Search Results (92)

The practice in agriculture of spreading polyethylene (PE) film over the soil surface as mulch is a common, global practice that aids in conserving water, increasing crop yields, suppressing weed growth, and decreasing growing time. However, these films are typically only used for a single growing season, and thus, their use and non-biodegradability come with some serious environmental consequences due to their persistence in the soil and potential for microplastic pollution, particularly when retrieval and disposal options are poor. On the microscale, particles < 5 mm from degraded films have been observed to disrupt soil structure, impede water and nutrient cycling, and affect soil organisms and plant health. On the macroscale, there are obvious and serious environmental consequences associated with the burning of plastic film and its leakage from poorly managed landfills. To maintain the crop productivity afforded by mulching with PE film while avoiding the environmental downsides, the development and use of biodegradable polymer technologies is being explored. Here, the efficacy of a newly developed, water-dispersible, sprayable, and biodegradable polyester–urethane–urea (PEUU)-based polymer was compared with two commercial PE mulches, non-degradable polyethylene (NPE) and OPE (ox-degradable polyethylene), in a greenhouse tomato growth trial. Water savings and the effects on plant growth and soil characteristics were studied. It was found that PEUU provided similar water savings to the commercial PE-based mulches, up to 30–35%, while showing no deleterious effects on plant growth. The results should be taken as preliminary indications that the sprayable, biodegradable PEUU shows promise as a replacement for PE mulch, with further studies under outside field conditions warranted to assess its cost effectiveness in improving crop yields and, importantly, its longer-term impacts on soil and terrestrial fauna. Full article

Biodegradable mulch films (BDMs) are considered a promising solution for mitigating plastic residue pollution in agroecosystems. However, the degradation behavior and ecological impacts of their residues on soil–plant systems remain unclear. Here, a pot experiment was conducted using an acidic purple soil (AS), a neutral purple soil (NS), and a calcareous purple soil (CS) to investigate the degradation of 1% (w/w) microplastics derived from polyethylene mulch film (PE-MPs) and polybutylene adipate terephthalate/polylactic acid (PBAT/PLA) mulch film (Bio-MPs), as well as their effects on soil properties, bacterial communities, and radish growth. PE-MPs degraded slightly, while the degradation of Bio-MPs followed the order of NS > CS > AS. PE-MPs and Bio-MPs enhanced the nitrification and radish growth in AS but had no significant effects on soil properties and radish growth in CS. Bio-MPs notably increased the relative abundance of PBAT/PLA degradation-related bacteria, such as Ramlibacter, Bradyrhizobium, and Microbacterium, across the three soils. In NS, Bio-MPs raised soil pH and enriched nitrogen-fixing and denitrifying bacteria, leading to a decrease in NO₃⁻-N content and radish biomass. Overall, the effects of Bio-MPs on soil–plant systems varied with soil properties, which are closely related to their degradation rates. These findings highlight the need to assess the ecological risks of BDM residues before their large-scale use in agriculture. Full article

Soil microplastic pollution poses a significant threat to the integrity of terrestrial ecosystems and agricultural sustainability. This review provides a comprehensive synthesis of recent progress on soil microplastic (MP) sources, ecological impacts, and separation technologies. Agricultural practices (e.g., residual plastic mulch and wastewater irrigation) and atmospheric deposition serve as primary drivers of contamination accumulation, with pronounced spatial heterogeneity observed across regions. Predominant MP types such as polyethylene, polystyrene, and polypropylene disrupt soil structure and biogeochemical processes through three core mechanisms: physical interference, chemical toxicity, and biological accumulation. These particles further form carrier–pollutant complexes, exacerbating ecotoxicological impacts across trophic levels. While emerging separation techniques like magnetic separation and solvent extraction demonstrate enhanced efficiency, their implementation faces challenges stemming from soil matrix complexity and high operational costs. This article underscores the need for global collaborative efforts to accelerate innovation in biodegradable polymers, offering practical pathways for sustainable soil management. Full article

