Plastic is everywhere, including the mulch covering our farms

While shops like Twist and Sprout are working to reduce plastic use on the consumer end of the food supply chain, there is a large amount of plastic used on our farms. From an article in the BBC, "Plastic is omnipresent on farms. It is used to wrap silage, to cover crops, in tubing for irrigation and to transport feed and fertiliser. The biggest contributor to this problem, making up over 40% of the total agri-plastic market, are plastic sheets that are spread over the soil to serve as a sort of plastic mulch."

This plastic mulch is used for some good reasons, and has its benefits. "They suppress the growth of weeds, increase fertiliser uptake, regulate temperature and humidity, and protect plants and soil from bad weather."

Plastic mulch covers the soil when growing many types of vegetable crops

Mulching crops, that is, covering the soil while the plants are growing, has been long known to improve crop and soil outcomes. Plastic mulch increases yields as well; however, it does not improve soil outcomes. In fact, "It also alters the soil in harmful ways. Research has shown that the thinner the film, the more difficult it is to remove without leaving microplastics in the soil, where they can remain for decades."

Mulch made from organic matter will improve the soil over time, returning nutrients from the mulch to the soil. It can also be left in place to biodegrade, or tilled into the soil to increase soil carbon. Plastic mulch does not have this benefit.

While organic mulch can be reused or composted, plastic mulch cannot. "Plastic used on farms is typically difficult and expensive to recycle because it becomes contaminated with soil, pesticides and fertiliser."

The BBC article discusses some biodegradable plastic options. However, I don't believe this is the way that agriculture will go. As diesel, plastic and other oil-derived products become more expensive, machinery and plastic will be used less and less on farms. Biodegradable or bioplastics also require substantial amounts of energy to produce, which can only come from fossil fuels, so they will not immediately replace the plastic mulch requirements. We will have to switch back to organic mulch, and more human labour will be required to produce and lay this mulch. Tilling will be less common because of the effort involved, so mulch will stay on the ground longer, much like occurs in nature. The article claims that plastic mulch is something that "many farmers could address without dramatic changes to how they work". I'm not sure about that one.

Read the whole article here.