In the cold and cool region of northeastern China, low temperature and limited soil moisture retention constrain maize yield, and mulching is widely used to alleviate these limitations. To reduce the environmental risks associated with polyethylene (PE) film, a two-year field experiment (2024–2025) was conducted to evaluate biodegradable films suitable for maize production in this region. Five mulching treatments were tested, including PE film (T1) and four biodegradable options—polypropylene carbonate (PPC, T2), polybutylene adipate terephthalate (PBAT, T3), polylactic acid (PLA, T4), and a PBAT + PPC composite film (T5)—with no mulching as the control (CK). Across two growing seasons, T1–T5 increased the effective grain filling duration by 4.74–13.58%, raised grain auxin content during grain filling by 1.54–29.33%, and increased the two-year mean yield by 13.95–24.73% compared with CK. Notably, the PBAT + PPC composite film (T5) did not differ significantly from PE film (T1) in grain filling traits, hormone regulation, or yield improvement (p > 0.05), indicating that T5 is a promising and sustainable alternative to PE film for maize production in cold regions. These findings provide technical support for selecting and applying biodegradable mulch films in cold-region maize systems and contribute to environmentally sustainable high-yield cultivation.
Guo et al. (Fri,) studied this question.