James Schrader, Gowrishanker Srinivasan, David Grewell, and William Graves
Iowa State University
An important obstacle to sustainability in the container-crops industry is the nearly universal reliance on containers made from non-renewable, petroleum-based plastics. As part of a project to develop and assess biodegradable plastics for their potential to replace petroleum-based plastics in specialty-crop containers, we evaluated prototype plastic containers made from soy (Glycine) protein for their effectiveness during production of tomato and pepper in greenhouses and subsequent establishment of those plants outdoors. The fertilizer effect provided by soy-protein prototype containers during greenhouse production was excessive and caused plants to be smaller and less healthy than control plants. In the garden trial that followed, the fertilizer effect provided during biodegradation of soy pots in the soil near plant roots was beneficial for plant growth and health, and the rate of biodegradation in garden soil appeared to be nearly optimal for utilizing the fertilizer effect.