U.S. farms are covered in plastic, from the sides of greenhouses to plastic mulch, hoop houses, irrigation tubes, and more. As it degrades, plastic accumulates in soil and in plants, with potential threats to food safety.
Photo: Rows of plastic-covered strawberry plants.
In 1948, E.M. Emmert, a horticulturist at the University of Kentucky, was tinkering around with how to build a cheap greenhouse. He decided to use polyethylene sheets in lieu of the glass sides, bending the plastic film around a wooden frame. The plants thrived in the new environment; the plastic let in enough light while trapping in warmth.
This is commonly regarded as the first introduction of plastic into agriculture, a move that would transform modern farming—and inadvertently deposit an untold amount of plastic in the soil.
“There are currently no viable remediation techniques,” said Cusworth. “If you want to remove them from the soil, [the solution] is to stop producing them in the first place.”
—Samuel Cusworth
In the decades that followed, this cheap, pliant material spread through farms across the U.S. and world, becoming so widely used that plastics in agriculture gained its own name: plasticulture.
Today, it’s common to see farms covered in plastic. It lines the sides of greenhouses, blankets fields as “plastic mulch,” covers hoop houses, and winds through farms as irrigation tubes, among other forms. In satellite images, the National Aeronautics and Space Administration (NASA) has observed the typically golden and green agricultural fields turned white, as though dusted in snow, from all of the plastic.
Agriculture is responsible for 3.5 percent of global plastic production, a figure that may seem small until you consider the sheer volume of plastics produced: around 400 million metric tons per year.
Little did Emmert know that this plastic was also degrading over time, breaking down into tiny flakes and accumulating in the soil. Microplastics pervade every part of the Earth, from the bottom of the ocean floor to all forms of drinking water to the human placenta. Complicating matters, plastic doesn’t decompose; instead, it turns into smaller and smaller bits of plastic, eventually becoming invisible nanoplastics. A recent paper called the enormity of tiny plastic litter a “menace to the biosphere.”
“Everything that we create as humans degrades to some degree over time. That’s the reason we’re facing such a massive issue.”
“Everything that we create as humans degrades to some degree over time. That’s the reason we’re facing such a massive issue,” said Samuel Cusworth, a recent PhD graduate from the University of Lancaster in England, who focuses on microplastics in the soil. “And once they’re in the environment, they’re very hard to retrieve.”
The Earth’s soils have become a waste bin of the world’s plastics. Soil is thought to be even more polluted with microplastics than the ocean, which contains an estimated 358 trillion plastic particles. Agricultural soils have been called a “reservoir” for not just the plastic produced on farms, but also plastics from other industrial sources that enter the water to eventually wash up on farms during a flood, or are carried by the wind. In a world where all industries run on plastics, these fine particles can also find their way onto farms through poultry litter, sewage sludge applied to soils, and even fertilizer.
“There are currently no viable remediation techniques,” said Cusworth. “If you want to remove them from the soil, [the solution] is to stop producing them in the first place.”
The major producers of plastics, like ExxonMobil and Dow, continue to sell plastic to farmers as a way to adapt to […]
Full article: civileats.com