Biodegradable Mulch Films Research Articles

Comparative life cycle assessment of polyethylene agricultural mulching film and alternative options including different end-of-life routes

With rising concerns about adverse impacts of agricultural plastic waste in the soil environment and microplastic problems, many options have been proposed to prevent agricultural plastic pollution. To evaluate the options environmentally, this study conducted a comparative life cycle assessment of mulching films with different thicknesses (0.01 mm and 0.014 mm), materials (polyethylene and poly (butylene adipate-co-terephthalate)), and end-of-life options (recycling, incineration and biodegradation). The results indicate that biodegradable film presents the lowest net environmental impacts in aquatic pollution and toxicity indicators, while the 0.014 mm polyethylene film performs the best in global warming potential and fossil resource depletion. Either reducing the soil content or increasing the collection rate of waste polyethylene films can reduce their environmental impacts, and the reducing proportions of 0.014 mm polyethylene films were found to be larger than those of 0.01 mm polyethylene films. In general, the biodegradable mulching film is found to be more environmental-friendly than polyethylene film, but potential improvement could be considered for greener design of the products by increasing biobased material. More efforts can be put on developing reliable inventory datasets of biodegradable materials production.

Accelerated degradation of plastic products via yeast enzyme treatment

Biodegradable plastics can solve the problem of unwanted plastics accumulating in the environment if they can be given the contradictory properties of durability in use and rapid degradation after use. Commercially available agricultural biodegradable mulch films are made from formulations containing polybutylene adipate-co-terephthalate (PBAT) to provide mechanical and UV resistance during the growing season. Although used films are ploughed into the soil using a tiller to promote decomposition, it is difficult if they remain durable. We showed that an enzyme produced by the leaf surface yeast Pseudozyma antarctica (PaE) degrades PBAT-containing films. In laboratory studies, PaE randomly cleaved the PBAT polymer chain and induced erosion of the film surface. In the field, commercial biodegradable films containing PBAT placed on ridges were weakened in both the warm and cold seasons by spraying the culture filtrate of P. antarctica. After the field was ploughed the next day, the size and total weight of residual film fragments decreased significantly (p < 0.05). Durable biodegradable plastics used in the field are degraded using PaE treatment and are broken down into small fragments by the plough. The resultant degradation products can then be more readily assimilated by many soil microorganisms.

Valorization of coffee wastes as plant growth promoter in mulching film production: A contribution to a circular economy

Food waste valorization, considered as energy and/or chemicals source, via biorefinery or biotechnology, gained great attention in recent years, because of the fast depletion of primary resources, increased waste generation and landfilling worldwide. Coffee by-products for example (i.e. coffee pulp, coffee husks, silver skin, spent coffee, etc.) have been investigated in different forms either as a source of antioxidant and valuable chemicals and as a filler in composites. A new valorization route for coffee silver skin (CSS), up to now just sent to damping, is here investigated: particulate bio-composites based on poly(butylene succinate-co-adipate) (PBSA), an aliphatic biodegradable polyester commercially available, have been formulated with up to a 30 wt% of CSS, in order to prepare mulching films for agriculture. The bacterial analysis of the filler indeed, has underlined the presence of potential Plant Growth-Promoting Bacteria species, mainly ascribed to the Bacillus genus, which can survive both the roasting and the compounding processes. The obtained composites have been characterized mechanically and thermally and their hydrophilic nature has been investigated by measuring their contact angle. Eventually, the bacteria release from the composite films has been examined by means of in-vitro tests. The plant growth promoting capability of the films was preliminarily evaluated in pot experiments using lettuce as a model crop. The composite films were able to release the endogenous bacteria in the soil and to stimulate plant and root growth of the assayed crop. The possibility to produce functionalized biodegradable mulching films by recycling agricultural wastes can thus be forecast, highlighting potential multiple advantages in terms of soil preservation/fertilization, decrease of polymeric materials in mulching products, exploitation of a waste.