Agricultural production in Northwest China is widely constrained by residual plastic film pollution, excessive greenhouse gas emissions, and low productivity. Integrating biodegradable film with controlled-release nitrogen fertilizer offers a promising approach to optimize crop management, enhance yield, and improve environmental outcomes. In this study, three planting patterns (conventional flat planting, FP; ridge mulching with biodegradable film, BM; and ridge mulching with conventional plastic film, PM), two nitrogen fertilizer types (urea, U, and controlled-release nitrogen fertilizer, C), and four nitrogen application rates (0, 80, 160, and 240 kg·hm⁻²) were applied to systematically investigate their effects on alfalfa yield and N₂O emissions from grasslands. The results showed that BM and PM increased alfalfa yield by 23.49% and 18.65%, respectively, compared to FP, while C increased yield by 8.46% compared to urea. The highest yield (24.84 t·hm⁻²) was recorded under the BMC2 treatment, which was 97.11% higher than that of FPN0. N₂O emission flux and cumulative emissions increased with nitrogen application rate. Compared with U, C reduced cumulative N₂O emissions and greenhouse gas emission intensity (GHGI) by 23.89% and 25.84%, respectively. Compared to PM, BM reduced cumulative N₂O emissions and GHGI by 11.58% and 20.15%, respectively. Principal component analysis indicated that the combination of ridge mulching with biodegradable film and 160 kg·hm⁻² of C was optimal for simultaneously increasing alfalfa yield and reducing N₂O emissions, making it a suitable planting–fertilization strategy for the Yellow River irrigation district in Gansu and similar ecological regions. Full article

Biodegradable mulch film (BDM) is regarded as a key solution to combat plastic mulch film pollution due to its ability to degrade completely into CO₂ and H₂O through environmentally friendly microorganisms. However, commercial BDM often fails to degrade fully after use, leading to the accumulation of BDM residues in soil and their transformation into microplastics (MPs) via various processes, posing a threat to the soil ecosystem. Given these discrepancies between the theoretical and practical degradation performance of BDM, there is an urgent need to understand the impacts of BDM residues on plant growth and soil health. This research conducted pot experiments spanning the entire growth cycle of Chinese cabbage to evaluate the impact of PBST-BDM raw material (R), PBST-BDM residues (M), and PBST-BDM composting product (P) on crop growth and soil quality. The findings revealed that R treatments had a slight effect on Chinese cabbage growth (e.g., a 5.80% increase in emergence rate in R 1% treatment, p < 0.05), while M treatments significantly hindered the emergence rate, plant height, leaf area, and biomass accumulation of Chinese cabbage by 30.4% (p < 0.05), 2.71 cm (p < 0.05), 39.0% (p < 0.05), and 1.86 g (p < 0.05) in the M 1% treatment compared to the control group (CK). In contrast, P treatments enhanced Chinese cabbage growth, with greater improvements at higher weight ratios, resulting in increases of 8.89% (p < 0.05), 4.96 cm (p < 0.05), 36.3% (p < 0.05), and 2.31 g (p < 0.05) in the P 1% treatment. Microbial network topology in the M 1% treatment is highly variable, with the increased proportion of positive correlations in the P 1% treatment hinting at stronger symbiotic interactions between species (p < 0.05). Analysis results of PCoA and PLS-DA showed significant differences in microbial community and soil metabolites between M 1% treatment and CK (p < 0.05). These findings suggest that, although composting post-use BDM may reduce their negative ecological effects, possibly via accelerating the early breakdown of residues, the feasibility and scalability of this approach require further validation under real-world field conditions. Full article

