Agricultural Field Plastics

The agriculture industry uses plastics to extend growing seasons, use resources efficiently, reduce water usage, save on labor costs, increase crop yield and quality, and cut down on agrichemicals. However, plastics can also pose an environmental threat. Wind and drainage areas can transport plastics, resulting in the accumulation of microplastics in watersheds draining to Monterey Bay National Marine Sanctuary.

Monterey Bay National Marine Sanctuary, in partnership with the California Marine Sanctuary Foundation, took an in depth look at the potential for plastic debris to enter the marine environment from agricultural areas. A 2019 assessment of agricultural field plastic use in Monterey County (one of the leading agricultural counties in California adjacent to Monterey Bay National Marine Sanctuary) estimated that 20,732,384 pounds per year of plastic is currently used on fields:

• Drip tape (12,191,672 pounds per year)
• Polyethylene mulch film and totally impermeable film used in fumigation (7,941,839 pounds per year)
• Hoop house plastic (598,874 pounds per year)

Due to the growing reliance of plastic in agriculture operations, staff engage with key stakeholders in several targeted efforts to implement end of life solutions, including strategies to give growers an appropriate outlet and prevent agriculture field plastics from entering the sanctuary. A number of projects are underway:

Soil-Biodegradable Plastic Mulch Film Trails

Strawberry and melon growers, among others, rely on plastic mulch films to provide weed management control and enhance productivity. In 2020, with funding from the U.S. Department of Agriculture, the California Marine Sanctuary Foundation and Monterey Bay National Marine Sanctuary, in collaboration with key partners, began doing small-scale trials of soil-biodegradable mulch (BDM), a viable replacement for traditional plastic mulch. BDM’s are designed to biodegrade in the soil by 90% within two years. Staff began in depth trials of BDM to advance understanding of the new technology and are currently continuing the trials of BDM’s in commercial fields.

Commercially Scalable End-of-Life Solutions for Agricultural Field Plastic

Each year about over 13,000 acres of strawberries are planted in Monterey and Santa Cruz county, lined with plastic mulch films. With the help of over $2.7 million in funding from the NOAA-National Sea Grant Infrastructure Investment and Jobs Act Marine Debris Challenge Competition, the project has allowed for California Sea Grant, California Marine Sanctuary Foundation, and industry partners (Flipping Iron Inc., Andros Engineering, and various berry growers) to improve the ability to remove and recycle this type of agricultural plastic mulch films, thereby significantly reducing amounts that reach nearby waterways. The project aims to refine technology and develop best practices that will increase the efficiency and suitability of agricultural plastics for recycling, and then extend these plastic end-of-life solutions to large and small scale growers. This project establishes a collaborative effort to transform growing techniques and processes that work with industry to prevent marine debris from entering Monterey Bay, Channel Islands, and Chumash Heritage national marine sanctuaries.

Drip Tape and Hoop Film Recycling

Full circle recycling programs are available for local stakeholders to mechanically recycle used drip irrigation tape. For growers unable to meet the requirements of the manufacture led recycling program, the California Marine Sanctuary Foundation and Monterey Bay National Marine Sanctuary, in collaboration with ReGen Monterey and Flipping Iron Inc., created a pilot program for recycling drip tape and hoop house film. With funding from the NOAA-National Sea Grant Infrastructure Investment and Jobs Act Marine Debris Challenge Competition, the program provides a collection point for agricultural plastics used locally. Growers, nurseries, and other agricultural field plastic users can dispose of used drip tape and hoop house films at ReGen Monterey.