Film Mulching Research Articles

Evolution of hotspots and research trends in agricultural mulch film research: a bibliometric review

Agricultural mulch film (AMF) can increase the soil temperature, reduce the evaporation of water and soil erosion, control the number of weeds and pests, and improve the yield and quality of crops. However, the environmental pollution caused by AMF residues is becoming serious and has attracted increasing amounts of research. Research on AMF is a complex subject with diverse content and rich perspectives. Currently, there have been few systematic reviews of the use of AMF. To comprehensively and deeply understand the current status, hotspots, and trends of research on AMF, this paper conducted a bibliometric analysis of AMF literature from 1960 to 2022. Results are as follows: the overall publication volume in the field of AMF has increased 1960 to 2022. The top three countries contributing to publication volume include China, United States (US) and India, which are also the main collaborating nations. Notably, cooperation between China and US is the most frequent, and a cluster constituted by European nations serve as a primary collaborator for other countries. Owing to the introduction and development of the concept of degradable plastics, the field entered a period of rapid growth after 1970 and has primarily focused on continuous development in the areas of horticulture and environmental science. Current research on AMF primarily aims to: 1) develop applications that are aimed at enhancing the yield and quality of crops, and 2) improve the materials used to produce AMF to reduce its environmental impact. The persistent hotspots of research in AMF revolve around modifying the soil microclimate, promoting crop growth and development, and increasing crop yields. Frontier AMF research includes: exploring crop quality enhancement mechanisms, developing low-cost biodegradable film technologies and their natural degradation effects, and investigating AMF’s impact on soil nitrous oxide emissions and associated mechanisms.

EFFECTS OF RAINWATER HARVESTING PRACTICES ON BIOMASS YIELD AND MORPHOMETRIC TRAITS OF SORGHUM (Sorghum bicolor L. Moench) IN SEMI-ARID KITUI COUNTY, KENYA

<p><strong>Background</strong>: Sorghum is an important source of fodder in the semi-arid areas of Kenya. However, its biomass yield has remained low due to the low soil moisture content which is associated with low rainfall. <strong> Objective:</strong> To evaluate the synergistic effects of combining rainwater harvesting practices on biomass yield and the morphometric traits of sorghum in semi-arid Kitui County. <strong>Methodology</strong>: The study was conducted in a randomized complete block design under rainfed conditions between March and August 2021 at the Research Farm of South Eastern Kenya University. It had twelve treatments, including three farming systems (conventional flat planting, ridge and furrow, and zai pits) with three soil mulching types (transparent plastic film mulch, black plastic film mulch, and grass mulch). The farming systems without mulching were used as control treatments. Data were subjected to analysis of variance and means were separated using Fisher’s protected Least Significant Difference test at 0.05 %. <strong>Results:</strong> The zai pits with black plastic film mulch and flat planting with grass mulch had the highest and lowest moisture content of 68.65% and 52.5% respectively compared to flat planting. The highest biomass yield was observed in ridge-furrow with black plastic film mulch (3283.33kg ha-<sup>1</sup>) and ridge–furrow with transparent plastic film mulch (3266.03) and was not significantly different. The lowest biomass yield was recorded in conventional flat planting and zai pits and was not significantly different. In all treatments, there was a significant increase (p ≤ 0.05) in morphometric traits. <strong>Implications: </strong>The farming system and the type of soil mulching determined the increase of soil moisture content, biomass yield, and morphometric traits. <strong>Conclusion</strong>: Combining ridge-furrow and black plastic mulch is recommended to improve the biomass yield of sorghum in semi-arid Kitui County, and other areas with similar agroecological conditions.</p>

Plastic film mulch use efficiency in agricultural production: a regional analysis in China

Plastic film mulch use efficiency in agricultural production: a regional analysis in China

Film mulching counteracts the adverse effects of mild moisture deficiency, and improves the quality and yield of Cyperus esculentus. L grass and tuber in the oasis area of Tarim Basin.

