Old McDonald Has a Plastic Mulch Dilemma
Green Acres is the place to be.
Farm livin' is the life for me.
Land spreadin' out so far and wide,
Keep Manhattan, just give me that countryside.
The face of farming has changed considerably since the Douglases (a/k/a Eddie Albert and Eva Gabor) left Manhattan behind to embrace a simple country life. Plastic has infiltrated agriculture in the same way that it has modern society.
There is a growing awareness and concern that plastic can be found everywhere in our daily lives – from the moment we wake up (shampoo and body wash in plastic bottles, plastic toothbrush and dental floss, plastic razor, synthetic clothing) to the food we eat during our busy day (plastic to-go cup, Styrofoam carryout container, plastic utensils, plastic straw), to our trip to the grocery store at the end of the day where everything seems to be packaged in plastic.
Of course, you may be one of the savvier shoppers and use refillable containers for your personal care items, bring your own to-go cup and carryout container, shop the bulk aisle at the grocery store for your beans and grains, and choose loose veggies in the produce aisle. So, it may surprise you to learn that most grains and veggies are no stranger to plastic. Using plastic to grow crops is common enough that it has its own name – plasticulture.
Sheets of thin plastic film are used to help minimize weeds and regulate soil temperature and moisture in fields. Since the concept was introduced in the 1950s when plastic production exploded at the end of World War II, the manufacture of plastic for agricultural purposes has grown to 3.5% of all the plastic produced annually with plastic mulch being the biggest contributor at 40%.
Plastic mulch is difficult to recycle because it becomes contaminated with dirt, fertilizer and pesticides. When plastic cannot be recycled, in some parts of the world it is burned releasing dioxin into the air or it is routinely landfilled. Plastic mulch is used in conventional and organic farming. Because it is a petroleum-based product and can result in up to 120 pounds per acre each year being landfilled, the Rodale Institute recognizes that even though black plastic mulch is “allowed within organic agriculture, it is inherently unsustainable.”
But plastic mulch poses more than just a disposal problem. Organic farming is focused on improving the health and biology of the soil, but removing the thin plastic film from the fields after the growing season leaves microplastics behind that can negatively alter the composition of the soil and harm the microorganisms and microbes that live there.
In experiments performed by Mary Beth Kirkham, a plant physiologist and professor of agronomy at Kansas State University, plants grown in soil containing microplastics performed poorly. “The particulate plastic appeared to clog the soil pores, prevent aeration of the soil, and cause. . . the roots to die,” said Kirkham.
Biodegradable plastic mulch is commercially available but it is not permitted in U.S. organic farming. Harriet Behar, chairwoman of the National Organic Standards Board (NOSB), which advises the U.S. Department of Agriculture on organic regulations, says, "We're looking at it (biodegradable plastic mulch) in a bigger way than just, ‘Is it biodegrading?’ We need to make sure that what we're putting into the soil will have a positive and not a negative effect."
Certified organic grower Rufus Haucke, who operates Keewaydin Farms in rural Viola with his partner Joy Miller, acknowledges the benefits of plastic mulch on crop yield. However, he has never been comfortable with the “one and done” single season approach and has opted to use landscape fabric which serves the same purpose and can be removed at the end of the crop year for reuse. “I have landscape fabric that we have been using for five years, and it is supposed to last up to twenty years,” he said. Farmers and the organic farming community “are starting to spend a lot more time thinking about the materials we are using and looking for ways to avoid plastic.” Haucke remains optimistic that ongoing research will discover sustainable mulch options that provide producers with a good yield and a profitable farming operation and do not harm the soil biology.
References: LyricsonDemand.com; UN Environment Programme, Plastic Leaching into Farmer’s Fields at Alarming Rate; Civil Eats, Ocean Plastic Is Bad, but Soil Plastic Pollution May Be Worse; Treehugger, What Is Plasticulture, and Is It Sustainable; Rodale Institute, Beyond Black Plastic