Field evidence demonstrates soil plastics erode rhizomicrobiome networks and alter plant physiology
Plastic pollution in terrestrial and marine environments poses a profound and long-lasting risk to ecosystem sustainability, food security, and human health. Our understanding of how plastics affect agroecosystems, particularly phytobiomes, remains limited, despite soils being a major sink. In a three-year field study, we show that 1% plastic residue contamination (w/v) alters soil physical properties, including water-holding capacity, and that the residues fragment into smaller particles. We then assessed whether the contamination affected the plant and rhizosphere microbiome using two representative crops. We observed more discolored and cracked seeds, as well as immature root nodules, in soybean plants grown in 1% plastic-contaminated soil, whereas other visible growth indicators in soybeans and cucumbers were largely unaffected under agricultural field conditions. However, proteome and biochemical analyses revealed alterations in photosynthesis and stress-related responses in both crops grown in soils contaminated with 1% plastic residues over three years. Plastic contamination shifted microbial community structures and rewired network topology in the rhizosphere of soybean and cucumber plants, and this effect intensified over time. We conclude that plastic contamination perturbs plant health and soil microbial networks, demonstrating the need for continued monitoring and targeted management strategies to safeguard agroecosystem resilience.