Investigating a microbial approach to water conservation: Effects of Bacillus subtilis and Surfactin on evaporation dynamics in loam and sandy loam soils

Semi-arid regions faced with increasingly scarce freshwater resources must manage competing demands in the food-energy-water nexus. A possible solution modifies soil hydrologic properties using biosurfactants to reduce evaporation and improve water retention. In this study, two different textures representative of agricultural soils Kansas were treated a direct application biosurfactant, Surfactin, an indirect via inoculation Bacillus subtilis . Evaporation rates wetted measured when exposed artificial sunlight (1000 W/m 2 ) compared non-treated control soils. Experimental results indicate that both treatments alter moisture dynamics by increasing is plentiful (i.e., constant rate period) decreasing slower period). Furthermore, significantly reduced content at which transitioned from evaporation. Out treatments, B. generally produced greater changes dynamics; for example, treatment sandy loam increased periods 43% decreased 49%. comparing textures, exhibited larger effect than soil. To evaluate potential significance effects, System Dynamics Model operationalized simulated under typical daily precipitation conditions. The model methods altered probability exhibiting relative Overall, these findings suggest decrease threshold observed experimental setting could increase availability prolonging stage As had most pronounced effects contexts, future work should focus on testing field trials similar textures.