Introduction

Mulch films directly applied to the soil provide insulation against solar radiation on the surface, increase crop production by reducing weed occurrence and pest incidence, and preserve soil moisture levels and temperatures (Dıaz-Perez et al. 2004; Kasirajan and Ngouajia 2012; Snyder et al. 2015; Steinmetz et al. 2016; Mansoor et al. 2022). Agricultural polyethylene (PE) plastic mulch with a low-density film has been widely used for crop production worldwide since the 1950s owing to improvements in mechanical strength, efficiency, and economic value (Dıaz-Perez et al. 2004; Kasirajan and Ngouajia 2012; Snyder et al. 2015; Steinmetz et al. 2016; Mansoor et al. 2022). However, the removal and waste of PE films after cultivation have led to environmental contamination and decreased recycling of fossil-derived plastics. Biodegradable (BD) film mulches were commercially introduced in 2006, are mainly classified into petroleum-based polymers, specfically, polybutylene adipate-co-terephthalate (PBAT), polybutylene succinate (PBS), and polyglycolic acid (PGA), as well as renewable-resource-based materials, specfically, starch, cellulose, and polylactic acid (PLA); these materials decompose rapidly into CO₂ and water after being incorporated into the soils (Kasirajan and Ngouajia 2012; Wang et al. 2014; Steinmetz et al. 2016; Bandopadhyay et al. 2018; Yang et al. 2021; Mansoor et al. 2022; Wang et al. 2022; Zhang et al. 2022; Jung et al. 2023; Campanale et al. 2024; Kim et al. 2024), but little scientific information is available regarding the time required for their decomposition in soil (Zhou et al. 2023).

Crop cultivation with BD film mulches could contribute to achieving net-zero emissions by 2050 and retard climate change under the global roadmap of the United Nations (Kasirajan and Ngouajia 2012; Steinmetz et al. 2016; Bandopadhyay et al. 2018; Mansoor et al. 2022; Jung et al. 2023; Campanale et al. 2024). Recent reviews published of BD film mulching have emphasized the feasibility or efficacy assessments of sustainable solutions, whereas few reports are associated with the impacts of incomplete biodegradation and residue after the migration of BD films into the soil (Zhang et al. 2022; Huang et al. 2023). The application of BD mulch showed similar positive agronomic effects, improving the physical properties of the soil with rich microbial diversity and enhancing microclimatic conditions owing to less contamination, high air permeability, and drainage of agricultural lands (Kasirajan and Ngouajia 2012; Martín-Closas et al. 2017; Bandopadhyay et al. 2018; Sintim et al. 2019). However, BD-microplastic-derived carbon (C) in soil can accumulate owing to high microbial activity and can cause high C and nitrogen (N) ratios, possibly contributing to reduced nutrient availability for roots and inhibiting crop growth. In relation to this observations from existing short-term experiments are limited and the results of the effects of long-term biodegradable film mulch on vegetable crops are inconsistent (Volova et al. 2017; Boots et al. 2019; Zhang et al. 2022; Huang et al. 2023; Park et al. 2024).

Chili peppers (Capsicum annuum L.) as a type of seasoned vegetable are extensively cultivated, with production of approximately 61,665 tons in an overall field area of 27,132 ha in South Korea in 2023 (KOSTAT 2024). Chili peppers are cultivated in warm weather areas from April to September with PE film mulching as protection against the high amount of rainfall and to mitigate the occurrence of pests and weeds, thereby increasing pepper yields (Lee et al. 2024). Applications of BD film mulch with optimum degradation rates showed similar pepper growth and fruit productivity outcomes as well as high efficiency in terms of labor and costs, similar to the results when using PE films (Jin et al. 2024), which may be more suitable for summer crop production (Yin et al. 2019). However, a decline in fruit yield was observed in pepper fields mulched with BD film with rapid degradation rates owing to the lower resistance, plasticity, and high nutsedge density later in the season (Moore and Wszelaki 2019). Accordingly, growers must select BD films depending on the local climate, crop growth characteristics, weed density, and film resources considering the components, thickness, and chemical structure (Campanale et al. 2024). BD mulch films can be directly incorporated into soil and are expected to disintegrate over time without requiring specific post-harvest handling, thus shortening the fallow period for crop rotation with winter crops, such as onion (Allium cepa L.) (Campanale et al. 2024). This process has scarcely been studied for a rotation field mulched with BD films, with no scientific papers published on the topic of pepper-onion rotation. Therefore, the present study was conducted to evaluate the effects of BD films potentially remaining through soil tillage following pre-pepper cultivation on stable and balanced soil mineral nutrition and subsequent onion growth outcomes and to investigate the biodegradation of microplastics derived from BD mulch after the completion of one crop rotation cycle.

