News and commentary about the American food system.
While the plastics used at every step of the farming process can boost productivity, they also pollute the soil and the food we eat. New research has farmers and advocates pushing for change. Flexible Printing
Plastics are tightly woven into the fabric of modern agriculture. Black polyethylene “mulch film” gets tucked snugly around crop rows, clear plastic sheeting covers hoop houses, and most farmers use plastic seed trays, irrigation tubes, and fertilizer bags.
These synthetic polymer products have often been used to help boost yields up to 60 percent and make water and pesticide use more efficient. In China, for example, research shows that plastic field covers keep the soil warm and wet in a way that boosts productivity considerably; an additional 15,000 square miles of arable land—an area about the size of Switzerland—would be required to produce the same amount of food.
Research shows that as the chemicals from degrading debris leach into the soil, their persistence decreases crop productivity while snaking up the food chain, appearing in earthworm guts and even human placentas.
But plasticulture, or the use of plastic products in agriculture, also comes with a wide range of known problems. Plastic contaminates fields at a much greater scale than it does our oceans, posing an acute threat to soil health and food security. Research shows that as the chemicals from degrading debris leach into the soil, their persistence decreases crop productivity while snaking up the food chain, appearing in earthworm guts and even human placentas.
In the larger scope, agriculture accounts for a small slice of the plastics pie—less than 3 percent of the annual 440 million tons produced worldwide. Yet their pervasive use—along with farmland, plastics cover everything from individual seeds to bales of hay and packaged produce—has allowed them to plant themselves deeply in our food supply. “Relatively speaking, it’s a small volume,” says Philip Demokritou, vice chair of Rutgers University’s environmental occupational health and justice department and author of a recent international report on plastics in agriculture. “But it carries the highest risks.”
Given the challenges of feeding a ballooning global population, curtailing our dependence on plastics to grow food is a daunting proposition. Simply put, “there are no magic solutions,” says Demokritou. Mitigation requires slashing production and consumption, he adds, and increasing recycling and reuse all along the supply chain.
From implementing policies, incentives, and regulations to engaging producers, farmers, and consumers, it’s an all-encompassing effort that “we need to battle collectively as a society,” he says. And yet considering the impacts to both environmental and human health, investing in comprehensive, innovative, and proactive measures will be far more cost-effective, Demokritou suggests, “than feeding disease and disasters down the line.”
The world has a voracious appetite for plastic. The Organization for Economic Cooperation and Development (OECD) estimates that global plastic waste is on track to nearly triple by 2060. With less than a fifth of the end stream getting recycled, single-use products make up the bulk of the waste, and it’s destined to go to landfills, be incinerated, or escape into the larger environment.
Meanwhile, 98 percent of disposables are made from “virgin” feedstock, driving renewed growth for fossil fuel companies that supply the raw material. All told, annual greenhouse gases released from plastic production, landfilling, and incineration total 850 million tons, or 4.5 percent of global emissions. And studies also show that plastic pollution disproportionately affects disadvantaged communities.
According to FAO, plastic films such as black mulch and greenhouse covers account for the bulk of annual global use, at more than 8 million tons.
Nevertheless, the versatility, affordability, and convenience of synthetic polymers make them indispensable to most industries, including agriculture. The field consumes 14 million tons of plastics every year, with crop and livestock production accounting for 80 percent.
In 2021, the United Nations (U.N.) Food and Agriculture Organization (FAO) issued a report highlighting the urgent need for more sustainable use of agricultural plastics. The landmark assessment subsequently paved the way for the U.N. to push for a global treaty to slash plastic pollution.
According to FAO, plastic films such as black mulch and greenhouse covers account for the bulk of annual global use, at more than 8 million tons. In addition to extending the growing season by warming the soil, safeguarding plants’ roots, and preserving soil moisture, these plastics also suppress weeds.
The drawbacks, however, are just as consequential. Plastic mulch creates an impervious surface that concentrates chemical runoff while overheating fields and impacting soil health. And the single-use product is neither recyclable nor reusable, requiring seasonal retrieval and disposal. The Rodale Institute, a nonprofit research institution for organic farming, cites that every acre of land farmed with plastic mulch creates upwards of 120 pounds of waste that typically end up in landfill, or otherwise break down into the soil or nearby watersheds.
