Plastic Film Research Articles

Valorization of whey through green synthesis of silver nanoparticles for developing biodegradable plastic films with bactericide properties

This study explores the synthesis of silver nanoparticles (AgNPs) using untreated whey as a green approach, followed by their integration into biodegradable gelatin films for potential applications in antimicrobial packaging. UV–visible spectroscopy and scanning electron microscopy confirm the successful synthesis of AgNPs, which are seamlessly incorporated into flexible and semi-transparent gelatin films. Comparing films with and without AgNPs, subtle changes are observed in UV–visible and Fourier-transform infrared spectra that are attributed to the low AgNP concentrations. However, the resulting films with AgNPs exhibit effective bactericidal efficacy against E. coli. Moreover, soil burial tests demonstrate significant biodegradability, with up to 80% mass loss within two weeks, showing comparable rates between films with and without AgNPs. These results show the prospects of whey-derived AgNPs in the development of sustainable, antimicrobial biodegradable films with potential applications in various industries.

Study on the Characteristics of Residual Film–Soil–Root Stubble Complex in Maize Stubble Fields of the Hexi Corridor and Establishment of a Discrete Element Model

Plastic film mulching is one of the key technologies for improving agricultural productivity in arid and semi-arid regions. However, residual plastic film can severely disrupt the structure of the topsoil in farmland, leading to a decrease in crop yield. The Hexi Corridor, as the largest seed maize production base in the arid regions of Northwest China, is facing an increasingly prominent issue of residual plastic film recovery. This study designed experiments based on the typical maize planting model in the Hexi Corridor. A discrete element simulation model of the residual film–soil–root stubble complex was established using the Bonding-V2 model and API rapid filling technology. The reliability of the simulation model was verified through shear and puncture tests. The study revealed that the soil type in the Hexi Corridor is heavy sandy soil. The differences between the average maximum shear forces in the simulated and actual shear tests for root stubble–soil complexes at depths of 30 mm, 50 mm, and 100 mm were 4.8%, 6.4%, and 6.5%, respectively. Additionally, the differences in the average maximum vertical loading forces in the simulated and actual puncture tests for root stubble–soil complexes at depths of 50 mm and 100 mm were 6.4% and 12.37%, respectively. The small discrepancies between the simulated and actual values, along with the consistency of particle movement trends with real-world conditions, confirmed the reliability and accuracy of the simulation model. This indicates that the established discrete element flexible model can effectively represent actual field conditions, providing discrete element model parameters and theoretical support for optimizing the design of key components in China’s mechanized root stubble handling and residual film recovery machinery.

Development of biodegradable plastic films from cassava starch

Plastic has become part of daily life because it is used in all industrial applications. Although it is beneficial and practical, it is the material that generates the most pollution in ecosystems. Therefore, the main objective of this research is to produce plastic films capable of degrading the environment in a shorter time (bioplastics). For this purpose, different samples were made with cassava starch (pulp or commercial), using amounts in the solution of 4% w/v and 30% w/w of cassava starch and glycerol, respectively, considering variations between the percentages of chitosan. The results showed that it is possible to obtain bioplastic by the casting method with the mixture of cassava starch (pulp or commercial), glycerol, and chitosan. Likewise, thanks to the laboratory tests carried out, was possible to determine that the use of commercial starch to produce biodegradable plastic films significantly favors moisture adsorption, solubility, and biodegradability, compared to starch extracted from cassava by hand, with good statistics validity of the analyzed data.

Biodegradable plastic film mulch increases the mineralisation of organic amendments and prevents nitrate leaching during the growing season in organic vegetable production

