To boost food production, China has spread polyethylene film across 49 million acres — 12 percent of the country’s total farmland — despite warnings that the synthetic mulch is toxic and degrades the soil.
Polypropylene film can increase yields by 30 percent by trapping moisture and heat and keeping pests and weeds out. But it “isn’t biodegradable and often not recycled,” says Bloomberg. “Potentially cancer-causing toxins can be released into the soil from the plastic residue, known locally as ‘white pollution,’ which is present at levels of 60 to 300 kilograms (132 to 661 pounds) per hectare in some provinces.”
As polypropylene film breaks down, it can also damage soil structure, harm earthworms if it’s ingested, and, according to some sources, hamper plant growth in the long run. A fifth of China’s arable land already shows toxin levels higher than national standards. But farmers aren’t swayed by biodegradable options, which don’t hold heat or moisture as well as plastic and are more expensive.