Weed Control Efficacy of Bio-Based Sprayable Mulch Films in Specialty Crop Systems

A sprayable bio-based mulch film (biofilm) could present a more sustainable weed management tool for specialty crop producers than conventional plastic mulch films while also offering flexibility in application patterns and timing. From 2017 to 2019, six greenhouse trials and four field trials were conducted at the University of Nebraska-Lincoln to study the effects of biofilm application on weed suppression and crop yields. Multiple application rates (0.81 L/m2 - 9.78 L/m2) and application times (prior to weed emergence and post weed emergence) were tested. Corn starch, glycerol, keratin hydrolysate, corn gluten meal, corn zein, and isolated soy protein were evaluated as potential ingredients due to their ability to form biodegradable films or suppress weed growth as reported in other research. The efficacy of weed control displayed by biofilm solutions ranged from a promotion of weed biomass to 100% reductions relative to a non-treated, weedy control. The wide range of results was most likely attributable to solution viscosity: a greater efficacy of weed control was displayed when the viscosity was increased as this allowed a more cohesive layer to form on the soil surface. The most promising mulch film was displayed in the final field trial, to which biomass was reduced by greater than 97% when applied prior to weed emergence and by greater than 94% when applied post weed emergence. However, despite these findings, crop yields were not improved relative to a non-treated, weedy control in any of the field trials. Variables such as solution salinity and C:N ratio could play a role and need to be evaluated in future research trials. Advisors: Sam Wortman and Sibel Irma