AbstractIntroductionOrganic vegetable production relies on inputs of organic forms of nitrogen (N). This presents a challenge as it needs to be mineralised by the soil microbial community. Difficulties matching the timing and rate of organic N amendments to crop demand could potentially lead to high rates of nitrate leaching. The use of plastic film mulch (PFM) has the potential to increase crop yield, accelerate N mineralisation, reduce rainfall infiltration and therefore N leaching. Biodegradable PFM reduces the risk of contaminating soil with plastics. Although these positive effects have been proven in major conventionally grown commodity crops, the effects of PFMs are poorly understood in organic vegetable crops, particularly in moist temperate climates prone to N losses via winter leaching.Materials & MethodsOur plot‐scale field experiment attempted to quantify the effect of biodegradable PFM on N leaching and N mineralisation in organic lettuce production in the presence and absence of biodegradable PFM. It took place in one season within a longer‐term experimental organic vegetable rotation.ResultsWe used two methods to measure the rate of carbon and N mineralisation: the buried bag method showed biodegradable PFM resulted in no additional N mineralisation; however, the ion exchange membrane method indicated an increase in N mineralisation of 30%. During heavy rainfall at the end of the growing season, nitrate leaching was observed only in the non‐PFM plots, leading to N losses equivalent to 6.3 g N m−2. This led to surplus mineral N at harvest of 18.1 g N m−2 in the PFM treatment and 8.6 g N m−2 in the corresponding unmulched plots. This did not lead to more leaching in the mulched plots in the following 6 months.ConclusionIn conclusion, our evidence supports the use of biodegradable PFMs to enhance the sustainability of organic vegetable production systems in temperate climates.

Dynamic borate ester bond reinforced hydroxyethyl cellulose/corn starch crosslinked film for simple recycling and regeneration

Endowing biodegradable plastics with easy recyclability can reduce competition with food resources and further enhance their environmental friendliness. In this work, 4-carboxyphenylboronic acid was grafted onto the side chains of hydroxyethyl cellulose and compounded with inexpensive cornstarch. Upon the introduction of tannic acid, stable and reversible borate ester bond rapidly formed, yielding composite biodegradable plastic films with outstanding mechanical properties and facile recyclability. The formation of a dynamic cross-linked network mitigates the aggregation of gelatinized starch molecules, enhancing the flexibility and durability of the crosslinked film. Testing revealed that while maintaining high tensile strength, the elongation at break of the crosslinked film increased by 952.86 %. The static water contact angle was improved from 32.74° to 78.82°, with a change of <5° within 1 min, demonstrating enhanced water resistance. Excellent antioxidant and thermal stability were also characterized, the crosslinked film can be easily dissolved by heating in water at pH = 6.5 and reshaped in water at pH = 7.2. After five times of regeneration, the tensile strength loss was as low as 5.68 %. This eco-friendly and efficient recycling process is promising during green chemistry.

Phytolacca americana extract as a quality-enhancing factor for biodegradable double-layered films based on furcellaran and gelatin – Property assessment

For the first time, novel active double-layered films based on furcellaran (FUR) and gelatin (GEL) with the addition of Phytolacca americana (PA) extract were obtained. The 1st layer consisted of FUR and GEL, while the aqueous extract of P. americana berries was added in three different concentrations to the 2nd FUR-based layer. The films were characterised by good mechanical (TS range of 0.0011–0.0013 MPa, EAB range between 30.38 %–33.51 %) and water properties (WVTR range of 574.74–588.49 g/m2xd). Structural analysis (SEM and AFM) confirmed good film structure: regular, without cracks or air bubbles. The films showed antioxidant activity tested via the Folin-Ciocâlteu method (4.77–20.70 mg GAExg−1), FRAP assay (0.18–3.40 mM TExg−1) and CUPRAC assay (48.63–53.99 mM TExg−1). The film with the highest PA concentration (6 %) demonstrated the ability to neutralise free radicals, DPPH• and ABTS2+•, at the levels of 1.97 % and 17.34 %, respectively. The ecotoxicity test performed on Lepidium sativum seeds confirmed the lack of ecotoxic film aspects. The biodegradation test indicated that the films are biodegradable. The obtained films can be a good alternative to plastic packaging films (used in the food packaging industry), which are currently a global problem related to the development of post-consumer plastics.

