Improvability of quality main indices of a marl soil using endemic microorganisms

Biological soil crusts are essential for ecosystem productivity in arid and semiarid regions, where cyanobacteria (Cy) and bacteria (Ba) are pivotal. These microorganisms enhance nutritional conditions, soil stability, soil fertility, and forage quality through the secretion of polysaccharides. However, there is a lack of comprehensive quantitative studies addressing the changes in soil's physical and chemical properties. This research investigated the impact of individual and combined inoculations of Cy and Ba on the rangeland quality of low-quality soil in the Marzanabad region. The indicators of soil quality assessed included carbon (C) content, nitrogen (N) levels, C/N ratio, soil-available phosphorus (P), and aggregate stability. The findings indicated that microbial inoculation significantly (p < 0.01) affected N concentration, available P, and aggregate stability. Additionally, the individual and combined treatments of Cy and Ba resulted in increases in C content of 57.14%, 297.14%, and 120%, respectively, compared to the control. The N concentration in these treatments was 150%, 37.50%, and 325% higher than that of the control soil. In terms of absorbable P, increases of 105.48%, 6.54%, and 39.57% were observed compared to the control conditions. Furthermore, the superficial inoculation of microorganisms enhanced aggregation adhesion, with stability in the individual and combined Cy and Ba treatments increasing by 29.20%, 61.65%, and 42.11%, respectively, relative to the control treatment. The results of this study suggest that utilizing soil microorganisms to restore plant cover in arid and semiarid regions is a viable strategy.