Biodegradable mulch films significantly affected rhizosphere microbial communities and increased peanut yield

Biodegradable mulch films are widely used to replace conventional plastic films in agricultural fields. However, their ecological effects on different microbial communities that naturally inhabit agricultural fields are scarcely explored. Herein, differences in bacterial communities recovered from biofilms, bulk soil, and rhizosphere soil were comparatively assessed for polyethylene film (PE) and biodegradable mulch film (BDM) application in peanut planted fields. The results showed that the plastic film type significantly influenced the bacterial community in different ecological niches of agricultural fields (P < 0.001). Specifically, BDMs significantly increased the diversity and abundance of bacteria in the rhizosphere soil. The bacterial communities in each ecological niche were distinguishable from each other; bacterial communities in the rhizosphere soil showed the most pronounced response among different treatments. Acidobacteria and Pseudomonas were significantly enriched in the rhizosphere soil when BDMs were used. BDMs also increased the rhizosphere soil bacterial network complexity and stability. The enrichment of beneficial bacteria in the rhizosphere soil under BDMs may also have implications for the observed increase in peanut yield. Deepening analyses indicated that Pseudoxanthomonas and Glutamicibacter are biomarkers in biofilms of PE and BDMs respectively. Our study provides new insights into the consequences of the application of different types of plastic films on microbial communities in different ecological niches of agricultural fields.

Assessment of cryogenic pretreatment for simulating environmental weathering in the formation of surrogate micro- and nanoplastics from agricultural mulch film

Microplastics (MPs) and nanoplastics (NPs) from mulch films and other plastic materials employed in vegetable and small fruit production pose a major threat to agricultural ecosystems. For conducting controlled studies on MPs' and NPs' (MNPs') ecotoxicity to soil organisms and plants and fate and transport in soil, surrogate MNPs are required that mimic MNPs that form in agricultural fields. We have developed a procedure to prepare MPs from plastic films or pellets using mechanical milling and sieving, and conversion of the resultant MPs into NPs through wet grinding, both steps of which mimic the degradation and fragmentation of plastics in nature. The major goal of this study was to determine if cryogenic exposure of two biodegradable mulch films effectively mimics the embrittlement caused by environmental weathering in terms of the dimensional, thermal, chemical, and biodegradability properties of the formed MNPs. We found differences in size, surface charge, thermal and chemical properties, and biodegradability in soil between MNPs prepared from cryogenically treated vs. environmentally weathered films, related to the photochemical reactions occurring in the environment that were not mimicked by cryogenic treatment, such as depolymerization and cross-link formation. We also investigated the size reduction process for NPs and found that the size distribution was bimodal, with populations centered at 50 nm and 150–300 nm, and as the size reduction process progressed, the former subpopulation's proportion increased. The biodegradability of MPs in soil was greater than for NPs, a counter-intuitive trend since greater surface area exposure for NPs would increase biodegradability. The result isassociated with differences in surface and chemical properties and to minor components that are readily leached out during the formation of NPs. In summary, the use of weathered plastics as feedstock would likely produce MNPs that are more realistic than cryogenically-treated unweathered films for use in experimental studies.

Assessing Yield and Quality of Melon (Cucumis melo L.) Improved by Biodegradable Mulching Film.

Low-density polyethylene (LDPE) plastic mulching films have an important function, but at the end of their lifetime pose an economic and environmental problem in terms of their removal and disposal. Biodegradable mulching films represent an alternative to LDPE with the potential to avoid these environmental issues. In this preliminary study, we employed a biodegradable film based on Mater-Bi® (MB) in comparison with low-density polyethylene to assess their effect on the yield and particular quality traits (organoleptic and nutraceutical composition of the fruits) of muskmelon (cv Pregiato) grown on soils with different textures (clay-loam-CL and sandy loam-SL) in two private farms in South Italy. Soil temperature under the mulch was also measured. During the monitored periods, mean soil temperature under LDPE was higher (about 1.3 °C) than that under the biodegradable film and was higher in SL soil than in CL soil, at 25.5° and 24.2 °C, respectively. However, the biodegradable film was able to limit the daily temperature fluctuation, which was 1.7 °C in both soils compared with 2.3 °C recorded for LDPE. Fruit yields were higher with MB film than LDPE (+9.5%), irrespective of soil texture. MaterBi® also elicited increases in total soluble solids, polyphenols, flavonoids, and antioxidant activity compared with LDPE films: 13.3%, 22.4%, 27.2%, and 24.6%, respectively. Color parameters of flesh, namely brightness, chroma, and hue angle were better in fruits grown on LDPE. Our findings suggest that Mater-Bi® based biodegradable mulching film is a potentially valid alternative to traditional LDPE, particularly for obtaining the agronomical benefits outlined above and for promoting environmental sustainability due to its favourable biodegradable properties.