The Influence of Rural Ecological Environment Development by China's Industrialization Process

This article aims to solve the problem of heavy pollution load in rural ecological environment at present. This article elaborates on the relevant concepts and theories of rural industrialization and ecological environment protection, mainly using a combination of qualitative and quantitative methods to analyze the current situation of rural ecological environment pollution in the research area. The research results indicate that the current rural ecological environment pollution load in China is heavy and severe, especially the use of fertilizers, pesticides, agricultural plastic films, livestock and poultry breeding, rural life, and township enterprise production, which have caused varying degrees of harm to the regional rural ecological environment. Therefore, effective measures must be taken to achieve the organic combination of rural industrialization and ecological environment protection. This article provides guidance for promoting the optimization and upgrading of rural industrial structure, achieving a win-win situation of economic and ecological benefits.

Chitosan films tailored with deep eutectic solvent extracts from Hibiscus sabdariffa: Fabrication and characterization

Natural polymers are the most promising alternatives to petroleum-based plastics for developing biodegradable food packaging films. However, the brittleness and lack of active protection of films from most natural polymers pose a challenge to their practical application. The addition of plasticizers and natural extracts to these films is considered an effective solution to address these issues. In this study, the potential for the use of deep eutectic solvents (DESs) and DES extracts derived from Hibiscus sabdariffa in the production of chitosan films and their effects on their mechanical and antioxidant properties were examined. Initially, the extraction efficacy of DESs composed of choline chloride (ChCl) and various carboxylic acids (citric, lactic, tartaric, and oxalic acids) was evaluated in terms of phenolic and anthocyanin contents along with antioxidant activities. Optimal results were achieved with the utilization of ChCl-oxalic acid as the extraction medium. Subsequently, chitosan films were fabricated by introducing DESs and DES extracts as plasticizers and compared with glycerol-plasticized chitosan films. The incorporation of DESs and DES extracts into the film matrix led to a notable reduction (11.78–14.82%) in moisture content compared with glycerol (25.34%). Notably, using ChCl-tartaric acid improved the tensile strength, while ChCl-citric acid enhanced the film flexibility. Films containing ChCl-tartaric acid demonstrated exceptional light barrier properties. SEM analysis revealed an interaction between chitosan and DESs, which was further corroborated by FTIR and XRD. Additionally, DES extracts provided superior antioxidant activity to the films than their pure DESs. These findings suggest a significant potential for DES extracts from Hibiscus sabdariffa as bioactive agents and plasticizers in chitosan films.

Temperature sensitivity of soil respiration to elevated temperature and nitrogen availability

Plastic film mulching (PFM) and nitrogen (N) fertilization are two important agricultural management methods that are used to enhance crop yields in semi-arid dryland agriculture. However, the impacts of PFM and N fertilization on the temperature sensitivity (Q10) of soil respiration (Rt), particularly its heterotrophic (Rh) and autotrophic (Ra) components, remain unclear. To investigate this, a trenching experiment was carried out between 2019 and 2021 in a rainfed maize-cultivated cropland that had been under cultivation for 7 years. There were four treatments: no PFM and N fertilization (control), full PFM without N fertilization (PFM), 150 kg N ha–1 fertilization without PFM (Nfer), and full PFM with 150 kg N ha–1 fertilization (PFM+Nfer). PFM and N fertilization not only enhanced crop yield and root biomass but also increased soil total respiration (Rt) and its components, due to improved soil hydrothermal conditions with PFM and increased N availability with N fertilization. Soil hydrothermal conditions and root biomass were identified as the most important factors influencing Rh and Ra, respectively. The greater increase in Ra (84 %–212 %) compared to Rh (9 %–29 %) resulted in a decrease in the proportion of Rh in Rt decreasing from 81.2 % in the control to 58 % under the PFM+Nfer treatment. The Rh/Rt ratio decreased in all three treatments compared to the control (p < 0.05). The increase in Rh under PFM led to a decrease in soil organic carbon (SOC) by 17 %. Specifically, the soil labile C content (i.e. LFOC 44 %) decreased more under PFM and PFM+Nfer (p < 0.05) compared to control, but not under the Nfer treatment (p > 0.05). Plastic film mulching increased the Q10 of Rh (p < 0.05) through decrease the content of soil labile C, whereas N fertilization had no effect (p > 0.05). Both PFM and N fertilization increased the Q10 of Ra (p < 0.05) by increasing root biomass. The impact of Ra’s Q10 (0.66) on Rt’s Q10 is greater compared to Rh’s Q10 (0.31). To our knowledge, this is the first long-term field study to examine the response of Rt components and their Q10 to PFM and N fertilization. Our results highlight that soil labile C and root biomass are the determining factors for the Q10 of Rh and Ra, respectively. We emphasize the importance of accurately modeling the temperature responses of Rh and Ra when predicting Rt under climate change scenarios.