Plastic film mulching (PFM) and deficit irrigation (DI) are vital water-saving approaches in arid agriculture. Cyperus esculentus is a significant crop in dry zones. However, scant data exists on the impacts of these water-saving methods on C. esculentus yield and quality. Using randomized block experiment design. Three irrigation strategies were tested: CK (standard irrigation), RW20 (20% water reduction), and RW40 (40% water reduction). Mulchin treatments included film mulching (FM) and no film mulching (NFM). Results revealed substantial effects of film mulching and drip irrigation on soil nutrients and physical properties, with minor influence on grass, root, and tuber stoichiometry. PF treatment, DI treatments, and their interaction significantly affected C. esculentus forage and tuber yields. Initially, grass and tuber yields increased and then decreased with reduced irrigation. The highest yields were under RW20 (3716.31 and 4758.19 kg/ha). FM increased grass and tuber yield by 17.99% and 8.46%, respectively, over NFM. The water reduction augmented the biomass distribuiton of the leaf and root, while reducing the tuber biomass in NFM. FM significantely impacted grass ether extract content, while reduced water influenced grass and tuber crude protein and tuber ether extract content. Mild water stress increased ether extract, crude protein, and soluble matter in grass and tubers, while excessive RW decreased them. Integrating soil traits, nutrients, yield, and quality, findings indicate C.esculentus yield and quality primarily hinge on soil water content, pond hydrogenase, and electrical conductivity. Based on this results, the recommended strategy is to reduce irrigation by 20% for cultivating C. esculentus in this area.

Alfalfa Cultivation Patterns in the Yellow River Irrigation Area on Soil Water and Nitrogen Use Efficiency

Establishing lucerne field is an efficient way to protect natural steppes, alleviate conflicts between meadows and livestock, and promote the development of animal husbandry. However, problems such as extensive field management, valuing yield over quality, and low resource utilization are endemic in production. Exploring reasonable cultivation patterns can contribute to improving the current situation of artificial grassland production and promoting the high-quality development of husbandry and prataculture. Lucerne the field experiment was carried out in Jingtai, Gansu Province, China in 2021–2022; this study compared and analyzed the effects of three cultivation patterns—ridge tillage with plastic film mulching (PM), ridge tillage with biodegradable film mulching (BM), and traditional flat planting (FP)—on soil water, heat, and fertilizer, as well as lucerne growth, yield, quality, and water and nitrogen use efficiency. The results show that: (1) during the growth period of lucerne, PM and BM treatments augment the average moisture content of the soil layer of 0–120 cm by 31.19% and 24.03% compared to the FP treatment, respectively. In the soil layer of 0–40 cm, PM and BM treatments abate the soil moisture content of the ridges by an average of 19.29% and 7.89% compared to that in the ditches, respectively. In the soil layer of 40–120 cm, PM and BM treatments elevate the soil moisture content of the ridges by 4.40% and 4.65% on average compared to that in the ditches, respectively. The average soil temperature in a soil layer of 5–25 cm shows PM > BM > FP. In contrast with the FP treatment, PM and BM treatments increase the soil temperature of the ridges by an average of 1.87 °C and 0.96 °C and decrease that of the ditches by an average of 0.47 °C and 0.46 °C, respectively. After two years of planting, the three cultivation patterns all promote the soil nutrient content. Compared to the FP treatment, PM and BM treatments increase the organic matter content by 9.94% and 19.94%, respectively. (2) Ridge tillage with film mulching can evidently stimulate the growth of lucerne and enhance yield and quality. Compared to the FP treatment, PM and BM treatments enhance plant height by an average of 15.37% and 4.04%, stem diameter by an average of 34.14% and 14.58%, yield by an average of 21.20% and 14.77%, crude protein content by an average of 13.47% and 7.68%, and relative feed value by an average of 8.71% and 4.41%, respectively. (3) During the two-year growing period, the irrigation amount of lucerne was 508.60–615.30 mm, and the evapotranspiration was 563.70–761.80 mm. Compared to the FP treatment, PM and BM treatments hoist water use efficiency by an average of 43.50% and 17.56%, nitrogen partial factor productivity by an average of 21.20% and 15.22%, and net income by an average of 14.78% and 11.05%, respectively. In summary, in ridge tillage, both ordinary film mulching and biodegradable film mulching can create a favorable soil environment for lucerne growth and heighten production effect. The former has a better effect on advancing the lucerne production effect, and the latter exhibits superior performance in improving soil fertility.

