Session: 01-01-04 Fluid Machinery Symposium

Paper Number: 138569

138569 - The Potential of Surfactin in Agriculture to Reduce Irrigation Water Use: Reducing Water Need in Soil and the Effect in Spray Dynamics 

Irrigation is vital for agriculture and requires a large quantity of water. In Kansas, 83% of water use is for crop irrigation; a majority of which is drawn from the rapidly depleting Ogallala Aquifer. Using water effectively and maximizing its impact is imperative to reduce the strain on the aquifer. Surfactants have been studied in soil to alter wettability and soil water holding capacity. Surfactants have also been investigated in agriculture spray solutions to improve spray performance by stabilizing the spray sheet and altering droplet sizes. This work investigated the effect of Surfactin (a biosurfactant created by B. subtilis) and the bacteria B. subtilis on the evaporation rate of water from soil. The evaporation rate increased during the constant-rate period but decreased during the slower-rate period compared to soil without Surfactin or B. subtilis. The decrease in evaporation rate increased the length of time moisture is present in the soil; thereby, creating the potential for soil treated with Surfactin or B. subtilis to preserve soil moisture. Retaining water in the soil for longer periods of time can decrease the amount of required irrigation water; however, it is important to also consider the mechanisms for applying Surfactin. This work additionally investigated the addition of Surfactin to distilled water on spray dynamics in flat fan, cone, and bubbler nozzles. In the flat fan and cone nozzles, the Surfactin increased the breakup length and decreased the volumetric mean diameter of the resulting droplets compared to pure distilled water. In the bubbler nozzle, the Surfactin increased the breakup length as well as the droplet size. Changing the spray dynamics impacts the potential for drift as well as the distribution of the solution within the soil.

Presenting Author: Emily Stallbaumer-Cyr Kansas State University