Field-based assessment of the effect of conventional and biodegradable plastic mulch film on nitrogen partitioning, soil microbial diversity, and maize biomass

In an agricultural context, the use of conventional low-density polyethylene (LDPE) and biodegradable plastic mulch film has been actively promoted, however, the effects on physical and biochemical soil properties, crop growth dynamics, yield, and nutrient cycling of conventional and biodegradable mulch film use in a temperate climate remain largely undetermined. Here, we conducted a field experiment, exploring the effects of no mulch (control), conventional (LDPE), and biodegradable (PLA/PBAT) plastic mulch film on soil and crop (Zea mays L.) nitrogen (N) partitioning after application of 15N-labelled ammonium-nitrate fertiliser. Further, we also investigated the treatment effects on soil physical and biochemical properties (e.g., microbial diversity, compound-specific microbial 15N incorporation, N dynamics), plant development, as well as monitoring the biotic and abiotic degradation of the plastic mulch films. We found that conventional mulch film increased crop yield by 25 % and 15N uptake by 34 % compared to the control, simultaneously reducing 15N retention by 40 % in the topsoil (0–10 cm), but not affecting microbial N use efficiency and N transformation and incorporation into the protein pool. Biodegradable film application resulted in similar biomass (306 ± 14 g plant−1) to both control (275 ± 14 g plant−1) and conventional mulch (344 ± 20 g plant−1) treatments, but significantly reduced 15N crop uptake by 63 % compared to the conventional mulch film. We ascribe this to the accelerated mechanical breakdown and faster degradation of the biodegradable mulch film during the growing season. These findings suggest that current biodegradable plastic mulch film polymer blends may not be a suitable alternative to conventional mulch film in terms of short-term productivity and N use efficiency in a temperate climate for maize production.

A Review of Recent Developments in Edible Films and Coatings-Focus on Whey-Based Materials.

Packaging for food products is particularly important to preserve product quality and shelf life. The most used materials for food packaging are plastic, glass, metal, and paper. Plastic films produced based on petroleum are widely used for packaging because they have good mechanical properties and help preserve the characteristics of food. However, environmental concerns are leading the trend towards biopolymers. Films and coatings based on biopolymers have been extensively studied in recent years, as they cause less impact on the environment, can be obtained from renewable sources or by-products, are relatively abundant, have a good coating and film-forming capacity, are biodegradable and have nutritional properties that can be beneficial to human health. Whey protein-based films have demonstrated good mechanical resistance and a good barrier to gases when at low relative humidity levels, in addition to demonstrating an excellent barrier to aromatic compounds and especially oils. The use of whey proteins for films or coatings has been extensively studied, as these proteins are edible, have high nutritional value, and are biodegradable. Thus, the main objective of this document was to review new methodologies to improve the physicochemical properties of whey protein films and coatings. Importance will also be given to the combinations of whey proteins with other polymers and the development of new techniques that allow the manipulation of structures at a molecular level. The controlled release and mass transfer of new biomaterials and the improvement of the design of films and packaging materials with the desired functional properties can increase the quality of the films and, consequently, broaden their applications.

