China is expected to expand its use of environment-damaging plastic film to boost crop production, according to a Bloomberg News story.
The film traps moisture and heat, and helps control weeds and pests. It reduces water demand by 20-30 percent and it enables crops to be grown in both drier and colder environments.
It is used as a mulch over 12 percent of China’s farmland and on 93 percent of the country’s tobacco fields.
Overall, about 1.45 million metric tons of polyethylene are spread in sheets across 20 million ha (49 million acres) — an area about half the size of California — of farmland in China.
And use of the translucent material might exceed two million tons by 2024 and cover 22 million ha, according to Yan Changrong, a researcher with the Chinese Academy of Agricultural Sciences in Beijing.
The downside is that polypropylene film is not biodegradable and often not recycled.
Potentially cancer-causing toxins that can be released into the soil from the plastic residue are said to be present at levels of 60-300 kg per ha in some provinces.
While polyethylene contamination occurs worldwide, the threat is especially acute in China, where about a fifth of arable land contained levels of toxins exceeding national standards, according to 2014 government estimates.
The Bloomberg story is at: https://www.bloomberg.com/news/articles/2017-09-05/plastic-film-covering-12-of-china-s-farmland-contaminates-soil.