Biodegradable Mulches and Specialty Crop Production

The use of plastic mulch for the production of vegetable crops in the U.S. has doubled in the last 10 years. While energy costs have risen dramatically in the last 5 years, plastic film manufacturers have saved money on the production of mulch film by reducing the thickness of the film; film thickness has gradually gone from 1.5 mil. to 0.5–0.7 mil. during this time period. One disadvantage of the thin plastic film is the retrieval potential for growers after the crop has been harvested in the field. Thin films 0.7 mil. or less do not retrieve from the field very easily and thus are more difficult to remove for recycling or disposal. Plastic mulch films that are biodegradable have been developed, and are being sold commercially in Europe and North America. These new, innovative plastic films biodegrade during composting, and are being evaluated for biodegradability in the field. They can also be rototilled into the soil at the end of the growing season, saving at least $100/A for pick up and disposal. Field research has demonstrated that the biodegradable mulches will produce equivalent marketable yields of most specialty horticultural crops compared to standard plastic mulch. Warm season vegetable crops have performed very well when grown on biodegradable plastic mulch. Two issues that growers may be apprehensive about are the initial cost of the biodegradable mulch compared to standard plastic mulch, and the sometimes unpredictable degradation rate and timing of biodegradable mulch. This presentation will discuss the history of biodegradable mulches in the market place in the U.S., including early products and issues regarding their biodegradability in the field and in composting. Also discussed will be an overview of some current biodegradable mulches and their impact on yield of vegetable crops.