| چکیده انگلیسی مقاله |
Extreme climatic characteristics including freezing-thawing cycle affect soil erosion processes and facilitate exaggerated damages to natural-human coupled ecosystems. Further efficient and comprehensive efforts are therefore required to turn towards sustainable development. This involves alternative approaches by focusing on the protection of natural resources and ecosystems, leading to soil and water conservation and economic profitability. Recent studies have focused on natural based approaches among which the formation of soil biological crusts through inoculation of bacteria and cyanobacteria for soil stabilization can be exemplified. However, modification of hydrologic behaviours of the soil due to inoculation of endemic microorganisms has received less attention. The present study was accordingly designed to determine the role of inoculation of native bacteria and cyanobacteria on the inhibition of surface runoff under physical simulation of a freezing-thawing cycle at the laboratorial scale. In this regards, the study soil was primarily collected from the dry land of Badranlou Area in North Khorasan Province and transferred to the small erosion plots (0.5 × 0.5 m) with constant slope of 20% placed in the Rain and Erosion Simulation Laboratory of Tarbiat Modares University, Iran. The dominant and non-pathogenic bacteria and cyanobacteria and available in the micro-bank of study soil were identified, selected, purificated and proliferated. The selected bacteria and cyanobacteria were then inoculated to the study soil before subjecting to a freezing-thawing cycle in six replications. The treated and control plots were ultimately subjected to a simulated study rain with intensity of about 70 mm.h-1 lasted for 30 min whose hydrologic outputs were compared. Comparison of the control and inoculated treatments with individual and combined inoculation of bacteria and cyanobacteria under a freezing and thawing cycle in 60 days after inoculation showed significant (p<0.001) improvement in the surface runoff components. So that, bacteria, cyanobacteria and the combined treatments increased the start time by 102, 228 and 266% and time to peak by 26, 49 and 56%; whilst they decreased the runoff peak by 22, 48 and 55% and runoff volume by 33, 65 and 73%, respectively. The results of the present study disclosed that soil microorganism inoculation including bacteria and cyanobacteria is an efficient, an economic and a bio-sustainable tool for improving runoff components in areas influenced by freezing-thawing phenomena. |