Investigation of bisphenol S (BPS) in packaged fish, meat, cheese, and price labels on their corresponding packages

As an alternative to bisphenol A (BPA), bisphenol S (BPS) has been used as an ink developer in thermal paper products including price labels on food packaging which have been suggested as the sources of BPS found at high levels in packaged fish samples. BPS in the printed price labels glued onto the outside of plastic film could migrate indirectly from the printed surface through the paper, adhesive and film into the food. In order to investigate if price labels could also be the sources of BPS detected in the meat samples in our previous studies, meat and other food samples packaged under different conditions were collected, and BPS in these samples together with the price labels on the corresponding packaging were extracted with solvent followed by solid phase extraction and stable isotope dilution LC-MS/MS analysis. BPS was detected at very high levels (161.7–222.4 µg/cm2) in all the five sticker type of price labels, indicating BPS being the dominant if not the sole ink developer. BPS was also detected in all the 26 continuous roll type of price labels but at very low levels (0.017–18 ng/cm2), indicating that the dominant ink developer is likely one of the other alternatives, rather than BPS. Despite BPS being detected in all price labels on packaging of fish, meat, and cheese samples, BPS was not detected or detected in only a few fish, meat, and cheese samples at levels considerably lower than the current EU specific migration limit (SML) of 50 ng/g food for BPS authorised under Regulation (EU) 10/2011.

Production Optimization of Premium Food Can with Distortion Printing under Waving Requirement

This research aims to propose a novel approach for evaluating and minimizing scraps in an industrial production of premium food cans with distortion printing. Beyond conventional formability criteria, a waving requirement is introduced to ensure aesthetic quality of the printed graphics. The research focuses on real production conditions, specifically involving double-cold-reduced (DR) low-carbon steel sheets and chromium-coated tin-free steel with a thickness of 0.16 mm. The sheets are laminated on both sides with a plastic film prior to undergoing distortion printing on the exterior. Subsequently, a blank is subjected to a drawing-redrawing process to form a food can. To address challenges associated with characterizing these thin sheets, a material parameter identification method is proposed and demonstrated. The thickness profile and flange length are identified as key criteria for this identification process. Measurements of thickness distribution and flange length are obtained using digital image correlation (DIC) and microscopy techniques. Within the manufacturing system, uncertainties related to material properties and forming processes can result in scraps or defects. To analyze these processes, finite element analysis (FEA) is employed and validated through experiments. For the evaluation of scrap rates, uncertainty propagation is conducted using a metamodeling technique, specifically employing radial basis function (RBF) neural networks. The study concludes by offering process optimization recommendations aimed at reducing the scrap rate.

Metabolomics and microbiomics revealed the combined effects of different-sized polystyrene microplastics and imidacloprid on earthworm intestinal health and function

The coexistence of pesticides and plastic film residues in agricultural soils poses a significant threat to soil organisms due to their potential long-term contamination and combined toxic effects. Specifically, earthworms are at risk of simultaneously ingesting residual pesticides and microplastics, yet the impact of this combined exposure on their intestinal health and function remains poorly understood. In this study, earthworm (Eisenia fetida) were single and combined exposed to three particle sizes (10 μm, 500 μm, and 2 mm) of polyethylene microplastics (PE MPs) and imidacloprid (IMI) for 28 days, respectively. Our findings underscore that compared to single exposures, the combined exposure inflicted more profound injuries on intestinal tissues and elicited a heightened activation of intestinal digestive enzymes. Furthermore, the combined exposure significantly perturbed the relative abundance of several pivotal metabolic-associated gut microbiota, fostering an enrichment of pathogenic species. Metabolomics analysis showed combined exposure increased differential metabolites, disrupting amino acid, fatty acid, and carbohydrate metabolism in earthworm intestines, potentially hindering nutrient absorption and causing toxic metabolite accumulation. An integrated omics analysis implies that combined exposures have the potential to disrupt the relative abundance of crucial gut microbiota in earthworms, thereby altering their intestinal metabolism and subsequently impacting intestinal health and functionality. Overall, the results reveal that combined exposure of IMI and PE MPs exacerbate the negative effects on earthworm gut health, and this study holds significant implications for the holistic understanding of the combined toxic effects of microplastics and pesticide on soil ecosystems.