Assessment of Yield and Quality of Eggplant (Solanum melongena L.) Fruits Improved by Biodegradable Mulching Film in Two Different Regions of Southern Italy

Low-density polyethylene (LDPE) mulching films have an important function in crop cultivation; at the end of their life, however, their removal and disposal become both an economic and environmental problem. One possible alternative to low-density polyethylene (LDPE) mulch is provided by certified soil-biodegradable mulch films, such as those produced by Novamont and commercially available under the trade name MaterBi®. MaterBi is a biodegradable thermoplastic material made with starch and a biodegradable copolyester based on proprietary technology. In this study, we compared two biodegradable MaterBi®-based films (commercial and experimental films) with bare soil and a low-density polyethylene to evaluate their effect on yield and on a number of qualitative characteristics (organoleptic and nutraceutical composition) of eggplant fruits (cv Mirabelle F1) grown in two different regions in Southern Italy (Sicily and Campania). In our study, the use of biodegradable MaterBi® films improved not only yield and production parameters, such as the number and average weight of fruits, but also lipophilic and hydrophilic antioxidant activity and phenolic and ascorbic acid content. For many parameters, responses differed according to the cultivation environment and, in particular, the site’s pedoclimatic conditions. Our results suggest that biodegradable MaterBi®-based mulching films are a potentially valid alternative to traditional LDPEs, providing the production and quality benefits reported above and promoting environmental sustainability, thanks to their positive biodegradable properties.

Social interaction and recycling of waste mulch film: Understanding the impacts of communication channels

To control plastic pollution, it is imperative to encourage and facilitate waste mulch film (WMF) recycling by farmer cooperative members. We investigate the WMF recycling behavior of farmers in several randomly selected regions from the main vegetable-producing provinces in China. Propensity score matching is used to study the impacts of face-to-face, telephone, and social media communication on WMF recycling behavior of farmers. Our study shows that face-to-face communication is still the most important channel to promote farmers’ recycling behavior. Therefore, while it is more efficient to promote WMF recycling through social media in the Internet age, cooperative managers should not underestimate the role of face-to-face communication which is the preferred communication channel for many small farmers according to our analysis. Cooperative managers can better promote their members’ WMF recycling behavior through both social media and face-to-face communication.

Ridge-furrow film mulch with nitrogen fertilization improves grain yield of dryland maize by promoting root growth, plant nitrogen uptake and remobilization