In China, where farms use enough plastic film to cover the surface area of Idaho every year, the difficulty of end-of-season removal led growers, at one point, to plow the plastic directly into the field. The widespread practice, which took place through the late aughts, “had a deleterious effect on soil quality,” says Richard H. Thompson, a former agricultural plastics sustainability expert at FAO and a lead author of the 2021 report. As contamination rose, crop yields fell by 15 percent.
That practice was banned, but plastics have continued to disintegrate and leave an unavoidable trail of debris and impacts—wherever they’re used. “It takes about 10,000 chemicals to produce plastics,” says Rutgers’ Demokritou, noting that the additives are necessary to give polymers flexibility and other functionality.
As they fragment under sunlight, temperature fluctuations, and wear and tear, the micro- and nanoplastic (MNP) particles remain chemically stable even as they physically decompose. Accumulating in soils over time, the residues hinder water absorption and impact microbial communities. Eventually, MNPs “pollute the food chain,” Demokritou says, posing health risks such as disrupting endocrine and digestive functions and harboring drug-resistant superbugs.
In the past decade, the massive reliance on plastic mulch has spurred the development of greener alternatives employable on an equivalent scale. Several agrochemical companies have developed biodegradable plastic mulches (BDMs) that, while doubly expensive, relieve farmers of the cost and labor of removal by decomposing into the soil.
Yet independent studies on their long-term impacts to both soil health and crop productivity remain inconclusive. To give them the requisite plasticity, BDMs contain many similar additives as those found in conventional films, says Thompson, “so the jury is still out.”
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The U.S. Department of Agriculture’s (USDA) National Organic Program (NOP) regulations require organic growers to use BDMs made with no less than 80 percent bio-based sources. Currently organic farms are permitted to use petroleum-based, non-PVC covers, granted that they are removed from the field at season’s end. However, no biodegradable films meet the NOP’s minimum threshold. (The European Union‘s organic farming regulations, however, permit bio-based, biodegradable films.)
While regulations can help drive innovation, driving coordinated action requires the development of an international framework that outlines sustainable use and management practices, says Thompson. By setting legally binding targets along the lines of the 2015 Paris Climate Agreement, the proposed U.N. treaty will be a groundbreaking effort to address plastic waste.
But achieving universal consensus is never easy, he says, so a voluntary code of conduct—a blueprint of sorts that outlines best practices and establishes responsibility for “all the different actors in the plastic supply chain”—would be much more effective in directing country-specific policies and legislation.
The U.S., for its part, has dragged its feet on endorsing a binding U.N. treaty, despite being the world’s largest generator of plastic waste. National efforts to stem the tide have also largely stalled. The latest federal bill, the Break Free From Plastic Pollution Act of 2023—the dead-on-arrival proposal was the third of its kind introduced in Congress in the last four years—called for a ban on certain single-use products and more end-of-life responsibility for producers.
“Without binding agreements, these programs fail when they begin to threaten [the] bottom line.”
A few states have made strides in directing the onus of waste management onto the industry itself. Maine, Oregon, and Colorado have approved extended producer responsibility (EPR) programs, which require packaging producers to shoulder the costs of recycling their products. And California recently passed the Plastic Pollution Producer Responsibility Act. The comprehensive law, which includes EPR provisions that go into effect in 2027, is intended to decrease single-use plastics and packaging, support communities vulnerable to plastic pollution, and promote a path toward a circular economy.
“Mandatory EPR policies are a powerful tool for transparency and accountability in an industry that is currently anything but,” says Anja Brandon, Ocean Conservancy’s associate director of U.S. plastics policy.
Industry-supported programs such as the Ag Container Recycling Council (ACRC)—the 30-year-old, not-for-profit trade association that collects pesticide drums and containers for recycling into landscaping pavers, drainpipe, and other end products—are voluntary. Yet producer-set goals and targets lack financial accountability for end-of-life product management, Brandon says. “Without binding agreements, these programs fail when they begin to threaten [the] bottom line.”
