Runoff suppression in freezing-thawing soils: The pivotal role of endemic bacterial inoculation

Abstract

Soil and water loss, especially during freezing and thawing, is a major global issue, and bacteria, can serve as a practical biological approach to conserve soil and water resources. This study was designed to investigate the effects of endemic bacteria application on controlling runoff under freezing-thawing cycle conditions. Soil from the Badranlou Region in Iran was collected and transferred to small erosion plots. The most suitable endemic bacteria, identified from a soil microbank for soil and water conservation, were isolated, purified, proliferated, and inoculated onto the plots in six replicates with a 20% slope at the laboratory. Treatments—bacterial inoculation versus non-inoculation—were tested under a simulated single freezing–thawing cycle and 30 minute rainfall at about 70 mm h-¹. Results showed that, compared to the control, inoculation significantly reduced surface runoff volume and the runoff coefficient. After 60 days, inoculation increased the time to runoff by 102%, reduced runoff volume by 33%, extended the time to peak by 18%, and decreased the peak time by 83% (p<0.001). This supports bacterial inoculation as an effective method for controlling water loss. In conclusion, soil bacteria have high potential to improve runoff characteristics and reduce surface erosion in cold, mountainous regions.