Agronomic performance of polyethylene and biodegradable plastic film mulches in a maize cropping system in a humid continental climate.

Plastic polyethylene mulch has been widely used in crop production, but also causes environmental pollution if plastic residues accumulate in soil. Biodegradable plastic mulches (BDM) are a potential solution to problems caused by polyethylene mulches, as BDMs are designed be tilled into the soil after the growing season and then biodegrade. However, the agronomic performance of BDMs still needs to be tested for comparison to polyethylene mulch. We carried out a two-year field experiment in 2018 and 2019 in a typical humid continental climate in Northeast China. Maize was planted in a ridge-furrow pattern, with mulching treatments consisting of no mulch (control), clear BDM, black BDM, clear polyethylene, and black polyethylene. Clear mulches increased soil temperature when compared to no mulch control treatments, while black mulches decreased or did not change soil temperature during the early growing season. Soil temperature and root morphology were similar between BDM and polyethylene mulches for a given type of plastic color. Maize yield did not differ across all the treatments. Maize protein, fat, N and P contents were generally higher for black BDM than other treatments, suggesting that maize quality benefited especially from black BDM. Overall, these results show that, in a humid continental climate, the agronomic performance of clear and black BDMs was equivalent to, or better than, that of polyethylene plastic mulches for maize production.