Life cycle assessment of biodegradable mulch films in strawberry production under alternative end-of-life scenarios.
Abstract
Biodegradable mulch films (BDMs) can reduce agricultural plastic waste, but their environmental benefits depend on film composition, material properties, and end-of-life (EoL) management. This study conducted a cradle-to-grave life cycle assessment of poly(butylene adipate-co-terephthalate)/poly(lactic acid) (PBAT/PLA; PPLA) and poly(butylene adipate-co-terephthalate)/thermoplastic starch (PBAT/TPS; PTPS) mulch films in California strawberry production. Three BDM EoL scenarios were evaluated: soil biodegradation (SB), composting (CP), and anaerobic digestion (AD), with landfilled polyethylene mulch film (PEM-LF) as baseline. CP and AD were modeled as complementary routes for the recoverable film fraction. BDM scenarios reduced cradle-to-grave impacts by 7.50-9.02% relative to PEM-LF per functional unit, increasing to 12.32-18.21% on an equal areal-weight basis, through reductions in fossil fuel depletion, eutrophication, and ecotoxicity. PEM-LF performed worst because PEM manufacturing advantages were outweighed by LF ecotoxicity and eutrophication burdens. SB provided the greatest benefit by avoiding waste collection and disposal and crediting biomass formation as soil amendment. AD also performed favorably through biogas energy recovery, especially PTPS-AD, which was comparable to SB. CP was the least favorable BDM EoL strategy but remained better than PEM-LF. This study identified fossil-derived polyester content as the main target for reducing BDM manufacturing impacts, as PBAT contributed >90% of PPLA impacts and 68-96% in PTPS, including about 93% of global warming potential in both. Sensitivity analysis showed that lower fossil-derived polyester content, greater AD biomethane potential, shorter EoL transport distances, and greater SB biodegradation improved BDM performance. This study informs sustainable mulch use and waste management decisions by growers, policymakers, and waste managers.