attributes of maize over their sole use. The performance of all tested rhizobia was comparatively better at the 1.0% biochar level for improving maize growth compared with the other biochar levels (0.5 and 1.5%). Rhizobial strain RH1 showed the most prominent results for improving the growth of maize among all the tested rhizobia either used alone or in combination with biochar. Phosphatase, dehydrogenase, and microbial biomass C were also improved in the rhizosphere due to rhizobial inoculation and biochar. This work clearly indicates that the rhizobia from different legumes variably improved the growth and physiology of maize. However, the performance of rhizobia could be further improved when used in combination with an appropriate level of biochar.