Sprayable starch films as mulching for organic agriculture

Abstract

In accordance with the sustainable agricultural concepts, the pursuit of eco-conscious solutions has driven research into the development of biodegradable materials for mulching applications as a response to environmental challenges. In this study, biodegradable sprayable films were produced from thermally gelatinized cassava starch suspensions (5% w/v) to explore their potential application as protective coatings for agricultural soils. The starch gelatinization process was optimized to evaluate the feasibility to be applied by the spraying technique. Results showed that it is necessary to carry out a previous dilution of the gelatinized suspensions (1:4) to be able to spray them and form a uniform layer on the soil. To enhance film properties, bentonite clay (0, 5, and 10 wt% starch basis) was introduced as reinforcement and sodium tetraborate (0 and 3 wt% starch basis) as a crosslinking agent. By SEM, a uniform bentonite particle distribution within the starch matrix was observed, and the presence of the highest clay concentration increased the capacity to block UV radiation 8.7 times, while PAR coefficient (photosynthetically active radiation) was reduced up to 30%. Tensile and puncture tests revealed that bentonite and borax presence doubled the final film’s resistance, and its biodegradability was confirmed through water solubility and composting tests. Finally, the application of the sprayable starch films as agronomic mulching did not affect the normal growth of pepper plants. The comprehensive findings from this study provide crucial insights into the implementation of eco-conscious innovations in crop cultivation and soil management techniques.