Materials and Methods

Field environment

Crop rotation of two crops, specifically chili pepper followed by onion, across a sequence of growing seasons was conducted in a farmhouse field characterized as a mixture of silt loam in Gumi-si, South Korea (36° N, 128° E). The experimental plots were supplied with 6,000 kg of organic manure compost (30% of organic matter; 66% poultry manure compost, 26% mushroom waste medium, 3% dolomitic limestone, and 5% coffee grounds; Kumnong Fertilizer Co., Ltd., Seongju, South Korea) per hectare (ha) to enhance soil restoration before the transplantation of both crops (RDA 2017; RDA 2021; Jung et al. 2023; Park et al. 2024). A compound fertilizer (600 kg ha^-1; N-P₂O₅-K₂O-MgO-B:13-6-8+2+0.2, Chobi Co., Ltd., Seoul, South Korea) was then applied with the nutrient sources recommended for growing peppers and onions (RDA 2017; RDA 2021; Jung et al. 2023; Park et al. 2024). The experimental layout included 15 blocks with each block (plot) of 100 × 310-cm. The ‘Choteukgup’ pepper seedlings used here were obtained from the National Agricultural Cooperative Federation (Gumi, Korea) and were transplanted as the first crop in each plot with the traditional planting density on April 30 of 2023 (0 days after transplanting, 0 DAT) (RDA 2017; RDA 2021), with harvesting conducted on September 30 of 2023 (150 DAT). In addition, 60 kg of 3.0% terbufos soil insecticide (Counter, FarmHannong Co., Ltd., Seoul, South Korea) and 60 kg of tebuconazole 0.5% + thifluzamide 1.0% fungicide (Gyunhaekyongsa, Kyungnong Co., Ltd., Seoul, South Korea) were sprayed onto the soil to prevent soil-borne insects and diseases and were subsequently incorporated into conventional tillage to prepare the experimental plots before the transplanting of both rotated crops. A trickle irrigation system was applied to each crop using small plastic tubes if the soil became extremely dry.

After the harvesting of the peppers, the experimental plots were cultivated to a depth of approximately 10 cm using a cultivator and left unused to allow for a fallow period of 30 days. Subsequently, ‘Katamaru’ onion seedlings were obtained from Hyesung Seed Company (Cheonan, Korea) and were transplanted with the traditional planting density on October 30, 2023, at 0 DAT, with mulching again conducted in the same plots where the peppers were cultivated. The onions were harvested on May 30, 2024, at 210 DAT. Water, nutrients, and pest control were managed similarly to those during the previous pepper cultivation period.

Treatments

Five treatments were employed: non-mulching (NM), low-density black PE film (Samdong Co., Ltd., Cheonan, South Korea) mulching, and three BD-film mulching types, referred to as F film primarily consisting of PBAT and PLA (I. Co., Ltd., Ansan, South Korea), H film consisting of PBAT+PLA (S. Co., Ltd., Pocheon, South Korea), and E film made using PLA+starch (G. Co., Ltd., Icheon, South Korea) (Jung et al. 2023; Kim et al. 2024; Park et al. 2024). These treatments are commonly used for field crops in South Korea, with the treatment used in the same area for rotational crops across a sequence of growing seasons. Hoeing and hand pulling were used to control weeds in the NM plots until 90 days before the harvesting of each crop. The F-, H-, and E-BD films had thicknesses and densities of 0.015 mm and 1.73 mg·cm^-2, 0.015 mm and 1.85 mg·cm^-2, and 0.020 mm and 2.11 mg·cm^-2, respectively.

Film measurements

A piece of cut film (210 × 297 mm) was placed on the soil surface in each treatment plot to assess the maintenance of the weight of the films that remained over the time periods at 30-day intervals from 0 to 150 DAT in the pepper field, and from 0 to 210 DAT in the onion field (Lim et al. 2016; Jung et al. 2023; Park et al. 2024). A digital illuminance light meter (Hioki Co., Ltd., Tokyo, Japan) was used to measure the light inside and outside of the film on each treatment plot, reading the illuminance values between 13:00 and 15:00 during the growing season in both fields (Jung et al. 2023; Park et al. 2024). The light transmission rate was provided by calculating the relative percentage of the illuminance levels between the outside and inside of the film.