Soil mulch has been widely applied to enhance crop yields in (semi-)arid and semi-humid regions on the globe. However, how different mulch practices influence root growth, plant nitrogen (N) uptake, remobilization and allocation remains unclear, especially under different N fertilization rates. A two-season (June–October in 2021 and 2022) field experiment was performed on dryland summer maize in a semi-humid but drought-prone region of northwest China. There were six mulch practices: flat cultivation without mulch (Flat), flat cultivation with straw mulch (Flat-Straw), flat cultivation with black film mulch (Flat-Film), flat cultivation with transparent film mulch (Flat-Trans), ridge-furrow cultivation with black film mulch on the ridge (Ridge-Film), ridge-furrow cultivation with transparent film mulch on the ridge (Ridge-Trans), and two N fertilization rates: 0 kg N ha−1 (N0) and 180 kg N ha−1 (N1). The results showed that film mulch significantly (p<0.05) improved root morphological parameters compared to Flat. Plant N uptake significantly (p<0.05) increased due to improved root growth under film and straw mulch, with grain N uptake increasing by 78.2% under Ridge-Film, 66.2% under Ridge-Trans and 39.6% under Flat-Film compared to Flat. The significant (p<0.01) increases in pre-anthesis N remobilization and post-anthesis N uptake under film and straw mulch compared to Flat achieved synergistic increases in grain yields. The contributions of total N remobilization to grain N dramatically increased by 31.2%, 27.5%, 17.0% and 11.2% under Ridge-Film, Ridge-Trans, Flat-Film and Flat-Trans compared to Flat, respectively. Meanwhile, film-mulched practices significantly (p<0.01) reduced soil nitrate-N residual due to improved plant N uptake, by 21.7% under Flat-Film, 16.9% under Flat-Trans, and 33.6% under Ridge-Film compared to Flat. The contributions of various mulch practices to grain yield ranked as Ridge-Film > Flat-Film > Ridge-Trans > Flat-Trans > Flat-Straw. The Ridge-Film with N fertilization significantly (p<0.05) increased N use efficiency, N agronomic efficiency, N recovery efficiency, N harvest index and grain yield by 10.8%, 124.9%, 147.1%, 19.8% and 120.0% compared to FlatN0, respectively. The structural equation modeling indicated that the differences in post-silking N uptake and pre-silking N remobilization caused by different mulch practices and nitrogen rates could directly explain at least 48.0% and 52.0% of grain yield differences. The ridge-furrow cultivation with film mulch, especially black film mulch, along with 180 kg N ha−1 is favorable for improving grain yield and N use efficiency of dryland summer maize in the semi-humid but drought-prone region of northwest China.

Characterizing Microplastic Pollution and Microbial Community Status in Rice Paddy Soils Across Varied Environmental Settings in Songjiang, Shanghai: An Analysis of Morpho-Chemical Characteristics

Microplastic (MP) pollution poses a huge threat to rice fields, but the distribution characteristics of MPs in farmlands of different types of areas are still uncertain. In this work, 24 samples from 12 rice fields of four different land-use types (Factory, highway, greenhouse/mulching and normal fields) were collected from Songjiang, Shanghai. From our selected sites, it was found that MP abundances were in the range of 233.33- 173.33 particles/kg in rhizosphere and bulk soil. MP distribution results showed that over 40% of particles were less than 1 mm and MP sizes ranging between 1 and 5 mm represented the greatest proportion. According to our study, MP in rhizosphere soil has the highest abundance (233.33 ± 57.73 particles/kg) than bulk soil. The particle shape classified as fragment (with edges and angular) was the most frequent shape found near factory areas, with an abundance of approximately 37.10%. Copolymers of polypropylene- polyethylene (PP/PE) at 24.30% were the most abundant polymers in rice lands in both bulk and rhizosphere soils; following is polystyrene (PS) at 21.40%, respectively. Most of the particles found in soils were white. Statistical analyses showed that fields near factories and fields where plastic mulching (mulch film and greenhouse crops) was used had a significantly higher particle abundance for bulk and rhizosphere soils, hence identifying plastic mulching as a major contributor to MP pollution in paddy soils. In industrial areas, MP can also be generated by released waste or by air. Microbial studies in rice roots, rhizosphere soil, and bulk soil show variation in the abundance of different species and genera. The dominant bacterial phyla in rice roots are Proteobacteria, Actinobacteriota, Firmicutes, and Bacteroidota. These microbes have been observed and can be impacted by the presence of MPs. Rhizosphere soil and bulk soil have an abundance of Chloroflexi, Actinobacteriota, Proteobacteria, Firmicutes, and Acidobacteriota. The specific effects on the microbial community structure depend on factors like MP type, concentration, and exposure duration. As our study was field-based, the significant effect of a specific type or concentration of MP was difficult to identify. Variation analyses of MP characteristics revealed that paddy lands were more likely to contain fragment shapes and large MP particles (1-5 mm). Also, rhizosphere soils were likely to contain fragment shapes and pony-size MPs (0.02-0.2 mm). Differences among rice fields may depend on various reasons, such as using slow- release fertilizers, mulching plastic application, irrigation, atmospheric fallout, etc. This study provides some proper evidence about the characteristics of MP pollution in rice fields of Songjiang and explores some probable conditions and predominant MP sources in rice fields.