Plastic film mulching is widely used in protected agriculture. However, the residues of various types of plastic films, as a consequence, severely affect soil quality. The most widely promoted alternative strategy is the use of biodegradable plastic films. Nevertheless, the research on the effects of different types of plastic films on soil properties remains insufficient. This study explored the impacts of different plastic film mulching on the physicochemical properties and microbial communities of soils for pepper cultivation, with three treatments: traditional polyethylene film (PE-Ctr), PBAT biodegradable film (PBAT bio), and reinforced polyethylene film (RPE). The results showed that the soil pH value was the highest in PE-Ctr treatment, and the soil organic matter content was higher in the biodegradable film treatment, while the electrical conductivity (EC), nitrate, and some cations (Ca²⁺, Mg²⁺) were higher in the RPE treatment. The contents of available trace element Zn, Fe, and Mn increased in the PBAT bio treatment. The bacterial richness and evenness indices were higher in PBAT bio treatment than those of other treatments. The fungal community had a relatively high richness, but a lower evenness, compared to the PE-Ctr and PBAT bio treatments. The use of different plastic films significantly affected the composition of soil bacteria, while differences in the composition of soil fungi were only observed between the PBAT bio and RPE treatments. Proteobacteria, Acidobacteriota, and Actinobacteriota were the most dominant bacterial phyla, and Ascomycota and Mortierellomycota were the dominant fungal phylum across all treatments. FAPROTAX functional prediction showed that the abundances of multiple functions of soil bacteria were higher in the RPE treatment, and the chemoheterotrophy function was higher in the PE treatment. FUNGuild analysis indicated that the trophic types and ecological function groups of soil fungi were more abundant in the PBAT bio treatment. Full article

Poly(butylene adipate-co-terephthalate) (PBAT) is a promising biodegradable polymer with balanced mechanical properties and excellent degradability, making it an ideal material to reduce plastic pollution. However, its susceptibility to ultraviolet (UV) degradation, due to photosensitive aromatic rings and carbonyl groups in its structure, limits its use in outdoor settings like mulch films. Conventional methods of incorporating small-molecule UV stabilizers face challenges such as poor compatibility, uneven dispersion, and migration under environmental conditions, reducing their effectiveness over time. This study developed a novel strategy to enhance PBAT’s UV resistance by chemically bonding UV-stabilizing moieties directly into its molecular chains to address these limitations. A novel UV absorber containing a polymerizable group was synthesized and copolymerized with PBAT’s main chain, creating an intrinsically UV-stable PBAT. The UV-stable PBAT was evaluated for UV resistance, mechanical performance, and durability through accelerated aging and solvent extraction tests. The results demonstrated that UV-stable PBAT exhibited exceptional light stabilization effects, with no detectable UV absorber leaching in ethanol even after 114 h, whereas PBAT blends lost nearly 90% of UV-0 within 24 h. Furthermore, UV-stable PBAT maintained 67.1% tensile strength and 48.8% elongation at break after aging, which exhibited the best mechanical retention performance. Even when subjected to solvent extraction, the 42.6% tensile strength retention outperformed the PBAT blends. This innovative chemical modification overcomes the limitations of additive-based stabilization, offering improved durability, compatibility, and performance in outdoor applications. Our research provides key insights into the fundamental properties of PBAT films for UV resistance, demonstrating their potential for use in demanding fields such as agricultural films. Full article

