In-field degradation of soil-biodegradable plastic mulch films in a Mediterranean climate

Griffin‐LaHue, Deirdre; Ghimire, Shuresh; Yu, Yingxue; Scheenstra, Edward; Miles, Carol A.; Flury, Markus

doi:10.1016/j.scitotenv.2021.150238

Cited by 60 publications

(29 citation statements)

References 24 publications

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“…Biodegradable mulches (BDMs) may represent an effective green alternative to reduce plastic residue risks in farmland [ 1 , 2 ]. These kinds of materials have shown disintegration and mineralization comparable with paper and leaves and compliance with the European standard EN 17033 [ 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

Degradability and Properties of PBAT-Based Biodegradable Mulch Films in Field and Their Effects on Cotton Planting

et al. 2022

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Biodegradable mulches (BDMs) are considered promising alternative green materials to achieve the substitution of polythene (PE) films to reduce plastic pollution. However, whether the BDMs are sufficiently effective to promote cotton production as PE film is a controversial topic. In this study, laboratory determination and field experiments were conducted with one pure Poly(butylene adipate-co-terephthalate) (PBAT) film (BDM), two commercial PBAT-based films (BDM1 and BDM2), and one PE film to (ⅰ) compare the degradation behavior, morphology, and property changes during field application, and (ⅱ) reveal their effects on biomass accumulation and cotton yield. Degradation behavior, degradation rate, structure, thermal stability, crystallinity, and molecular weight changes of the films before and after mulching were investigated and characterized. Water vapor transmission rate and mechanical properties of the films and the effects these on soil temperature, crop growth, and cotton yield were discussed. Results show that the three PBAT-based mulch films gradually degraded during mulching. The molecular weight, thermal stability, and crystallinity of BDM1 and BDM2 decreased. Interestingly, BDM showed the opposite characteristics, but the degradation degree was greatest at harvest. PE film showed no significant changes in its microscopic appearance, thermal performance, or properties. These PBAT-based films were positively correlated with the complete coverage period of the films. In-depth studies focused on BDMs with a longer mulching period must be developed to promote the substitution of BDMs into PE to reduce the residual mulch pollution in cotton fields.

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Section: Introductionmentioning

confidence: 99%

Degradability and Properties of PBAT-Based Biodegradable Mulch Films in Field and Their Effects on Cotton Planting

et al. 2022

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“…The biodegradation rates of the three mulch films tested were assessed by their 'weight loss' and 'surface area loss', which are not equivalent to their actual biodegradation, but can be considered indirect indicators of biodegradation (Rudnik and Briassoulis, 2011;Sintim et al, 2020;Griffin-LaHue et al, 2022). Both weight and surface area loss are suitable for open-field trials when the biodegradability of the mulch films has already been shown in the laboratory, following international standards (Francioni et al, 2021).…”

Section: Estimation Of Film Biodegradation By Indirect Indicatorsmentioning

confidence: 99%

“…Under open-field conditions, both abiotic and biotic degradation phases are key to the fate of biodegradable mulch films (Sintim et al, 2020;Griffin-LaHue et al, 2022). When a crop is still in place, the mulch films are expected to moderate soil temperature, water content and weed pressure, and the actions of soil biodegraders are expected to be low because the mulch films are predominantly outside the soil.…”

Section: Mulch Film Degradation As Affected By Environmental Factorsmentioning

confidence: 99%

“…Moreover, even the different crops and the related agronomic practices required during their growth can have key roles during both mulch film weathering (i.e., shadowing) and after their incorporation into the soil (e.g., activity of microorganisms, root exudates). These are important aspects that need to be taken into consideration, especially because soil-biodegradable mulch films are designed to be used and then buried under open-field conditions and not in the laboratory (Yang et al, 2020;Francioni et al, 2021;Griffin-LaHue et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Soil refinement accelerates in-field degradation rates of soil-biodegradable mulch films