Biodegradable mulching materials for agriculture: technology and environmental safety

Soil mulching is a common agricultural technique that reduces moisture loss, suppresses weeds, regulates soil temperature, and generally increases yield. Traditionally, low-density polyethylene is used for these purposes due to its mechanical and barrier properties, resistance to all forms of degradation, simple processing of cover soil, and low cost. However, using polyethylene has several artificial and environmental risks associated with difficult biodegradability, the difficulty of its removal after the harvest cycle, and final disposal. Therefore, there is great interest in the use of biodegradable mulch films. Two groups of materials most suitable for producing biodegradable coatings are polysaccharides of natural origin and biopolymers of synthetic origin. Technological methods for producing biopolymers from raw natural material by extraction from biomass and chemical or biotechnological methods are analyzed. Data are presented on the potential of biodegradable mulch materials of natural origin, films based on polysaccharides, synthetic polymers, and those applied as a solution for possible replacement of traditional mulch materials. A comparison was made of the compositions of biodegradable coatings, their properties, and their effects when used. The prospects and ways of introducing biodegradable film materials into agricultural practice are summarized.

Study of Humic Acid Organic Liquid Mulching Film on Promoting Green Agriculture Development

Mulching film is an important measure to promote agricultural production income and increase, the current widely used plastic mulching film has high stability, difficult to decompose, resulting in "agricultural white pollution", the development and application of degradable mulching film has become a solution. This case focuses on the study of organic multifunctional liquid mulching film with humic acid as the main raw material, which plays a unique role in promoting biological activity and soil improvement, the application of "liquid" spray film, the integration of fertilizer, pesticides, mulching film in one multi-functional comprehensive effect, to clarify its functional characteristics, alternative feasibility and the promotion of green agricultural development, and put forward the existing problems and countermeasures. This paper provides technical support and practical demonstration for the elimination of exogenous pollutants in farmland, and looks forward to the broad application prospects of this liquid mulch film in environmental protection and other aspects.

A comprehensive evaluation of influencing factors of neonicotinoid insecticides (NEOs) in farmland soils across China: First focus on film mulching

Neonicotinoid insecticide (NEO) residues in agricultural soils have concerning and adverse effects on agroecosystems. Previous studies on the effects of farmland type on NEOs are limited to comparing greenhouses with open fields. On the other hand, both NEOs and microplastics (MPs) are commonly found in agricultural fields, but their co-occurrence characteristics under realistic fields have not been reported. This study grouped farmlands into three types according to the covering degree of the film, collected 391 soil samples in mainland China, and found significant differences in NEO residues in the soils of the three different farmlands, with greenhouse having the highest NEO residue, followed by farmland with film mulching and farmland without film mulching (both open fields). Furthermore, this study found that MPs were significantly and positively correlated with NEOs. As far as we know this is the first report to disclose the association of film mulching and MPs with NEOs under realistic fields. Moreover, multiple linear regression and random forest models were used to comprehensively evaluate the factors influencing NEOs (including climatic, soil, and agricultural indicators). The results indicated that the random forest model was more reliable, with MPs, farmland type, and total nitrogen having higher relative contributions.

Highly dispersed biochar as a sustainable filler for enhancing mechanical performance and biodegradation of polybutylene succinate

AbstractSustainability has become increasingly important as environmental issues continue to rise. Biodegradable polymers offer a sustainable solution as they use biomass. In this study, biochar (BC) prepared by the pyrolysis of biomass was compounded with polybutylene succinate (PBS) to enhance its Young's modulus, and the residual BC was shown to amend the soil, following degradation. The incorporation of biochar into the PBS matrix is strategically achieved through a BC with treatment involving an aprotic polar solvent. This process not only reduces the size of the biochar particles but also ensures their uniform dispersion within the PBS matrix. As a result, a remarkable 2.5‐fold increase in Young's modulus is observed, reaching an impressive 571.04 MPa, compared with the baseline Young's modulus of neat PBS, which stands at 220.92 MPa. Interestingly, the degradation rate of the resulting composites was comparable to that of neat PBS despite the decrease in the number of potential hydrolysis sites owing to the increased Young's modulus of the PBS/BC composite. These sustainable composite exhibited properties different from those of conventional PBS and is expected to be used in potentially novel applications toward environmental sustainability, such as in agricultural mulch films or electronic printing.