Biodegradable mulch films not only provide similar field benefits to conventional mulch films but also degrade naturally, rendering them an effective alternative to traditional polyethylene mulch films for mitigating “white pollution”. However, recent studies have focused on the material selection and soil ecological impacts of biodegradable mulch films, while their effects on soil water temperature regulation and root architecture in drip-irrigated rice cultivation remain unclear. To address this research gap, in this study, various treatments including no mulch (NM), conventional plastic mulch (PM), and four types of biodegradable mulch films (BM-W₁, BM-B₁, BM-B₂, and BM-B₃) were established, and their effects on the soil hydrothermal flux, root architecture, biomass accumulation, and resource use efficiency of drip-irrigated rice were analyzed at different growth stages. The results indicated the following: (1) Compared with the NM treatment, film mulching increased the soil hydrothermal fluxes and water retention capacity, thereby promoting root growth and biomass accumulation, ultimately increasing the effective panicle number and grain yield. (2) Among the biodegradable film treatments, BM-B₃ (with a degradation period of 105 days) maintained relatively higher soil temperature for a longer duration, which increased surface root distribution in the mid-to-late growth stages, further improving fine root growth and biomass accumulation, consequently enhancing both yield and water use efficiency. In contrast, BM-B₁ and BM-B₂ exhibited excessively rapid degradation rates, leading to significant fluctuations in soil moisture and temperature, thereby negatively affecting water supply and nutrient uptake and ultimately restricting root growth and development. (3) The entropy weight (EW) technique for order of preference by similarity to ideal solution (TOPSIS) model results revealed that although the PM treatment was more advantageous in terms of soil temperature, root dry weight, and soil moisture content, BM-B₃ provided a slightly higher yield than the PM treatment did and offered the advantage of biodegradability, making it a preferred alternative to conventional mulch film. In summary, this study revealed the mechanism by which biodegradable mulch films enhanced biomass accumulation and yield formation in drip-irrigated rice production by optimizing soil hydrothermal dynamics and root architecture, thereby exploring their potential as replacements for conventional mulch films. These findings provide a theoretical basis for the efficient and sustainable production of drip-irrigated rice in arid regions. Full article

To address the problem of environmental pollution caused by the extensive use of low-density polyethylene (LDPE) mulch film, this study developed a novel sprayable mulch using natural fibers and biodegradable polymers. Urea–formaldehyde resin (UF), strengthened with polyvinyl alcohol (PVA), was used as a modifier to induce beneficial physicochemical structural changes in PVA-modified urea–formaldehyde (PUF) resins. Characterization of these resins was conducted using Fourier transformation infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Preparation of the biodegradable mulch was conducted using Xuan paper waste residue (XP) as an enhancer, with PUF as the auxiliary agent. The resulting film (PUF-XP) was examined for differences in thickness, morphological characterization, and rate of weight loss, and the effects of different covering films on cucumber growth, root development, soil temperature, and weed control were evaluated. Characterization reveals that when the PVA content was 4% (W4UF), the film had the lowest free formaldehyde content (0.26%) and highest elongation at break (5.70%). In addition, W4UF could easily undergo thermal degradation at 278.4 °C and possessed a close-knit, three-dimensional structural network. W4UF was then mixed with paper powder and water in various proportions to produce three mulch films (BioT1, BioT2, and BioT3) that demonstrated excellent water retention and heat preservation and inhibited weed growth by 68.8–96.8%. Compared to no mulching (NM), BioT1 increased both the specific root length and root density, as well as improved the plant height, stem diameter, and total biomass of the cucumbers by 43.5%, 34.1%, and 33.9%, respectively. Therefore, a mass ratio of paper powder, water, and W4UF of 1:30:2 produced a biodegradable mulch film that could be used as an alternative to LDPE, mitigating the environmental pollution rendered by synthetic plastic mulch films and offering the potential for a sustainable agricultural application. Full article

The disposal of orchard garbage (including pruning branches, fallen leaves, and non-biodegradable materials such as pesticide containers and plastic film) poses major difficulties for horticultural production and soil sustainability. Unlike general agricultural garbage, orchard garbage often contains both biodegradable organic matter and hazardous pollutants, which complicates efficient recycling. Traditional manual sorting methods are labour-intensive and inefficient in large-scale operations. To this end, we propose a lightweight YOLOv7-based detection model tailored for the orchard environment. By replacing the CSPDarknet53 backbone with MobileNetV3 and GhostNet, an average accuracy (mAP) of 84.4% is achieved, while the computational load of the original model is only 16%. Meanwhile, a supervised comparative learning strategy further strengthens feature discrimination between horticulturally relevant categories and can distinguish compost pruning residues from toxic materials. Experiments on a dataset containing 16 orchard-specific garbage types (e.g., pineapple shells, plastic mulch, and fertiliser bags) show that the model has high classification accuracy, especially for materials commonly found in tropical orchards. The lightweight nature of the algorithm allows for real-time deployment on edge devices such as drones or robotic platforms, and future integration with robotic arms for automated collection and sorting. By converting garbage into a compostable resource and separating contaminants, the technology is aligned with the country’s garbage segregation initiatives and global sustainability goals, providing a scalable pathway to reconcile ecological preservation and horticultural efficiency. Full article