Enhanced pollutant degradation via green-synthesized core-shell mesoporous Si@Fe magnetic nanoparticles immobilized with metagenomic laccase

With rapid industrial expansion, environmental pollution from emerging contaminants has increased, posing severe ecosystem threats. Laccases offer an eco-friendly solution for degrading hazardous substances, but their use as free-form biocatalysts face challenges. This study immobilized laccase (PersiLac1) on green-synthesized Si@Fe nanoparticles (MSFM NPs) to remove pollutants like Malachite Green-containing wastewater and degrade plastic films. Characterization techniques (FTIR, VSM, XRD, SEM, EDS, BET) confirmed the properties and structure of MSFM NPs, revealing a surface area of 31.297 m2.g−1 and a pore diameter of 12.267 nm. The immobilized PersiLac1 showed enhanced activity across various temperatures and pH levels, retaining over 82 % activity after 15 cycles at 80°C with minimal leaching. It demonstrated higher stability, half-life, and decimal reduction time than free laccase. Under 1 M NaCl, its activity was 1.8 times higher than the non-immobilized enzyme. The immobilized laccase removed 98.11 % of Malachite Green-containing wastewater and retained 82.92 % activity over twenty cycles of dye removal. Additionally, FTIR and SEM confirmed superior plastic degradation under saline conditions. These findings suggest that immobilizing PersiLac1 on magnetic nanoparticles enhances its function and potential for contaminant removal. Future research should focus on scalable, cost-effective laccase immobilization methods for large-scale environmental applications.

Soil Erosion Characteristics of the Agricultural Terrace Induced by Heavy Rainfalls on Chinese Loess Plateau: A Case Study

Terrace erosion has become increasingly pronounced due to the rising incidence of heavy rainfalls resulting from global climate change; however, the processes and mechanisms governing erosion of loess terraces during such events remain poorly understood. A field investigation was performed following a heavy rainfall event in the Tangjiahe Basin to examine the soil erosion characteristics of loess terraces subjected to heavy rainfall events. The results show that various types of erosion occurred on the terraced fields, including rill, gully, and scour hole in water erosion, and sink hole, collapse, and shallow landslide in gravity erosion. Rill erosion and shallow landslide erosion exhibited the highest frequency of occurrence on the new and old terraces, respectively. The erosion moduli of the gully, scour hole, and sink hole on the new terraces were 171.0%, 119.5%, and 308.7% greater than those on the old terraces, respectively. In contrast, lower moduli of collapse and landslide were observed on the new terraces in comparison to the old terraces, reflecting reductions of 34.2% and 23.4%, respectively. Furthermore, the modulus of water erosion (32,102 t/km2) was 4.5 times that of gravity erosion on the new terraces. Conversely, on the old terrace, the modulus of gravity erosion (8804.1 t/km2) exceeded that of water erosion by 14.5%. Gully erosion and collapse dominated the erosion processes, contributing 67.8% and 9.4% to soil erosion on the new terraces and 38.7% and 34.0%, respectively, on the old terraces. In the study area, the new terraces experienced significantly greater erosion (39,252 t/km2) compared to the old terraces (16,491 t/km2). Plastic film mulching, loose and bare ridges and walls, inclined terrace platforms, and high terrace walls, as well as the developing flow paths, might be the key factors promoting the severe erosion of the terraces during heavy rainfall. Improvements in terrace design, construction technologies, temporary protective measures, agricultural techniques, and management strategies could enhance the prevention of soil erosion on terraces during heavy rainfall events.

A low-energy, low-toxicity, hydrophobic cellulose membrane derived from waste fiber lunch boxes

Plastic film packaging is a significant contributor to plastic pollution, which has created growing demands to replace it with sustainable and environmentally-friendly cellulose films. In this study, waste bamboo fiber dinner boxes were used to produce nanocellulose films. The bamboo fiber lunch boxes were delignified and then fully cut and dissociated into fibers. A hydrophobic coating made from beeswax was developed to protect tableware. Bamboo nanocellulose films exhibited varying thicknesses, an average tensile strength of 81.4 MPa, and approximately 70 % crystallinity. After hydrophobic modification, the water contact angle increased to 103°, indicating improved water repellency. The treated film was also less toxic, making it suitable for packaging films that directly contact food. However, when acetone-diluted beeswax was used as a hydrophobic coating, the cellulose film formed after volatilization was significantly more toxic. The results demonstrated the potential in excellent hydrophobicity, strength and low toxicity of using beeswax-hydrophobic films for food-contact packaging.