Effects of Conventional Non-Biodegradable Film-Derived Microplastics and New Biodegradable Film-Derived Microplastics on Soil Properties and Microorganisms after Entering Sub-Surface Soil

Plastic film mulching, widely used in agriculture, leads to microplastic (MP) pollution in soils. While biodegradable polybutylene adipate terephthalate (PBAT) films may offer a solution, their impacts on subsurface soils and microorganisms remain unclear. To investigate the effects of conventional non-biodegradable polyethylene (PE) and biodegradable PBAT MPs on the properties of sub-surface soils and microbial communities, MPs were added at varying doses in a field experiment and incubated for 160 days. Physicochemical characteristics, nutrient dynamics, and microbial composition, diversity, and networks of soils were analyzed using standard techniques and 16S rRNA/ITS gene sequencing. Correlations between soil properties and microbes were assessed. Both MP types significantly altered soil characteristics, with PBAT-MP elevating pH and the levels of available phosphorus and potassium more than PE-MP. Microbial composition shifts occurred, with low-addition PBAT-MP promoting plastic-degrading genera. The assessment of α/β-diversity indicated that PBAT-MP predominantly influenced fungi while PE-MP impacted bacteria. An examination of microbial co-occurrence networks highlighted that PE-MP primarily disrupted fungal interactions, whereas PBAT-MP streamlined network complexity. Correlation analyses revealed that PBAT-MP promoted fungal diversity/network resilience correlating to nutrients. PE-MP and PBAT-MP significantly altered native soil/microbe relationships. PBAT-MP may exert greater, yet unknown, impacts over time through its biodegradation into newer and smaller fragments. Future research needs to integrate multi-omics and stable isotope science to elucidate the deep mechanistic impacts of degraded film-derived MPs on microbial ecological functions and biogeochemical cycles. Attention should also be paid to the long-term accumulation/transport of MPs in agricultural soils. Overall, this work deepens the impact and understanding of MPs from plastic film on sub-surface soil ecology. Furthermore, it provides a theoretical foundation for managing ‘white pollution’ in the film-covered farmlands of arid and semi-arid regions in China.

Modification of polyvinyl alcohol with 2-hydroxypropionic acid and cross-linking with glutaraldehyde for the preparation of biodegradable mulch paper and its properties

Abstract The preparation of biodegradable mulch film with paper-based materials has become a significant focus in mulch film development due to the serious pollution caused by plastic mulch film. This study utilized the esterification cross-linking reaction of LA, PVA, and GA to coat the surface of paper as the substrate. FTIR, TGA, XRD, SEM, tensile testing, and oxygen, water vapor barrier performance tests were performed. The optimal conditions for film preparation were determined to be a 10 % PVA aqueous solution, 5 % GA content, and a PVA/LA/GA ratio of 1:2:1. The resulting film paper exhibited a dry strength of 6.52 kN/m, a wet strength of 0.23 kN/m, a tearing degree of 969.35 mN, a Cobb value of 12.04 g/m2, a water vapor transmission rate of 573.27 g m−2 24 h−1, and an oxygen transmission rate of 7.373 cm3 m−2 24 h−1. After a 6-week landfill degradation test, the film showed a degradation rate of 25.3 %, while still maintaining a tensile strength of 1.89 kN/m. Field application tests in greenhouses confirmed that the film paper facilitated the growth of strawberry, its mechanical and barrier properties suitable for a biodegradable paper mulch.

