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This experiment was conducted to screen the suitable mulching type of plastic film for Rosa roxburghii orchard, according to explore the effects of different color plastic film mulching on soil, shoot growth, flowering and fruit setting. Four different colors (colorless was marked as T1, red was T2, green was T3 and black was T4) of plastic film with PE material were selected in this study. The natural grass with no plastic film covering was taken as the control. The differences of soil physical properties, microbial carbon content, shoot growth, flowering, fruit setting and yield performance under different treatments were compared. The results showed that plastic film mulching could increase soil temperature in different degrees, and lead to an earlier phenological period, in which the flowering time of black and red plastic film mulching treatments was 4-5 days earlier than that of the control. Soil physical parameters such as salinity, volume water content, total dissolved solids, electrical conductivity and dielectric constant under the treatment of black plastic film were higher than those under the control, while other plastic films had no such effects but the soil physical properties were more stable. Covering with black and red plastic film could significantly inhibit the growth of weeds, and the biomass of weeds in the covered area was reduced by 88.36% and 89.5% respectively, which was significantly lower than that of other treatments and the control. All plastic film mulching treatments could increase the chlorophyll content of leaves, and green plastic film was the most beneficial to promote the growth of new shoots of R. roxburghii. The colorless and black plastic film mulching could significantly promote the flowering of R. roxburghii, and the fruit-bearing capacity in the early stage increased about 43.8% and 37% respectively compared with the control. Finally, the treatment with colorless plastic film had the most prominent effect of increasing the yield, which was 52.55% higher than that of the control. While the black plastic film lead to more fruit dropping during the fruit development, so that the final yield was only increased by 14.39% compared with the control. The results of this research showed that different color plastic films had their own advantages in improving or stabilizing soil physical parameters, promoting tree growth, inhibiting weeds and increasing yield, and could be used as needed in production. Among them, the colorless plastic film was particularly effective in increasing fruit yield, and could be suggested as the preferred plastic film type for cultivation of R. roxburghii. [ABSTRACT FROM AUTHOR]

Plastic products are widely used around the world, but waste plastic is not reasonably managed and causes serious plastic pollution. Biodegradable plastics (BPs) provide an alternative to conventional plastics, but not all BPs can be completely degraded under natural conditions. Instead, they may break down into microplastics (MPs) faster than conventional plastics, posing an additional threat to soil environment. In this paper, the definition, applications, and degradation behaviors of BPs, including biodegradable microplastics (BMPs), are reviewed, and we comprehensively summarized the eco-toxicological effects of BMPs in soil ecosystems, in terms of physical and chemical properties of soil, soil nutrient cycling, soil bacterial and fungal communities, soil flora and fauna. The compound effects of BMPs and other pollutants were also addressed. The results revealed that BMPs made different or more severely effects compared to conventional MPs. Overall, this review aims to address gaps in knowledge, shed light on the ecological effects of BPs and BMPs in soil. BPs are not a perfect substitute to solve plastic pollution, and further exploration should focus on their generation, environmental behavior, ecological impact and whether BMPs cause more harm than conventional MPs.

Currently, it is unclear whether degradable film mulching is a feasible viable alternative to non-degradable film mulching for improving crop productivity and soil environmental conditions. In the present study, a three-year-long field experiment was conducted to evaluate the effects of three alternative degradable films and a traditional plastic film (PF) on soil properties and peanut growth performance. Results showed that degradable films enhanced peanut yields by 6.0–14.3% compared to no mulching (CK), while reduced the peanut yield compared to PF. The results of the structural decomposition model analysis attributed the positive correlations between peanut yields and soil temperature, soil organic carbon, soil alkali-hydrolyzable nitrogen, soil microbial biomass carbon (MBC), and soil microbial biomass nitrogen (MBN). The degradable films decreased soil temperature, soil organic matter, soil alkali-hydrolyzable nitrogen content, MBC and MBN content by 0.12–11.8%, 1.40–10.9%, 1.90–9.91%, 2.31–13.2% and 12.7–34.2% compared to PF, respectively, despite they performed better effects on soil environment than CK. Moreover, the degradation rates of the three degradable films ranged from 7.38% to 91.3%. The aliphatic polyester polylactic acid-based film was found to be the best alternative because of improvement of soil environment and crop yield as well as superior degradation properties. [Display omitted] • Degradable plastic film mulching enhanced peanut yields as ODF > PLA > STF. • The enhanced peanut yields were due to the improved soil environment. • The degradation rates of three degradable films followed the order of STF > PLA >ODF. • Degradable films are alternatives to enhance crop yield with lower plastic pollution. [ABSTRACT FROM AUTHOR]

The inhomogeneity of plastisphere and soil may result in different microbial communities, thus potentially affecting soil functions. Biodegradable plastics offer an alternative to conventional plastics, nevertheless, the inadequate end-of-life treatment of biodegradable plastics may release more microplastics. Herein, we collected PE and PBAT/PLA microplastics in plastic-mulching farmland in Hebei, China. The bacterial communities of soil, PE and PBAT/PLA plastisphere were investigated using 16 S high-throughput sequencing. We found that the structure of bacterial communities in PBAT/PLA plastisphere were significantly distinct from PE plastisphere and soil. The alpha diversities in PBAT/PLA plastisphere were significantly lower than PE plastisphere and soil. Statistical analysis of differentially ASVs suggested that PBAT/PLA microplastics act as a filter, enriching taxa with the capability to degrade plastic polymers such as Proteobacteria and Actinobacteria. Compared to PE plastisphere, PBAT/PLA plastisphere has networks of less complexity, lower modularity, and more competitive interactions. Predicted metabolic pathways involved in human diseases, carbohydrate metabolism, amino acid metabolism, and xenobiotic biodegradation and metabolism were promoted in PBAT/PLA plastisphere, along with the facilitation in abundance of genes associated with carbon and nitrogen cycling. Our results highlighted the uniqueness of plastisphere of biodegradable microplastics from conventional microplastics and their potential impact on soil functions. [Display omitted] • Microbial community on PBAT/PLA microplastics differed structurally from soil and PE microplastics. • Potential plastic-degrading bacteria were enriched in PBAT/PLA plastisphere. • PBAT/PLA plastisphere has networks of less complexity and more competitive interactions. • Keystone species were Proteobacteria and Actinobacteriota. • Bacterial multifunctionality was promoted in PBAT/PLA plastisphere. [ABSTRACT FROM AUTHOR]

Plastic products are widely used around the world, but waste plastic is not reasonably managed and causes serious plastic pollution. Biodegradable plastics (BPs) provide an alternative to conventional plastics, but not all BPs can be completely degraded under natural conditions. Instead, they may break down into microplastics (MPs) faster than conventional plastics, posing an additional threat to soil environment. In this paper, the definition, applications, and degradation behaviors of BPs, including biodegradable microplastics (BMPs), are reviewed, and we comprehensively summarized the eco-toxicological effects of BMPs in soil ecosystems, in terms of physical and chemical properties of soil, soil nutrient cycling, soil bacterial and fungal communities, soil flora and fauna. The compound effects of BMPs and other pollutants were also addressed. The results revealed that BMPs made different or more severely effects compared to conventional MPs. Overall, this review aims to address gaps in knowledge, shed light on the ecological effects of BPs and BMPs in soil. BPs are not a perfect substitute to solve plastic pollution, and further exploration should focus on their generation, environmental behavior, ecological impact and whether BMPs cause more harm than conventional MPs. [ABSTRACT FROM AUTHOR]