Improvability of Water Infiltration in an Erosion-Prone Soils under Laboratorial Conditions through Artificial Increasing of Soil Microorganisms Population

Runoff production process is a key hydrological component illustrating watersheds health. Water infiltration in soil is also one of the determinant factors on runoff generation for which many techniques were used to improve it. However, the role of microorganisms for the improvement of water infiltration in soil has been less considered. The present study therefore tried to investigate the effect of artificial soil bacteria population proliferation as a completely biologically and modern technique to improve soil surface properties and increase soil infiltration. To this end, the beneficial bacteria include Bacillus subtilis strain and Azotobacter sp. were isolated and inoculated individually and combined with B4 stimulant nutrient matter to small erosion plots filled by an erosion-prone soil of Marzanabad-Kandelus road neighboring region and left for 60 days. The water infiltration in soil was then measured after rainfall simulation in experimental condition and then the statistical analyses were conducted. The results showed that the inoculation treatments (individually inoculation of Bacillus subtilis strain and Azotobacter sp., individually injection of B4 stimulant nutrient matter and combined inoculation of bacteria and B4 stimulant nutrient matter) improved the water infiltration in soil and reduced volume and consequently coefficient of runoff in 99% of confidence level compared to control. The water infiltration in soil in Bacillus subtilis strain and Azotobacter sp. bacteria inoculation, B4 stimulant nutrient matter and their combined treatments increased about 18, 10 and 21%, respectively. In conclusion, enrichment of soil crust bacteria population through inoculation and simulation techniques was approved in reducing runoff yield. The combined inoculation of Bacillus subtilis strain and Azotobacter sp. bacteria with B4 stimulant nutrient matter had the best performance in increasing water infiltration in study soil.