Fabrication of modified lignin-based liquid mulching film and its potential application

Abstract Liquid mulching film is an emerging film material to replace the traditional plastic film, which causes wide public concern. In this study, a graft copolymer (LS-AA) was synthesized from sodium lignosulfonate (LS) by free radical polymerization, which was added as enhancer to the cationic starch (CS) solutions to obtain the CLA based film. The grafting conditions was optimized by response surface methodology (RSM) for the preparation of LS-AA, after that the LS-AA was characterized by FTIR, XRD, and TG. The highest grafting rate was obtained under the reaction conditions of 80 °C for 2.6 h with the mass ratio of monomer and LS of 5.5/5 at initiator dosage of 1 %. The fabricated liquid mulching film with addition of LS-AA showed outstanding anti-ultraviolet, biodegradation, anti-erosion, which provided theoretical base and practical references for popularizing and application of liquid mulching film in the dust prevention and sand fixation.

Effects of the Plastic Mulching System and Fertilizer Application on the Yield of Tartary Buckwheat (Fagopyrum tataricum) and Water Consumption Characteristics in a Semi-arid Area

Although plastic film mulching is commonly utilized to enhance crop water use efficiency (WUE) in semi-arid areas, the combined effect of plastic film mulching and fertilizer application on Tartary buckwheat yield is still unknown. To address this gap, a four-year field experiment was conducted from 2018 to 2021 to investigate the effect of plastic film mulching and fertilizers on the soil water storage, plant growth, yield, and WUE of Tartary buckwheat in semi-arid environments. The treatments comprised traditional planting without fertilizer (TNF), traditional planting with fertilizer application (N–P2O5–K2O: 40–30–20 kg ha−1) (TF), plastic film mulching with fertilizer application (N–P2O5–K2O: 40–30–20 kg ha−1) (MF), and plastic film mulching without fertilizer (MNF). The results indicated that MF treatment significantly increased leaf area index and SPAD values compared to the other treatments. The yield of Tartary buckwheat under the film mulching increased by 23.3% in comparison to no-mulching treatments, and under fertilizer application it increased by 18.2% compared to no fertilizer. WUE under film mulching exhibited an increase of 3.1% in 2018, 34.9% in 2019, 45.5% in 2020, and 34.6% in 2021, respectively, compared to no mulching. The impact of film mulching on WUE was more significant in years with lower precipitation compared to those with normal or higher precipitation levels. Overall, MF significantly enhanced both the yield and WUE of Tartary buckwheat. This approach proved to be an effective strategy for bolstering drought-resistant yield and optimizing resource efficiency in Tartary buckwheat cultivation in semi-arid regions. Moreover, the positive effects of plastic mulching and fertilizer application on grain yield and water use efficiency were more pronounced in drier years.

Exploring the potential of earthworm gut bacteria for plastic degradation

The use of plastic mulch films in agriculture leads to the inevitable accumulation of plastic debris in soils. Here, we explored the potential of earthworm gut-inhabiting bacterial strains (Mycobacterium vanbaalenii (MV), Rhodococcus jostii (RJ), Streptomyces fulvissimus (SF), Bacillus simplex (BS), and Sporosarcina globispora (SG) to degrade plastic films (⌀ = 15 mm) made from commonly used polymers: low-density polyethylene film (LDPE-f), polylactic acid (PLA-f), polybutylene adipate terephthalate film (PBAT-f), and a commercial biodegradable mulch film, Bionov-B® (composed of Mater-Bi, a feedstock with PBAT, PLA and other chemical compounds). A 180-day experiment was conducted at room temperature (x̄ =19.4 °C) for different strain–plastic combinations under a low carbon media (0.1× tryptic soy broth). Results showed that the tested strain–plastic combinations did not facilitate the degradation of LDPE-f (treated with RJ and SF), PBAT-f (treated with BS and SG), and Bionov-B (treated with BS, MV, and SG). However, incubating PLA-f with SF triggered a reduction in the molecular weights and an increase in crystallinity. Therefore, we used PLA-f as model plastic to study the influence of temperature (“room temperature” & “30 °C”), carbon source (“carbon-free” & “low carbon supply”), and strain interactions (“single strains” & “strain mixtures”) on PLA degradation. SF and SF + RJ treatments significantly fostered PLA degradation under 30 °C in a low-carbon media. PLA-f did not show any degradation in carbon-free media treatments. The competition between different strains in the same system likely hindered the performance of PLA-degrading strains. A positive correlation between the final pH of culture media and PLA-f weight loss was observed, which might reflect the pH-dependent hydrolysis mechanism of PLA. Our results situate SF and its co-culture with RJ strains as possible accelerators of PLA degradation in temperatures below PLA glass transition temperature (Tg). Further studies are needed to test the bioremediation feasibility in soils.