Factors affecting farmers' adoption of and willingness to pay for biodegradable mulch films in China

The technology of biodegradable mulch films (BDMs) is an environmentally-friendly substitute for polyethylene (PE) mulches in agricultural production. Given the technology is new to the market, it is not easy for farmers to adopt it. Additionally, farmers’ decision on BDMs adoption is a multiple-stage process. To understand the decision process, this paper employs a double hurdle model to explore the factors affecting farmers’ adoption and willingness to pay for BDMs using the sample data from China. The results show farmers follow a two-stage decision-making process, farmers have to overcome the first hurdle, i.e., adoption or non-adoption, and then decide how much they are willing to pay for BDMs. The role of technology-specific characteristics is more important than adopter-specific characteristics in the adoption of BDMs. Understanding the impact of factors on farmers’ decision-making process can assist policymakers in designing programs, specifically tackling difficulties confronting farmers at different stages of decision-making.

The long-term uncertainty of biodegradable mulch film residues and associated microplastics pollution on plant-soil health.

Biodegradable mulch film potentially offers an encouraging alternative to conventional (petroleum-based) plastic films. Since biodegradable films are more susceptible to rapid degradation, more microplastics (MPs) are likely to be generated than conventional films within the same time frame, probably leading to more severe MPs pollution and associated effects. However, the effect of biodegradable mulch film residues and associated MPs pollution on plant-soil health remains uncertainty. Here, we evaluated the potential effect of bio-MPs pollution on soil carbon (C) and nutrient (i.e., N and P) cycling, soil biology (microorganisms and mesofauna), and plant health, as these are crucial to agroecosystem functioning and the delivery of key ecosystem services. Unlike the inert (and therefore recalcitrant) C contained within petroleum-based MPs, at least 80% of the C from bio-MPs is converted to CO2, with up to 20% immobilized in living microbial biomass (i.e., < 0.05tC ha-1). Although biodegradable films are unlikely to be important in promoting soil C storage, they may accelerate microbial biomass turnover in the short term, as well as CO2 production. Compared to conventional MPs, bio-MPs degradation is more pronounced, thereby inducing greater alterations in microbial diversity and community composition. This may further alter N2O and CH4 emissions, and ultimately resulting in unpredictable consequences for global climate warming. The extent to which this may occur, however, has yet to be shown in either laboratory or field studies. In addition, bio-MPs have a large chance of forming nanoplastics, potentially causing a stronger toxic effect on plants relative to conventional MPs. Consequently, this would influence plant health, crop productivity, and food safety, leading to potential health risks. It is unclear, however, if these are direct effects on key plant processes (e.g. signaling, cell expansion) or indirect effects (e.g. nutrient deficiency or acidification). Overall, the question as to whether biodegradable mulch films offer a promising alternative to solve the conventional plastic legacy in soil over the long term remains unclear.