Currently, none of the EPR laws on the books specifically address agricultural plastics, focusing instead on reducing single-use packaging and food containers. California has required pesticide containers of a certain size to be recycled since 2009, though with no deposit or tracking system for returning containers in place, the estimated recycling rate runs about 50 percent, according to a spokesperson for the California Department of Pesticide Regulation, which runs the program
Creating transformational change and investment in the circular economy require policies that extend across the industry, Brandon adds. And along with redesigning plastics to “actually be recyclable,” improved reuse and recycling processes and investment in cleanups are crucial to meeting those goals, she says.
Still, the broad impacts of agricultural plastics create an inherent opportunity to engage a diverse range of players. A 2019 study by the California Marine Sanctuary Foundation (CMSF) shows the extensive reach of farm-generated debris, particularly along watersheds adjacent to agricultural hotspots. Researchers found the state’s coastline along the Monterey Bay National Marine Sanctuary (MBNMS)—the country’s largest federally protected marine area—littered with mulch and film, as well as irrigation tape, tubing, and hoses that had escaped from nearby fields in the farm-rich region.
The findings also revealed an array of stakeholders, who have since worked in tandem to develop effective waste management strategies. The Monterey County-based effort has created “strong collaboration all across the supply chain,” says Jazmine Mejia-Muñoz, CMSF’s water quality program manager, one that has prompted similar efforts further down the California coast.
By enlisting stakeholders—from small to large-scale growers, product manufacturers, and service providers that provide on-farm plastics collection and retrieval—through awareness and incentivized action, the regional waste management district has vastly increased the collection and recycling of drip tape and plastic film, says Mejia-Muñoz. (Growers get discounted dumping fees for cleaning, separating, and bundling products, all of which streamline the recycling process.)
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The work is also supported by the MBNMS and the Agriculture Water Quality Alliance, a partnership of agriculture industry groups, resource conservation agencies, researchers, and environmental organizations stewarding Monterey Bay. CMSF has also partnered with the USDA and academic institutions in trialing biodegradable and recyclable films, helping to create a feedback loop between farmers, manufacturers and soil scientists on field-specific needs and performance. “It’s definitely a big team, but every member is so critical,” Mejia-Muñoz says.
But despite these efforts, tackling the scourge of plastics will still take large efforts to wean our dependence on disposables. “We need to mandate a reduction in plastic production across the board,” says Ocean Conservatory’s Brandon, “starting with single-use plastics.”
“We cannot continue to throw chemicals and materials out there . . . and clean up the mess 20, 30, 40 years later.”
For agriculture, bio-based alternatives to its biggest offender may not, in fact, require extensive innovation. Instead of film, many small farms employing sustainable and regenerative practices use natural mulches such as wood chips, leaves, or straw, relying on the low-cost, time-honored practice to keep weeds in check and regulate soil moisture and temperature. And while kraft paper has fallen short of matching the yields and durability of plastic mulch, a recently trialed version promises an uncoated and industrially compostable product that, according to the manufacturer, “provides a comparable level of protection.”
The Rodale Institute has also studied cover crops as a viable solution: Mowing or rolling vetch or rye grass into a solid mat has “great potential to replace plastic mulch,” says Vegetable Systems Trial Director Gladys Zinati. Though crop type, growing region, and the existing weed bank—the level of invasive seeds present in the soil—all impact effectiveness, her research showed that a solid mat of crimped vetch or rye grass resulted in greater crop yields with lower implementation costs than plastic sheets. (Soil moisture also increased, though minimally, and not enough to replace irrigation.)
While the trials were limited to farms less than 80 acres in size, Zinati sees major promise in expanding the practice. “Depending on [those] factors,” she adds,” everything is scalable.” (Rodale has even designed an add-on device for tractors, making the blueprint publicly available.)
Ultimately, history has repeatedly shown that the cycle of plastic pollution “is not a sustainable model,” says Rutgers’ Demokritou. “We cannot continue to throw chemicals and materials out there . . . and clean up the mess 20, 30, 40 years later.” And as much as our widespread reliance on plastics may seem inseverable, transformative change, he adds, is possible.
“Look what happened to asbestos,” Demokritou says. “That industry [all but] disappeared, right?”
Naoki Nitta is a freelance writer based in Northern California, focused on food and sustainability issues. His work has appeared in Modern Farmer, Grist, Smithsonian Magazine, San Francisco Chronicle, and other publications. Read more >
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