Soil measurements

Both the minimum and maximum values of the soil moisture and temperature were recorded hourly using a data logger (Efento Co., Ltd., Wroclaw, Poland) at a depth of 10 cm in the soil, approximately halfway on each treatment plot in the pepper field in August of 2023 and in the onion field in January and April of 2024.

A portable pH meter (HI-99121, Mettler Toledo CO., Jiangsu, China) and a soil conductivity tester (HI-2315, Hanna Co., Seoul, Korea) were used to monitor the pH and electrical conductivity (EC), respectively, at a soil depth of 10 cm at 30-day intervals from 0 to 150 DAT in the pepper field, and from 0 to 210 DAT in the onion field.

Soil samples were randomly collected using a soil auger at three points in each plot within a soil depth of 20 cm to determine the organic matter (OM) concentrations. We measured the NO₃-N, P₂O₅, K₂O, CaO, and MgO concentrations in the pepper field at 0 and 135 DAT in 2023 and in the onion field at 0 and 217 DAT in 2024 according to the standard soil nutrient analysis method of the agricultural science and technology department of the Rural Development Administration (RDA 2000).

Plant measurements

The stem height, diameter, and number of leaves were repeatedly measured for two pepper plants from each treatment plot based on soil plant analysis development (SPAD) values at 30-day intervals from 0 to 150 DAT, with the leaf FW also measured for two onion crops at 30-day intervals from 0 to 210 DAT. A leaf SPAD-502 portable meter was used to determine the amount of chlorophyll present in the pepper leaves (Minolta Co., Ltd., Tokyo, Japan).

Forty-five pepper fruit and six onion bulbs per treatment were harvested monthly to observe variations in the length, diameter, and average FW in pepper fruits from 90 to 150 DAT, and in onion bulbs at 0 to 210 DAT. The accumulated number of fruits and the corresponding FWs in the pepper crops were calculated per ha by combining all of the fruits produced at 90, 120, and 150 DAT. Large onion bulbs with diameters exceeding 100.0 mm were selected from the harvested bulbs at 210 DAT to determine the total yield of marketable bulbs per unit hectare.

Weeds in each treatment plot in the onion field were collected at 210 DAT to determine their fresh weight (FW) and dry weight (DW).

Biodegradation after crop rotation

The cut film (210 × 297 mm) was placed on the soil surface in each treatment plot or buried under 10 cm of soil after the harvesting of the onions for the completion of one crop rotation cycle. The microplastics collected at the soil depth in both cases were weighed to compare film degradation rates at 210, 240, and 270 DAT for the onions (Kim et al. 2024).

Statistical analysis

The experimental plot contained a total of 15 plots (three plots per treatment) in a randomized block design in each case to minimize environmental variability. A repeated-measures analysis of variance (ANOVA) was conducted to determine significant differences between the treatment means using Duncan’s multiple range test at the 5% probability level.

Results and Discussion

Climate conditions

The average and minimum air temperatures and cumulative precipitation rates were obtained from the annual climatological report of the Korea Meteorological Administration (KMA 2024) during the pepper cultivation period from April to September of 2023 and during the onion cultivation period from October of 2023 to May of 2024 (Fig. 1). The temperatures and humidity levels were high during the two-year growing season of pepper and onion rotation in the field compared with those over the last 30 years from 1993 to 2022. It is expected that this hot and humid climate would lead to further degradation of the surfaces of the BD films mulched in soil (Kasirajan and Ngouajio 2012; Yang et al. 2021; Somanthan et al. 2022).

Fig. 1.

Average and minimum air temperatures and cumulative precipitation levels averaged during the period from April to September of 1993–2022 and in 2023 in the pepper field (A) and averaged from October to May of 1993–2022 and 2023–2024 in the onion field (B).