Unperforated film-covered planting contributes to improved film recovery rates and foxtail millet grain yields in sandy soils

Plastic film mulching improves the soil water content and temperature and, thus, contributes to enhanced grain yield in arid and semi-arid areas, such as Northwest China. However, in traditional film-covering methods, plastic films are difficult to recycle, causing environmental issues. Therefore, developing cultivation methods with enhanced film recovery rates is important for sustainable agricultural development. Here, we evaluated how the planting method affected the soil temperature, water content, film recovery rate, and grain yield by applying the following three planting patterns to the traditional crop, foxtail millet, in 2021–2022: no plastic film mulching (NP), plastic film mulching (MP), and planting on the film edge (PFE); in the latter, holes were not punched in the film and crops were planted approximately 5 cm from the film edge. The results for 2021 showed that the biomass ranged from 27.69 g to 33.76 g per plant, and the biomass was increased by 21.9% and 3.2% in PFE compared with NP and MP, respectively. However, in 2022, the biomass increased in PFE by 52.5% and 17.7% compared with NP and MP, respectively. In 2021, the highest grain yield was observed in PFE (2480 kg/hm2), followed by MP (2470 kg/hm2) and NP (2343 kg/hm2); in 2022, a significantly higher grain yield was observed in PFE than that in MP and NP. Although the soil temperature increased in PFE, it was not as high as in MP. The relatively higher soil temperature increased the root growth process, stimulated the production of root exudates (acetic acid and citric acid), and increased the soil enzyme (sucrase and urease) activity. Increases in organic acids and soil enzymes assisted in the decomposition of soil organic matter and induced relatively higher levels of available nutrients, such as nitrogen and phosphorus, and the higher root reuse rates contributed to higher grain yields. In addition, fewer holes were punched in the film of the PFE model, which improved film recovery, and the recovery rate of PFE was higher than that of MP. These results indicate that the proposed unperforated film-covered planting pattern is suitable for millet production in sandy soil.

Long‐term straw mulching alleviates microbial nutrient limitations and increases carbon‐use efficiency within aggregates

AbstractLong‐term straw mulching was known to change soil nutrient content, aggregate distribution and extracellular enzyme activities. However, the impact of long‐term straw mulching on microbial nutrient limitations and carbon‐use efficiency (CUEst) within aggregates remains unclear. To fill the gap, we conducted a 10‐year field experiment in a semi‐arid region and used an ecoenzymatic stoichiometry model to quantify microbial resource limitations in soil aggregates under long‐term mulching. We studied the effects of two mulching measures (plastic film mulching [FM] and straw mulching [SM], with no mulching as the control [CK]) on the nutrient content and limitations within aggregates. The results show that compared with FM, SM increased the proportion of aggregates to larger &gt;2 mm and decreased the proportion of aggregates in the 2–0.25 mm classes. Additionally, FM resulted in carbon (C) and phosphorus (P) limitations in the soil, particularly in the &gt;2 mm class, while SM alleviated these constraints. This effect was primarily attributed to the increase in soil organic carbon (SOC) and microbial biomass carbon content (Cm), especially the enhanced carbon content associated with larger aggregates (&gt;2 mm) and the increased activities of carbon–nitrogen (C–N)‐acquiring enzymes. SM also resulted in high CUEst by influencing microbial P limitation. Random forest analysis indicates that soil abiotic factors, particularly SOC and total nitrogen (TN), were the main drivers of microbial resource limitations within the aggregates. These findings suggest that the mulching material determines the development of soil aggregates and resource allocation within these aggregates. Thus, the study provides valuable insights for formulating effective carbon management strategies in semi‐arid regions.