The potential of soil endemic microorganisms in ameliorating the physicochemical properties of soil subjected to a freeze-thaw cycle

Establishing soil biological crusts will result in the long-term restoration of ecosystems. Nonetheless, little research has been conducted to demonstrate the influence of soil endemic microorganisms on suppressing the adverse effects of freezing-thawing on soil properties. This current study evaluated the formation of biological crusts, the enhancement of physical and chemical characteristics of soil, and surface soil stability by inoculating native bacteria and cyanobacteria into the soil during a freezing-thawing cycle. The soil was collected from the Badranlou Region in North Khorasan Province, Northern Iran, and native bacteria and cyanobacteria were isolated, identified, chosen, and cultured. The native treatments of bacteria and cyanobacteria were then inoculated in individual bacteria, cyanobacteria, and combined inoculation of cyanobacteria and bacteria onto an experimental soil in six replications. After 60 days, they were subjected to freezing-thawing conditions to have maximum effect on the soil environment, and finally, the soil surface properties were statistically compared. The results of the significant effect (p<0.001) of inoculation treatments on the physical and chemical properties of the study soil revealed that the carbon, nitrogen, organic matter, phosphorus, potassium, and surface soil stability in bacterial treatment compared to the control treatment increased by 68, 39, 68, 17, 25, 99 %, respectively. While under cyanobacterial treatment, they rose by 83, 61, 83, 18, 73, and 172 %, respectively. The combination inoculation treatment of bacteria and cyanobacteria enhanced the study variables by 73, 66, 73, 25, 58, and 189 %, respectively. Compared to control plots, the soil bulk density in bacterial, cyanobacterial, and compound inoculation treatments was substantially reduced (p<0.001) by 9, 15, and 12 %, respectively. The soil stability, carbon, and organic matter were among the most essential properties of the soil, and they best showed the difference between the various treatments applied. It confirmed the region's potential restoration by inoculating native soil microorganisms.