Turfgrass production and maintenance relies heavily on the addition of nutrients, typically in the form of synthetic fertilizers based on natural gas. Soy-based biocomposite fertilizers have the potential to replace these synthetic fertilizers and reduce dependence on abiotic resources as well as decrease the environmental impact associated with the production and use of synthetic fertilizers.

Plant-based turfgrass fertilizers already exist on the market and typically use plant materials, such as sugar beets, that are relatively difficult and costly to produce. Soybeans are the preferred plant protein to provide nutrients in a biocomposite fertilizer because of the soybean’s unique relationship with bacteria that allows it to utilize nitrogen gas from the atmosphere. Soybeans are also grown on a large scale in the Midwest, making them readily available.

In this work, it was determined that soy-based biocomposites performed as well as commercially available fertilizers in terms of facilitating plant growth. It was also seen that nutrient levels in leachate samples were not significantly different for soy-biocomposite fertilizers compared to synthetic slow-release fertilizers when applied at a standard application rate. Addition, when over-applied the soy-based composites exhibited drawbacks similar to that of some synthetic fertilizers.

Economic analysis demonstrated that soy-based biocomposites could be produced on a commercial scale and at a competitive cost. Dependent on the specific formulation, the production costs for soy biocomposites were as low as $15.15 per pound of nitrogen. In comparison, the synthetic slow-release fertilizers used for comparison in this study are currently sold at a retail price of $54.73 per pound of nitrogen.

A life cycle assessment also demonstrated that the cradle-to-gate production of soy-biocomposite fertilizers creates significantly less global warming potential (GWP) compared to the production of traditional ammonium nitrate and urea fertilizers. In the case of biocomposites comprising of more than 60% soy filler, the GWP was shown to be negative, suggesting the production of these biocomposites have the potential to sequester greenhouse gases.