et al. 2022

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Soil-biodegradable mulch films are a promising solution to replace conventional polyethylene-based mulch films, the use of which has led to negative environmental impacts. Soil-biodegradable mulch films are specifically designed to be incorporated into the soil at the end of the cropping cycle, and are expected to be biodegraded by soil microorganisms. The biodegradability of such products must be tested under laboratory-controlled conditions following international standards, although these can fail to represent real environmental conditions where mulch films are used. The objective of this study was to evaluate the effects of soil refinement on the degradation rates of three different commercial soil-biodegradable mulch films after their incorporation into the soil. The hypotheses were that: (i) soil refinement (i.e., ploughing followed by grubbing) creates more favourable conditions for film biodegradation compared to ploughing alone; and (ii) different mulch films show different degradation rates. An open-field completely randomised design was applied to test the effects of soil refinement by ploughing to 0.35 m depth without and with subsequent grubbing to 0.15 m depth twice. Three commercially available soil-biodegradable mulch films were sampled in 2020 (i.e., two Mater-bi-based, one Ecovio-based) at the end of a zucchini growing season (~3 months) when films were still lying above ground, and were later buried at 0.2 m depth inside mesh bags. Biodegradation rates of the sampled films were assessed with the indirect indicators of film weight loss and surface area loss at ~2-month intervals over 314 days. The results showed that soil refinement significantly accelerated degradation of the three tested mulch films by 14% and 17% according to the loss of weight and surface area indicators, respectively. One Mater-bi-based film showed higher degradation rates compared to the other two films. Future studies are needed to quantify the time needed for these different mulch films to be completely biodegraded. Such studies should be carried out following standards for laboratory incubation and/or in-field quantification of residual polymers in the soil over time. Highlights- Degradation rates of three biodegradable mulch films were evaluated in the open-field.- Soil refinement accelerates the degradation of film weight (14%) and surface (17%).- Highest degradation rates were observed for one Mater-bi-based film.- Fastest degradation rates were observed in spring for all the tested films.- Weight and surface area loss indicators showed positive relationship.

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“…Given the results, it was predicted that it will take 21-58 months for the soil-biodegradable mulches to attain 90% degradation. This study shows that while laboratory-based assays are necessary, they may not represent the degradability of soil-biodegradable mulches after soil incorporation at a field site (Griffin-LaHue et al, 2022). Additional field test protocols are needed to evaluate soil-biodegradable mulch degradation under diverse soil and environmental conditions to provide site-specific time estimates for complete in-soil degradation.…”

Section: Alternative To Polyethylene Mulch-soil-biodegradable Plastic...mentioning

confidence: 99%

End-of-Life Management Options for Agricultural Mulch Films in the United States—A Review

Madrid

Wortman

Hayes

et al. 2022

Front. Sustain. Food Syst.

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Polyethylene plastic mulches are widely used in specialty cropping systems in the United States due to the horticultural benefits they provide. However, polyethylene mulch is reapplied seasonally, generating large volumes of plastic waste that contribute to plastic pollution concerns. This review synthesizes scientific and industry findings to provide a state of current end-of-life options of polyethylene mulch in the United States and identifies opportunities that can improve plastic waste management with a special emphasis on soil-biodegradable plastic mulches. Major points discussed are: (1) polyethylene mulch use in specialty cropping systems, (2) economic, environmental and waste management impacts of polyethylene mulch use, (3) current common end-of-life pathways of used polyethylene mulch, (4) use of soil-biodegradable plastic mulch as an alternative to reduce the amount of plastic waste in the environment and offset the negative impacts associated with residual non-degradable plastics, (5) socioeconomic factors that reduce the adoption of soil-biodegradable plastic mulch, and (6) limitations of soil-biodegradable mulch. The results of this review conclude that recycling and upcycling of used polyethylene mulch can be a more sustainable disposal option, however cleaning and decontaminating used polyethylene mulch is costly and commercial technology is often not accessible nor economically viable in many regions in the current economic and political situation. To make recycling a viable pathway in the future, research and policy developments are necessary to refine and encourage recycling. Soil-biodegradable plastic mulches can offer an additional opportunity to help address these limitations, but they are not permitted in organic agriculture in the United States. Further studies are necessary to address the current knowledge gaps and gain a better understanding of the factors influencing the degradation of soil-biodegradable mulches under diverse field conditions. Improved end-of-life strategies should continue to be pursued that balance sustainable use of plastic mulch while minimizing environmental risks.

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In-field degradation of soil-biodegradable plastic mulch films in a Mediterranean climate

Cited by 60 publications

References 24 publications

Degradability and Properties of PBAT-Based Biodegradable Mulch Films in Field and Their Effects on Cotton Planting

Degradability and Properties of PBAT-Based Biodegradable Mulch Films in Field and Their Effects on Cotton Planting

Soil refinement accelerates in-field degradation rates of soil-biodegradable mulch films

End-of-Life Management Options for Agricultural Mulch Films in the United States—A Review

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