Response of Physiological Growth Characteristics of Rice to Different Biodegradable Mulching and Irrigation Methods in Cold Region of Northeast China

Highlights The tested biodegradable mulch film can be rapidly degraded in rice fields in cold regions and has good applicability. The degradation rate of white mulch film is faster than that of black film before the induction period, and the degradation law after the induction period is opposite. The combination of mulching film and water-saving irrigation can effectively enhance the photosynthetic capacity and dry matter transport of rice in cold regions. Through comprehensive evaluation, we found that the combination of ridge irrigation and mulching FC plastic film has the best effect on environmental protection and rice growth. Abstract. To reveal the mechanism of influence of different types of biodegradable plastic film mulching and irrigation combinations on the physiological growth characteristics of rice in cold regions, eight types of film mulching irrigation methods were designed, which combined four types of plastic film mulching and two types of irrigation methods for a total of nine treatments. The study analyzed the degradation law of degradable plastic film in rice fields in cold regions, and the effects of film-mulching irrigation methods on rice photosynthetic characteristics, dry matter transport, and rice yield. The results showed that the three biodegradable plastic films were suitable for the rice fields in the northeast cold region. Except for the jointing stage, mulching irrigation treatments could increase the chlorophyll content and net photosynthetic rate of rice, and the improvement degree showed a downward trend with the growth of rice. The film mulching irrigation treatments improved rice stems and leaves dry matter transport and grain contribution. The comprehensive evaluation based on the comprehensive index method showed that the combination of ridge irrigation and thin black biodegradable mulch is the best combination of biodegradable plastic film mulching and irrigation in the study area. Keywords: Biodegradable mulching, Comprehensive index method, Dry matter transportation, Irrigation method, Photosynthetic character.

Agronomic performances of biodegradable and non-biodegradable plastic film mulching on a maize cropping system in the semi-arid Loess Plateau, China

Biodegradable plastic film mulch (PFM) is considered an alternative to non-biodegradable PFM to mitigate the negative impacts of residual film. However, the agronomic performance of biodegradable PFM in comparison to non-biodegradable PFM still needs to be tested. In this study, we evaluated the effects of biodegradable and non-biodegradable PFM on soil physicochemical properties, microbial community, and enzyme activities, as well as maize growth performance. Biodegradable and non-biodegradable PFM both increased soil temperature, water content, N content, and microbial biomass and maize yield by up to 30%, but decreased soil enzyme activities as compared to no mulching (control, CK). Most soil physicochemical properties, microbial community, and enzyme activities were similar under non-biodegradable and biodegradable PFM at the early stages of maize growth. However, at the late stages, soil temperature, water content, mineral N, NO3--N, ammonia monooxygenase (AMO) activity, and total phospholipid fatty acids (PLFAs) decreased under biodegradable PFM owing to film fragmentation. White PFM increased soil temperature, water content, and total PLFAs at the early stages of maize growth but decreased soil mineral N and total PLFAs at the late stages, as compared to black PFM. As soil temperature and N availability were the major factors affecting soil microbial community, microbial activity decreased after the fragmentation of biodegradable PFM, owing to the decreased soil temperature, water content, and mineral N. Notably, biodegradable PFM could decrease NO3--N accumulation in topsoil by decreasing N transformation due to the lower microbial and N-related enzyme (e.g., AMO) activities, compared with non-biodegradable PFM, which may avoid negative environmental impacts, such as NO3--N leaching or gas emission after harvest. Maize yield, height, aboveground biomass, and N uptake under biodegradable PFM were similar to those under non-biodegradable PFM during maize growth, implying that biodegradable PFM has no negative impact on crop growth and yield. In general, biodegradable PFM was equivalent to non-biodegradable PFM in terms of maize yield increase and N uptake, but was environmentally friendly. Therefore, biodegradable PFM can be used as an alternative to non-biodegradable PFM in semi-arid areas for sustainable agricultural practices.

Preparation of bacterial cellulose film from rotten fruits for mulching film application

This research aims to reduce production capital costs and added value to natural products. The bio-mulching film was prepared by bacterial cellulose (BC) “Acetobacter xylinum”, extracted from three rotten fruits, grape, coconut, and pineapple under standard tests in the laboratory. The analysis from the FTIR technique confirmed to cellulose molecular vibration of BC films. XRD pattern was matched to structure crystallinity of JCPDS standard file which possessed a high percentage of crystallinity. The SEM micrographs were also revealed the 3D nanofiber network structure. The absorption capability of BC films could highly hold water in its structure. In addition, the mechanical properties of BC films came from rotten coconut, given the highest tensile strength (7.2 ± 1.1 MPa) according to nano-fiber symmetric with its dense structure. Nevertheless, the soil burial testing emphasized BC films could reduce soil temperature and increase moisture content in the soil as well. The biodegradation rate of BC films in 30 days was moderately fair. The BC film from rotten coconut had the slowest biodegradation rate (approximately 22.3 4.2%), applicable to biodegradable mulching film.