Enhancing soil gross nitrogen transformation through regulation of microbial nitrogen-cycling genes by biodegradable microplastics

Microplastics (MPs) in agricultural plastic film mulching system changes microbial functions and nutrient dynamics in soils. However, how biodegradable MPs impact the soil gross nitrogen (N) transformations and crop N uptake remain significantly unknown. In this study, we conducted a paired labeling 15N tracer experiment and microbial N-cycling gene analysis to investigate the dynamics and mechanisms of soil gross N transformation processes in soils amended with conventional (polyethylene, PE) and biodegradable (polybutylene adipate co-terephthalate, PBAT) MPs at concentrations of 0 %, 0.5 %, and 2 % (w/w). The biodegradable MPs-amended soils showed higher gross N mineralization rates (0.5–16 times) and plant N uptake rates (16–32 %) than soils without MPs (CK) and with conventional MPs. The MPs (both PE and PBAT) with high concentration (2 %) increased gross N mineralization rates compared to low concentration (0.5 %). Compare to CK, MPs decreased the soil gross nitrification rates, except for PBAT with 2 % concentration; while PE with 0.5 % concentration and PBAT with 2 % concentration increased but PBAT with 0.5 % concentration decreased the gross N immobilization rates significantly. The results indicated that there were both a concentration effect and a material effect of MPs on soil gross N transformations. Biodegradable MPs increased N-cycling gene abundance by 60–103 %; while there was no difference in the abundance of total N-cycling genes between soils without MPs and with conventional MPs. In summary, biodegradable MPs increased N cycling gene abundance by providing enriched nutrient substrates and enhancing microbial biomass, thereby promoting gross N transformation processes and maize N uptake in short-term. These findings provide insights into the potential consequences associated with the exposure of biodegradable MPs, particularly their impact on soil N cycling processes.

The Impacts of High-Standard Farmland Construction on Cultivated Land Improvement in China

The construction of high-standard farmland has emerged as a prominent strategy to increase the total arable land area and augment cultivated land quality. This paper endeavors to scrutinize the policy impacts of this measure on elevating cultivated land quality and increasing land area in China. We employ an instrumental variable model with two-way fixed effects to quantitatively analyze the impact of the construction of high-standard farmland on the area and quality of cultivated land, based on panel data from 30 sample provinces in China from 2009 to 2018. Our results indicate that for every additional 10,000 hectares of high-standard farmland construction, the cultivated land area per person increased by 0.004 hectares, and the overall quality improved by 0.004 grade. The mechanism analysis further shows that constructing high-standard farmland indirectly alleviates cultivated land quality by reducing farmers’ use of chemical fertilizers, plastic film, and pesticides. The results imply that the ongoing construction of high-standard farmland remains a pivotal element in ensuring the sustainable utilization of cultivated land resources and achieving food security and agricultural modernization goals in China.

Effects of biodegradation of starch-nanocellulose films incorporated with black tea extract on soil quality

This study aimed to investigate the biodegradation behaviour of starch/nanocellulose/black tea extract (SNBTE) films in a 30-day soil burial test. The SNBTE films were prepared by mixing commercial starch, nanocellulose (2, 4, and 6%), and an aqueous solution of black tea extract by a simple mixing and casting process. The chemical and morphological properties of the SNBTE films before and after biodegradation were characterized using the following analytical techniques such as field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and fourier transform infrared (FTIR). The changes in soil composition, namely pH, electrical conductivity (EC), moisture content, water holding capacity (WHC), soil respiration, total nitrogen, weight mean diameter (MDW), and geometric mean diameter (GMD), as a result of the biodegradation process, were also estimated. The results showed that the films exhibited considerable biodegradability (35–67%) within 30 days while increasing soil nutrients. The addition of black tea extract reduced the biodegradation rate due to its polyphenol content, which likely resulted in a reduction in microbial activity. The addition of nanocellulose (2–6% weight of starch) increased the tensile strength, but decreased the elongation at break of the films. These results suggest that starch nanocellulose and SNBTE films are not only biodegradable under soil conditions but also positively contribute to soil health, highlighting their potential as an environmentally friendly alternative to traditional plastic films in the packaging industry.