Effects of pesticide sorption on biodegradable plastic degradation in agricultural soils

Overview

Biodegradable plastics are increasingly used in agriculture as alternatives to conventional mulches that leave long-lasting debris in soils. However, their full degradation under real field conditions depends on many factors that are rarely tested together. This research investigates how contact pesticides sprayed onto biodegradable mulch films are sorbed onto the plastic surface, change the plastisphere (the microbial community living on the plastic), and ultimately slow down the degradation process. The goal is to generate evidence that helps manufacturers, growers, and regulators select and design biodegradable mulches that truly degrade in pesticide-exposed agricultural environments.

Technical specifications

• Materials studied: commercial biodegradable mulch films including PLA, PBAT, PBS, and starch-based formulations.
• Exposure variables: different contact pesticides applied to the plastic surface prior to soil incubation.
• Test systems:
  • Lab phase: soil mesocosms under controlled moisture and temperature, with sampling of plastic debris at intervals to characterize the plastisphere and track degradation against untreated controls.
  • Greenhouse phase: selected plastics and pesticides incubated under varying moisture and temperature to assess environmental robustness.
• Measurements: pesticide sorption on plastic surfaces, shifts in plastisphere microbial communities, and degradation rates of the plastic films.
• Analytical approach: combines established methods from pesticide sorption studies, soil microbiome analysis, and plastisphere research to link three previously separate processes into a single framework.

Technology readiness level

The work is at an early-to-mid research stage. The team has already demonstrated that pesticides are sorbed onto agricultural plastics, and prior literature supports links between pesticides, soil microbiomes, and plastisphere composition. The next step is to integrate these findings through controlled lab mesocosm experiments followed by greenhouse validation. Outputs will be knowledge and design criteria for biodegradable mulch performance under pesticide exposure rather than a market-ready product, making the project well suited for collaborative research with agricultural plastic producers, pesticide manufacturers, and sustainability-focused partners.