Biodegradable Mulch Films Based on Starch/Poly (Lactic Acid)/Poly (ε-Caprolactone) Ternary Blends

Biodegradable Mulch Films Based on Starch/Poly (Lactic Acid)/Poly (ε-Caprolactone) Ternary Blends

Isolation and Degradation Characteristics of PBAT Film Degrading Bacteria.

In recent years, PBAT (polybutylene adipate-co-terephthalate) mulch has become one of the most commonly used biodegradable mulching films. In this paper, five potential strains of PBAT film degrading bacteria were screened from the soil sample using PBAT film as the sole carbon source. A highly efficient PBAT degrading strain JZ1 was isolated by comparing the degradation performance of PBAT mulching film identified as Peribacillus frigoritolerans S2313 by 16S rDNA sequence analysis. The capacity of the strain to degrade PBAT film was optimized by adjusting the cultivation conditions such as nitrogen source, pH, and inoculum volume. After 8 weeks of cultivation, the actual degradation rate of the strain to PBAT mulch film reached 12.45%. SEM (scanning electron microscopy) coupled with EDX (energy dispersive spectroscopy) analysis showed that microbial degradation is an oxidation process and is mainly due to the amorphous regions of the PBAT film. The biodegradation of PBAT film by Peribacillus frigoritolerans may provide a promising method for regulating the degradation progress of PBAT film in the farmlands.

Biodegradable film mulching promotes better soil quality and increases summer maize grain yield in North China Plain

ABSTRACT Soil pollution caused by the residual polyethylene film is a potential threat to agricultural sustainability. Biodegradable films are generally effective alternatives to reduce this pollution. However, soil quality changes responding to continuous biodegradable film mulch are still unclear. To reveal the accumulative effects of biodegradable film mulch on soil quality, we conducted a positioning experiment from 2016 to 2019 in North China Plain (NCP). Four treatments, including transparent polyethylene film mulching (PM), transparent biodegradable film mulching (TM), black biodegradable film mulching (BM), and non-mulching (CK) were employed. The results showed that compared with CK, both BM and TM treatments significantly reduced soil bulk density and increased soil microbial activity and soil enzyme activity; however, BM and TM did not affect soil nutrient content. Compared with CK, BM treatment significantly increased soil quality index (SQI) by 7.2% (in 2019) due to higher soil fertility content and bioactivity; however, TM and PM treatments decreased SQI by 3.2% and 3.8%, respectively. Besides, compared with CK, BM significantly enhanced summer maize grain yield by 30.35%. Therefore, black biodegradable film is a potential alternative to polyethylene film to improve soil quality and maize production in NCP.

Preparation of a Biodegradable Mulch Film Exhibiting a High Photothermal Conversion Efficiency and Bioactive Effects

AbstractIn this study, chitosan (CS), polyvinylpyrrolidone (PVP), polydopamine (PDA), and tungsten trioxide are compounded via melt blending to prepare a CS/PVP/PDA/WO3 composite mulch. The morphological characteristics, thermogravimetric analysis, transmission performance, photothermal performance, and degradation performance of the mulch film and the effect of the CS/PVP/PDA/WO3 composite mulch film on the growth of Dianthus chinensis L. and cucumber seeds are studied. The results show that the CS/PVP/PDA/WO3 film exhibits a good thermal stability, biodegradability, UV resistance, photothermal conversion ability, and transmittance. Evaluation of the effect of this mulch film on the growth of crops shows that the film can promote the germination of seeds and increase the seedling growth rate.

Biodegradable Mulching Films Based on Polycaprolactone and Its Porous Structure Construction.