Film degradation characteristics

The film weights for all BD films decreased in the pepper field from 90 to 150 DAT, in particular, a substantial decrease of nearly 30.0% was observed for the H and F films (Fig. 2A) owing to exposure to excessive temperatures and rainfall levels in summer. High weight maintenance of the E films (approximately 60.0%) was observed at 150 DAT, as these films had higher film thickness and density levels of 0.020 mm and 2.11 mg·cm^-2, respectively (Lee et al. 2009; Kasirajan and Ngouajia 2012; Abduwaiti et al. 2021). However, biodegradability among the BD films could not be clearly determined due to the limited information on the manufacturing process and the biodegradable polymer blends and composites used. The BD films degraded slightly in the same area under subsequent onion crop cultivation throughout the growing season (Fig. 2B). No consistent effect was observed with regard to the internal light transmission rates of any of the films mulched on both the pepper and onion fields over the entire period (Fig. 2C and 2D), a finding that indicates a lack of consistency in the reported effects of PE film mulch on light transmission (Liu et al. 2021). The light transmission rate of all mulching films decreased in the late season, specifically at 120 and 150 DAT, in the pepper field as excessive vegetative growth increased shelf-shading and light depletion (Formisano et al. 2022). This was in contrast to that in the onion field from 150 to 210 DAT owing to the approaching summer season and high exposure to solar radiation.

Fig. 2.

Weight maintenance (A and B), and light transmission (C and D) outcomes of polyethylene (PE) and biodegradable F, H, and E films mulched in the pepper-onion crop rotation field at different days after transplanting (DAT). Different letters adjacent to data points indicate a significant difference as determined by Duncan’s multiple-range test at p < 0.05.

Soil moisture and temperature

The minimum or maximum soil moisture levels fluctuated in all treated pepper plots, influenced by the ambient temperatures and humidity levels (Fig. 3A and 3B). The F film-mulched plots showed the lowest soil moisture levels of ‒44.0 and ‒47.0 kpa on August 15 and 16, respectively, presumably owing to high film biodegradability in summer with extreme rainfall and intense heat (Fig. 1). The maximum soil temperatures increased to 41.7°C in the NM plots on August 1, 2023, followed by 37.9°C in F film-mulched plots, which frequently showed the lowest soil minimum temperature (Fig. 3C and 3D).

Fig. 3.

Daily soil moisture contents (A and B) and temperature (C and D), as affected by non-mulching (NM), and polyethylene (PE) and biodegradable F, H, and E films mulched in the pepper field in August of 2023.

The minimum or maximum soil moisture level was between 0.0 and ‒10.0 kpa under wet conditions in all treated onion plots in January of 2024, decreasing remarkably in April, in particular for the F film-mulched plots (Fig. 4A-4D), which was also clearly observed in the pepper plots in August (Fig. 3A and 3B). The minimum and maximum soil temperatures in January and April did not vary in any of the treatment plots, except for the PE plots, wherein the maximum soil temperature increased to approximately 30.0°C (Fig. 4E-4H). This has been very commonly observed in many studies conducted in soils with higher temperatures and moisture contents with black plastic mulch in hot and arid weather conditions (Kasirajan and Ngouajia 2012; Steinmetz et al. 2016; Mansoor et al. 2022; Tofanelli and Wortman 2022). It is generally understood that PE mulch preserves heat at night (Tofanelli and Wortman 2022), whereas PE plots reduce minimum soil temperatures in April, presumably due to the reduced evaporation caused by the PE covering (Fig. 4F). The soil moisture content and temperature values of the NM plots were comparable to those of mulch treatment plots in both crop fields. The high heat capacity of available water in soil under irrigation in this study prevented variations in the soil moisture and temperature, which would have otherwise provided inconsistent results regarding the effects of mulch on soil temperature and moisture levels (Dıaz-Perez et al. 2004; Snyder et al. 2015).

Fig. 4.

Daily soil moisture contents (A, B, C, and D) and temperatures (E, F, G, and H), as affected by non-mulching (NM), and polyethylene (PE) and biodegradable F, H, and E films mulched in the onion field in January and April of 2024.

Soil chemical properties

The seasonal soil pH levels did not differ significantly, except for that at 150 DAT, among the treated pepper plots (Fig. 5A). The soil pH ranged from 5.5 to 7.5, with a rapid decline during the period from 60 to 90 DAT (summer season), presumably due to acid deposition stemming from the high amount of precipitation and the leaching of base cations, Ca²⁺ and Mg²⁺ (Yu et al. 2020). The seasonal soil pH remained between 6.5 and 7.0 for all treated onion plots from 60 to 150 DAT but decreased afterwards in the mulching plots (Fig. 5B). Organic decomposition in the mulching plots would release acids and activate nitrification while also releasing protons through plant uptake of cations, causing a decline in the rhizosphere pH (Neina 2019; Al-Busaidi et al. 2022). The seasonal soil EC decreased in both the pepper and onion growing plots owing to nutrient uptake into the roots and nutrient leaching or run off from the fields (Fig. 5C and 5D). The soil EC was significantly higher in the mulching treatment plots than in the NM plots in the pepper field at 0 and 30 DAT, presumably owing to high competition for water and nutrients from weeds and crops in the NM plots (Table 2) (Dıaz-Perez et al. 2004; Kasirajan and Ngouajia 2012; Snyder et al. 2015; Steinmetz et al. 2016; Mansoor et al. 2022). The soil EC increased in the both onion and pepper fields mulched under the F film at 30 DAT, rapidly decreasing thereafter due to its rapid degradation rate and the influence of the water and soil nutrient status (Wang et al. 2014; Sintim et al. 2019; Zhang et al. 2022).

