Comparative Analysis of Biodegradable Mulches on Soil Bacterial Community and Pepper Cultivation

Biodegradable mulch films (BMFs) are becoming increasingly popular in agricultural practices. However, research on the ecological impact of biodegradable mulch films on pepper–soil systems is still scarce. To compare the differential effects of BMFs and polyethylene (PE) mulch on soil chemical properties, soil bacterial community composition, and pepper cultivation, a study was conducted encompassing eight distinct treatments. These treatments included three varieties of polybutylene adipate terephthalate (PBAT) combined with polylactic acid (PLA) mulches: PP-JL, PP-SD, and PP-SH; a black polypropylene carbonate mulch (PPC-BK); a brown PPC mulch (PPC-BR); a polyethylene (PE) mulch; straw mulching (NCK); and an uncovered control (PCK). After applying mulches for 129 days, most PPC and PBAT + PLA films had reached the rupture phase, whereas the PE film was still in the induction phase. Pepper yield was obviously higher in all mulched treatments (4830 kg hm−1) than in the un-mulched control (3290 kg hm−1), especially the BMF PP-JL treatment, which showed the most notable improvements in yield. Although BMF treatments maintained a lower soil temperature than the PE film mulch, they were still higher than the un-mulched control. Furthermore, the soil bacterial community composition and ecological network were not markedly affected by different mulching conditions. However, the PP-SH treatment significantly increased the abundance of Pseudomonas, Nitrosomonas, and Streptomyces genera. Moreover, Lactobacillus and Gp16 were substantially more abundant in the PPC-black (BK) and PPC-brown (BR) treatments compared to the PE mulching treatment. This study could provide valuable insights into the ecological benefits of BMFs in pepper cultivation. However, as our experiments were conducted for only one season, it is imperative to undertake long-term experiments across consecutive seasons and years for a thorough understanding and comprehensive study.