Just days earlier, as if on cue, the Chinese government released Friday the draft of a law that would ban the use of very thin plastic film mulch.
“We found that the use of plastic mulch can indeed increase crop yields on average by 25%–42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%),” according to the meta-study published April 12 in Global Change Biology. “However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term.”
Plastic film is often seen in the United States on strawberry fields. But China has led the world in using it, particularly in arid regions, with increased crop production in the first year and wealthier farmers as a result.
But the same plastic now threatens that productivity and wealth, according to the study led by scientists from the Chinese Academy of Agricultural Sciences and the University of Melbourne.
The meta-analysis incorporates the results of 110 peer-reviewed studies and concludeds that residues from plastic mulch damage crop yield, plant height, root weight, and soil properties including soil water-evaporation capacity, soil water-infiltration rate, soil organic matter and soil available phosphorus.
China has an estimated 550,800 tons of plastic residue lingering in its croplands from plastic films that were not fully recovered.
“These physical soil changes help to explain the reduction in root weight, which in turn affect the nutrient uptake of crops and ultimately, result in the reduction of crop yield,” the authors write.
Published on forbes.com