Fig. 5.

Soil pH (A and B) and electrical conductivity (EC; C and D), as affected by non-mulching (NM), and polyethylene (PE) and biodegradable F, H, and E films mulched in the pepper-onion crop-rotation field at different days after transplanting (DAT), where * and ** adjacent to the datum point for each DAT indicate significant differences, as determined by Duncan’s multiple-range test at p < 0.05 and < 0.01, respectively; ns represents not significantly different.

No significant differences were observed in the soil concentrations of OM, NO₃-N, P₂O₅, K₂O, CaO, and MgO among the pepper plots at 135 DAT (Table 1). In the onion field, only the NO₃-N concentration increased for plots mulched with the F film, with decreased P₂O₅ concentrations observed in all BD-film-mulched plots at 217 DAT. This was not consistent with the results of previous studies indicating that BD mulch enhanced the soil OM content and nutrient cycling (Wang et al. 2014; Sintim et al. 2019; Zhang et al. 2022). This occurred because the addition of BD film to the soil stimulates microorganisms and biogeochemical processes with enzyme activities, organic decomposition, and nutrient mineralization, providing nutrient resources for crop uptake but elevating nutrient loss. This would contribute to inconsistent effects on mineral nutrient concentrations in the treatment plots at the end of the growing season (Zhang et al. 2022; Jung et al. 2023; Jin et al. 2024; Kim et al. 2024; Park et al. 2024).

Growth and yield of rotated crop

Stem height increased in peppers grown under PE film mulching at 60 DAT and under F film mulching at 120 DAT (Fig. 6A), with no significant differences observed in the stem diameters during the entire season (Fig. 6C). The number of pepper leaves increased with the BD mulching treatments at 60 and 90 DAT (Fig. 6E), with higher SPAD readings observed at 60 DAT (Fig. 6G). Seasonal leaf SPAD readings gradually decreased from 90 to 150 DAT, in contrast to the increasing trends observed for vegetative growth parameters, with an increased leaf age and reduced total nitrogen (TN) and chlorophyll contents (Costa et al. 2018). No significant differences were observed in the stem height or number of leaves among the onion crops, with the highest values observed for the stem diameter and leaf FW in the E film-mulched onions at 180 DAT (Fig. 6B, 6D, 6F, and 6H). Adverse effects of remaining BD residue on subsequent onion growth were not observed, in agreement with previous results confirming insignificant toxic effects on agronomic crops and the soil environment (Volova et al. 2017; Boots et al. 2019; Zhang et al. 2022; Huang et al. 2023; Park et al. 2024). The stem and leaf growth of onions increased from 0 to 180 DAT and subsequently leveled off with an increase in the bulb size and reduced leaf mass production, similar to outcomes reported in previous studies (Jung et al. 2023; Park et al. 2024).

Fig. 6.

Growth parameters (A-H) affected by non-mulching (NM), and polyethylene (PE) and biodegradable F, H, and E films mulched in the pepper-onion crop-rotation field at different days after transplanting (DAT). Here, * and ** adjacent to the datum point for each DAT indicate significant differences, as determined by Duncan’s multiple-range test at p < 0.05 or 0.01, respectively; ns represents not significantly different.

