Symbiosis with plants by mycorrhiza and rhizobium (bio-fertilizers) is effective in improving soil structure and increasing the stability of aggregates against compression. In addition to soil deformation, soil structural properties should be included for the assessment of compaction. The purpose of this study was to investigate the effect of application of rhizobium and mycorrhizae on plant yield, some soil physical properties, and the confined compression curve and its characteristics, which have not been reported in any research so far. Experiments were conducted in a completely randomized design with three replications in the field and glasshouse. Mycorrhizal fungi (Funneliformis mosseae), rhizobium (Mesorhizobium), mycorrhiza - rhizobium and control (no inoculation) were the treatments of the field experiment. Sterilized mycorrhiza background material and non-plant-non-inoculation were the two additional treatments of the glasshouse experiment. The plant cultivated in this experiment was chickpea. Mycorrhizal and rhizobium treatments increased the stability of aggregates compared to non-plant-non-inoculation treatment. Mycorrhiza and rhizobium increased the macroporosity and near-saturation water content. The smallest total yield was found in the sterilized mycorrhiza background material and control treatments. Mycorrhiza and rhizobium increased the void ratio at different compression stresses by 9-16% and 19-25%, respectively, compared to non-inoculation treatments under the glasshouse experiment. Pre-compression stress was increased by 84.3% in the control treatment with plant compared to the mycorrhiza treatment in the glasshouse experiment, but did not change significantly in the field experiment. Symbiosis of mycorrhiza and rhizobium as a sustainable biological method improved the physical and mechanical properties of the soil by affecting plant yield and root exudates.