Polycaprolactone (PCL) is one of the promising linear aliphatic polyesters which can be used as mulching film. Although it has suitable glass transition temperature and good biodegradability, further practical applications are restricted by the limited temperature-increasing and moisturizing properties. The rational design of the PCL structure is a good strategy to enhance the related properties. In this study, thermally-induced phase separation (TIPS) was introduced to fabricate a PCL nanoporous thin film. The introduction of a nanoporous structure on the PCL surface (np-PCL) exhibited enhanced temperature-increasing and moisturizing properties when used as mulch film. In detail, the average soil temperature of np-PCL was increased to 17.81 °C, when compared with common PCL of 17.42 °C and PBAT of 17.50 °C, and approaches to PE of 18.02 °C. In terms of water vapor transmission rate, the value for np-PCL is 637 gm-2day-1, which was much less than the common PCL of 786 and PBAT of 890 gm-2day-1. As a result, the weed biomass under the np-PCL was suppressed to be 0.35 kg m-2, almost half of the common PCL and PBAT. In addition, the np-PCL shows good thermal stability with an onset decomposition temperature of 295 °C. The degradation mechanism and rate of the np-PCL in different pH environments were also studied to explore the influence of nanoporous structure. This work highlights the importance of the nanoporous structure in PCL to enhance the temperature-increasing and moisturizing properties of PCL-based biodegradable mulching film.

A method for the treatment of black tea waste: Converting it into liquid mulching film and solid mulching film

AbstractThis work was aim to prepare biodegradable mulching film from biomass materials to reduce the environmental pollution caused by plastics. Black tea waste was divided into two parts and combined with degradable materials such as polyvinyl alcohol and cellulose to prepare two degradable mulching films: liquid mulching film (LMF) and solid mulching film (SMF). The optimum formula was developed after studying the effects of various components of degradable mulching film on mechanical properties in both dry and wet circumstances. The properties of LMF and SMF were characterized and tested by scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), light transmittance test, contact angle test, water resistance test, artificial accelerated aging test, and degradation performance test. The results demonstrated that LMF and SMF had good mechanical properties, resistance to ultraviolet light, water resistance, aging resistance, and biodegradation. Using tea waste to prepare mulching film material has the advantages of no pollution, easy biodegradation, and good biocompatibility.

Ameliorating C and N balance without loss of productivity by applying mulching measures in rainfed areas

Farmland mulching is applied widely as a soil management practice, especially in rainfed areas with scarce water resources. However, it is not clear how continuous mulch application might affect the carbon and nitrogen budget in rainfed agroecosystems. Therefore, we evaluated the impacts of different mulching measures (SM: flat planting pattern with full straw mulching; RM: ridge–furrow construction with half plastic film mulching; PM: flat planting pattern with full plastic film mulching; BM: flat planting pattern with full biodegradable film mulching; and NM: conventional tillage without mulching) on the maize yield, net ecosystem carbon budget (NECB), net global warming potential (NGWP), greenhouse gas intensity (GHGI), and N surplus or deficiency. The results showed that compared with NM, the maize yield decreased significantly by 10.0% under SM, whereas the mulching treatments (RM, PM, and BM) significantly increased the maize yield by 15.1–24.4% (P < 0.05). SM, RM, and PM significantly increased CO2 emissions (24.8–38.2%), N2O emissions (21.1–47.1%), and NGWP (20.8–45.5%), but reduced NECB. By contrast, BM increased NECB and significantly reduced GHGI (P < 0.05). Regardless of the mulching method applied, the N balance indicated an N surplus. Each mulching treatment (SM, RM, PM, and BM) increased the harvested N removal (47.9–179.9 kg N ha–1) and decreased the N leaching loss (8.8–35.9 kg N ha–1). RM, PM, and BM inhibited the ammonia volatilization rate, whereas SM promoted it. PM and BM achieved a lower N surplus. In conclusion, biodegradable film mulching (BM) can significantly reduce GHGI and the risk of N losses while also ensuring high crop yields, and thus it can be used as a high-yield and sustainable production method in rainfed areas.