As a substitute for conventional plastic mulch, biodegradable mulch film (BDM) has been popular in agricultural systems in recent years. However, studies focusing on the systematic effect of BDM residues on the soil microbiome and metabolome remain obscure. Thus, a mesocosm experiment was established, and it aimed to investigate the effects of concentrations of poly(butylene adipate-co-terephthalate) (PBAT) microplastics (MPs) on soil microbial ecology and plant (Lactuca sativa) fitness. Metagenomics and metabolomics analyses were deployed to explore the response of soil microbial communities, functional shifts, and metabolites under different dosages of PBAT MPs (CK, 0.1%, 1%, and 5% w/w). The results showed that PBAT MPs did not significantly affect the morphological traits (shoot length and leaf dry weight) of the plant. Regarding plant biochemical indicators, the highest concentration of PBAT could increase the proline and soluble protein contents compared to low- and medium-dosage PBAT treatments with high malonaldehyde (MDA) or soluble sugar contents. Soil physicochemical properties like the available phosphorus and potassium, ammonium N and nitrate N contents were decreased in a dose-dependent manner. Metagenomics analysis revealed that only a high concentration of PBAT had more profound effects on the soil microbial community composition, diversity, and function when compared to the control (CK). In particular, a 5% PBAT treatment could result in the development of some microbial biomarkers, such as Paraburkholderia and Rhizobium, which had beneficial functions. Moreover, metabolomics analysis showed that 5% PBAT differentially affected the soil metabolites, with a high abundance of bioactives like peptides, organic acid, and nepetaside. This work underscores that soil could recruit certain microbes and bioactive substances to resist external high-PBAT stress. PBAT might pose little threat to the soil ecosystem, and its application is beneficial for soil health management. Full article

To address low productivity and water constraints in lucerne fields of China’s Gansu Yellow River Irrigation Region, this study optimized lucerne (Medicago sativa L.) cultivation through synergistic planting nitrogen regimes. A two-year field trial (2021–2022) evaluated three systems: ridge-furrow with ordinary mulch (PM), ridge-furrow with biodegradable mulch (BM), and conventional flat planting (FP), under four controlled-release N rates (0, 80, 160, 240 kg ha⁻¹). Multidimensional assessments included growth dynamics, dry matter yield, forage quality (crude protein [CP], acid/neutral detergent fiber [ADF/NDF], relative feed value [RFV]), and resource efficiency metrics (water use efficiency [WUE], irrigation WUE [IWUE], partial factor productivity of N [PFPN], agronomic N use efficiency [ANUE]). The results showed the following: (1) Compared with conventional flat planting, ridge planting with film mulching significantly promoted lucerne growth, with ordinary plastic film providing a stronger effect than biodegradable film. Plant height and stem diameter exhibited a quadratic response to elevated nitrogen (N) application rates under identical planting patterns, peaking at intermediate N levels before declining with further increases. (2) Ridge planting with both ordinary plastic film and biodegradable film combined with an appropriate N rate improved lucerne yield and quality. In particular, the PMN2 treatment reached the highest value of yield (14,600 kg ha⁻¹), CP (19.19%) and RFV (124.18), and the lowest value of ADF (29.63%) and NDF (48.86%), and all of them were significantly better than the other treatments (p < 0.05). (3) WUE, IWUE, PFPN, and ANUE followed the pattern PM > BM > FP. With increasing N application rates, WUE, IWUE, and ANUE initially rose and then declined, peaking under N2, whereas PFPN showed a decreasing trend and reached its maximum under N1. Principal component analysis revealed that ridge planting with ordinary plastic film combined with 160 kg·ha⁻¹ N (PMN2) optimized lucerne performance, achieving balanced improvements in yield, forage quality, and water–nitrogen use efficiency. This regimen is recommended as the optimal strategy for lucerne cultivation in the Gansu Yellow River Irrigation Region and analogous ecoregions. Full article