The fruit length and diameter were not consistently affected by the treatments from 90 to 150 DAT, resulting in no significant differences in the average fruit FW (Fig. 7A, 7C, and 7E). Seasonal bulb size, length, diameter, and average FW values were lower for NM onions at 210 DAT, when rapid bulb enlargement progressed, compared to those of the mulching-treated onions (Fig. 7B, 7D, and 7F). The mulching treatment increased the number of pepper fruits but not the total fruit FW (Table 2). The H-film mulching treatment greatly promoted the number of bulbs, characterized by a very large size, to meet the demands of fresh market consumers (Pelter et al. 2004), resulting in the highest yield of 61.1 ton ha^-1, followed by the E-mulching (59.4 ton), PE-mulching (48.5 ton), F-mulching (43.3 ton), and NM (34.0 ton) treatments. The low bulb production was partially caused by the highly degraded F films mulched on the plots, affecting the low soil available water content in April (Fig. 4B and 4D), which is a critical period with high water and nutrient requirements during bulb development (Fig. 7B, 7D, and 7F) (Pelter et al. 2004; RDA 2021).

Fig. 7.

Fruit growth parameters (A–F), as affected by non-mulching (NM), and polyethylene (PE) and biodegradable F, H, and E films mulched in the pepper-onion crop-rotation field at different days after transplanting (DAT). Here, * and ** adjacent to the datum point for each DAT indicate significant differences, as determined by Duncan’s multiple-range test at p < 0.05 or 0.01, respectively; ns represents not significantly different.

Biodegradation after crop rotation

Images of the biodegradation of microplastics derived from the PE and BD film mulch treatments after the completion of one crop rotation cycle, i.e., after the harvesting of the onions, are shown in Fig. 8. Breakdown of the films did not occur for the PE film at either the surface or at a soil depth of 10 cm whereas all BD films degraded in the topsoil (Fig. 9). Extensive disintegration was observed at a soil depth of 10 cm for all BD films, particularly for the F film, with a low density of 1.73 mg·cm^-2 compared to the H (1.85 mg·cm^-2) and E (2.11 mg·cm^-2) films. The uncertainty regarding the highly degradable F film should be clearly evaluated based on the original resources and chemical structure used for the aforementioned films, as the components (PBAT+PLA) and thickness (0.015 mm) of the F films were similar to those of the H films (Campanale et al. 2024). The weight maintenance of all film materials showed a monthly decrease at both the surface and soil depth of 10 cm from 210 to 270 DAT. Minimal maintenance between 30 and 50% resulted in a BD mulch film outcomes in the following order: E film > H film > F film at a depth of 10 cm at 270 DAT. This indicates that 50–70% of degradation requires approximately 60 days after harvesting and incorporation into the soil, stimulating the activities of soil microorganisms and the enrichment of fungal taxa using the organic C sources supplied from the BD films in the soil (Kasirajan and Ngouajia 2012; Wang et al. 2014; Steinmetz et al. 2016; Bandopadhyay et al. 2018; Mansoor et al. 2022; Wang et al. 2022; Zhang et al. 2022; Jung et al. 2023; Kim et al. 2024).

Fig. 8.

Debris derived from polyethylene (PE) and biodegradable F, H, and E films mulched on both topsoil and soil at a depth of 10 cm in the onion field after the completion of one crop rotation cycle.

Fig. 9.

Weight maintenance of polyethylene (PE) and biodegradable F, H, and E films mulched on topsoil (A) and soil at a depth of 10 cm (B) in the onion field at 210, 240, and 270 days after transplanting (DAT). ** adjacent to the datum point for each DAT indicates significant differences, as determined by Duncan’s multiple-range test at p < 0.01; ns represents not significantly different.

Conclusions

Few studies have examined the effects of BD film mulching on pepper-onion rotation and the microplastics potentially remaining in soil, subsequently affecting the soil environment and crop growth. In this study, the ecophysiological responses of a summer crop, in this case of pepper, and a winter-spring crop, onion in this study, were different even when the same BD film mulching was applied. This was ascribed to the different growth forms, cultivation periods, and weather conditions, which affected the degree of biodegradation and the soil moisture content. The H- and E-film mulches degraded moderately in the rotational fields, particularly in the case of winter onion cultivation, showing mechanical properties and crop productivity comparable to those of conventional PE mulch films cultivated in climactic regions with hot and humid summers and cold and dry winters. Additionally, all BD mulch films remained as solid residue at a rate of less than 50% 60 days after tillage, which would minimize microplastic pollution in the soil and the negative impact on ecosystem functions after one crop rotation cycle. The BD film outcomes confirmed the safe usage of environmentally friendly mulching materials without the need for film removal and with a reduction of approximately 50% of labor work during the harvest period (Lee et al. 2015). However, further studies must be conducted regarding the uncertainty of both the agricultural soil health and agrochemicals for different types of crop rotation affected by the long-term repeated application of mulching with various BD films.