Modeling effects of biodegradable film mulching on evapotranspiration and crop yields in Inner Mongolia

The use of biodegradable film has been increasingly recommended as an alternative to conventional plastic films. Several studies have evaluated the applicability of biodegradable film mulching (BRM). However, the large-scale effects of BRM on the spatiotemporal distribution of evapotranspiration (ET) and crop yields remain unclear. Furthermore, existing DSSAT (decision support system for agrotechnology transfer) models cannot accurately represent crop yields, as they fail to account for the impact of the disintegration rates of biodegradable films (DR) on air temperature (Ta) compensation, which represents the effect of soil temperature changes in mulched conditions on crop growth in the form of air temperature changes. Therefore, this study proposed an improved DSSAT model under BRM (BDSSAT) by considering the impact of DR on Ta compensation, and the performance of the model was compared with those of the DSSAT and modified DSSAT (MDSSAT). These models were validated using observed data from nine typical experimental sites in Inner Mongolia from 2015 to 2018. Moreover, 96 meteorological stations and soil textures were selected to evaluate the effect of BRM on soil water storage (SWS) (the amount of water stored in a given soil body, mm), ET, and crop yields of the primary cultivated crops (sunflower, potato, corn). Our findings demonstrated that the BDSSAT model could accurately simulate the SWS, ET, and crop yield under BRM. The normalized root mean square error (nRMSE) of ET simulated by the BDSSAT model was 49.4 % and 66.3 % lower than that of the MDSSAT and DSSAT models, respectively. An apparent spatial difference in SWS, ET, and crop yield was found in different regions due to the differences in soil texture, meteorological data, and agricultural management strategy. The spatial distributions of ET and crop yield of sunflower, potato, and corn in different regions were largely consistent with the spatial distribution of SWS. Furthermore, the ET and crop yield of sunflower and potato crops in different regions increased with time (2015–2018) due to an increase in rainfall. However, these effects were not observed in corn yields in the eastern region. Additionally, the DR in the western, middle, and eastern regions should not exceed 55 %, 73 %, and 90 %, respectively, to ensure high field production (crop yield was higher than the historic average). Crop yields in different regions increased in response to future climate change, as the average Ta was projected to increase by 0.8 °C from 2019 to 2050, except for sunflower yields in the western region.

Continuous years of biodegradable film mulching enhances the soil environment and maize yield sustainability in the dryland of northwest China

Due to the limited disposal options for traditional polyethylene film (PF) mulch, interest is increasing in the use of biodegradable film (BF) mulching. However, little information is available regarding the impact of the continued use of BF on the soil environment and crop productivity. Therefore, we compared the effects of BF and PF on the soil total nitrogen (TN), soil organic carbon (SOC), soil carbon :nitrogen ratio (C:N), soil moisture, soil temperature (ST), leaf area index, accumulated aboveground biomass , grain yield, and water use efficiency (WUE) in the dryland of northwest China for four consecutive seasons. The results showed that BF and PF had similar effects on ST and soil moisture conservation in the early growth stage (0–60 days after sowing), but when the BF degraded, the ST and soil water content were significantly lower under BF than PF. After 60 days after sowing, the ST values were similar under BF and the control with no mulching (CK), which effectively alleviated the damage caused by high temperatures to a certain extent. The grain yield and WUE did not differ significantly under PF and BF, except in 2018. Compared with CK, the average grain yield and WUE increased by 12.8% and 6.8% under PF, respectively, and by 16.2% and 10.4% under BF. Both mulching methods reduced the SOC and TN contents in the 0–40 cm soil layer compared with the uncovered plots. However, they had different effects on the soil C:N where PF significantly reduced the C:N ratio whereas BF slightly increased it, thereby indicating that BF played an important role in maintaining the SOC and TN balance . Therefore, BF is recommended as a viable alternative to traditional PF for maize production in the dryland of northwest China. This study provides new evidence that BF can replace PF to address the problems of food security and residual film pollution in areas with similar conditions. • Biodegradable film (BF) effectively alleviates damage caused by high temperatures. • BF increased soil C:N to facilitate organic carbon fixation in soil. • BF can replace polyethylene film for sustainable maize production in dryland.