The increasing environmental concerns regarding plastic waste, especially in agriculture, have driven the search for sustainable alternatives. Agricultural plastics, such as mulching films and greenhouse covers, are heavily reliant on petrochemical-derived materials, which persist in the environment and contribute to long-term pollution. This study explores the use of biodegradable biocomposites made from steam explosion-treated chicken feathers and various polymer matrices to address these issues. Chicken feathers, a waste by-product of the poultry industry, present an excellent biodegradability as a result of the steam explosion treatment and contain nitrogen, potentially enhancing soil fertility. The biocomposites were characterized by thermal stability, mechanical properties, and biodegradability, and ecotoxicity assessments were carried out studying the incorporation of feathers into the soil. Results showed that the incorporation of treated chicken feathers increased the water absorption capacity of the composites, promoting faster disintegration and biodegradation. In particular, biocomposites made with polyhydroxyalkanoates and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) exhibited a significant increase in degradation rates, from 3–10% in the first month for pure matrices to 40–50% when reinforced with treated feathers. Meanwhile, those made from polylactic acid showed slower degradation. Furthermore, the addition of feathers positively influenced crop growth at low concentrations, acting as a slow-release fertilizer. However, high concentrations of feathers negatively affect plant growth due to excess nitrogen. These findings highlight the potential of poultry feathers as a valuable, sustainable filler for agricultural bioplastics, contributing to waste valorization and environmentally friendly farming practices. Full article

Agricultural plastic mulch film, valued for its superior heat insulation and moisture retention, is widely used globally but has led to significant microplastic accumulation in soils, threatening agricultural ecosystems. This paper reviews its development and environmental impact, focusing on recycling and upcycling technologies, particularly catalytic recovery methods (with nearly 100% conversion efficiency) such as photocatalysis, thermocatalysis, and photothermal catalysis. It analyzes technical challenges and future directions in upcycling, emphasizing the role of catalysis in converting waste plastic mulch into hydrocarbon resources. This paper also evaluates the progress and challenges of biodegradable alternatives. By offering scientific insights and innovative approaches, it aims to reduce plastic mulch pollution, enhance resource utilization, and promote sustainable agriculture. Full article

In northern China, the production of millet is constrained by water scarcity, necessitating suitable agronomic measures to realize its yield potential. Mulching effectively conserves soil moisture and increases the yield. However, the yield effect varies with the climatic conditions and field management. A meta-analysis of 751 experimental datasets from 58 peer-reviewed papers explored the impact of mulching on the millet yield, yield composition, and water use efficiency (WUE), considering 11 factors. The results showed that, compared to traditional flat planting without mulching, mulching significantly increased the millet yield and WUE by 30.9% and 27.3%, respectively, and also enhanced the yield composition. For optimal results under mulching, the planting density should be less than 300,000 ha⁻¹, with nitrogen, phosphorus, and potassium fertilizer rates below 60 kg·ha⁻¹. Sites with an average temperature below 10 °C, Huangmian soil, or in the northwest region showed superior yield effects from mulching. The annual rainfall and planting methods had no significant impact on the yield, yield composition, and WUE. The variety “Longgu” exhibited the highest yield increase of 63.9%. Biodegradable plastic film mulch showed the most significant yield increase of 61.7%. Overall, mulching should be adapted to the local conditions, and appropriate field management practices should be selected to promote stable increases in the millet yield and WUE. Full article