Article

Impacts of biodegradable plastic mulches on soil health

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Abstract

Plastic pollution in agricultural soils, caused by the incomplete removal of polyethylene mulch after usage, is a growing environmental concern. There has therefore been increased interest in biodegradable plastic mulches as alternative to polyethylene mulch; however, little is known about their impact on soil health. We evaluated the effects of four biodegradable plastic mulches on soil health at two sites (Knoxville, TN and Mount Vernon, WA) under pie pumpkin (Cucurbita pepo) production. Cellulosic paper, polyethylene, and no-mulch served as controls. Soil health was first assessed in May 2015, and then every six months until May 2017, by measuring 19 soil properties (physical, chemical, and biological). Soil properties were converted to index scores and aggregated into six soil health indicators and five soil functions. The results showed poor correlations and high spatial variations for most of the soil properties. We performed repeated measure analyses using raw values and change scores to account for the initial variations. The soil properties, soil health indicators, and soil functions were affected more by site and time than by the mulch treatments. Nonetheless, we did observe significant effects of some of the mulch treatments on six soil properties (aggregate stability, infiltration, soil pH, electrical conductivity, nitrate-N, and exchangeable potassium), four soil health indicators (hydraulic, biological, fertility, and salinity & sodicity), and one soil function (nutrient cycling). However, these effects were not consistent among all the biodegradable plastic mulches, across the two sites, and the sampling times. Overall, biodegradable plastic mulches may be a viable alternative to polyethylene. However, evaluation under long-term studies is needed to better establish their effects on soil health.

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... In the case of BDP, while biodegradation processes have been and are the subject of numerous studies in terms of mechanism and kinetics (Chinaglia et al., 2018;Dharmalingam et al., 2015;Hablot et al., 2014;Hayes et al., 2017;Kasirajan and Ngouajio, 2012;Kijchavengkul and Auras, 2008;Singh and Sharma, 2008;Tosin et al., 2019), only a few studies have investigated the effects of these materials on soil functionality, with results that are not always consistent (Bandopadhyay et al., 2018;Li et al., 2014;Qi et al., 2020;Sintim et al., 2019). This is mainly because of the presence of different edaphic factors (i.e. ...
... This is mainly because of the presence of different edaphic factors (i.e. management systems, location, and season), as observed by Sintim et al. (2019). Generally, BDP have been shown to increase microbial biomass, respiration, enzyme activity, and fungal abundance (Li et al., 2014;Muroi et al., 2016); however, Moreno and Moreno (2008) found decreased microbial activity under mulching, and Moore- found minimal effect of BDP on the microbial community. ...
... The lower release of CO 2 from the loamy soil after BDP addition was also evident with the lower doses that caused a reduction in the CO 2 released from soil compared to the control. Therefore, not only the amount of BDP and the related C added to the soil is an important factor in terms of stimuli to SR, but soil characteristics also play an important role in the regulation of this process (Sintim et al., 2019). ...
Article
In agriculture, the use of soil biodegradable mulch films could represent an eco-friendly alternative to conventional plastic films. However, soil biodegradable mulch films incorporated into the soil through tillage, being not only a physical but also a biogeochemical input, is expected to influence the soil quality by affecting its functions. Therefore, the eco-compatibility of these biodegradable plastics needs to be evaluated for their impact on different soil functions. To understand the effect of biodegradable plastics on soil quality (i.e. microbial biomass, nitrogen cycle, and activity of soil enzymes involved in the biochemical processes of carbon and nitrogen), we added increasing quantities of biodegradable plastics in two different soils: a loamy (Cambisol) and sandy (Arenosol) soil. The results highlight that the carbon added through the biodegradable plastics influenced the processes linked to carbon and nitrogen cycles. Significant effects were observed mainly with the highest dose of biodegradable plastics added (1%), resulting in a higher growth of microbial biomass, increased carbon mineralisation, and increased immobilisation of available nitrogen. The results also underline the importance of evaluating the impact of biodegradable plastics in different soils because all the processes considered are also influenced also by soil physicochemical characteristics.
... The long-term use of polyethylene films introduces a significant amount of plastic residues into the soil, seriously damaging agriculture ecosystems (Beriot et al., 2021;Kumar and Sheela, 2020). Biodegradable films, environment-friendly materials, can be directly degraded to CO 2 and H 2 O and retain advantages and overcome shortcomings of plastic films (Filipović et al., 2020;Gu et al. 2017;Sintim et al., 2019). Therefore, it is increasingly common to use biodegradable films to reduce plastic residues in the soil and soil salinization of the root zone while supporting high crop yields (Saglam et al., 2017;Sintim et al., 2021;Yin et al., 2019). ...
... It is thus imperative to evaluate the soil salts distribution in fields drip-irrigated with brackish water under BM and quantify soil salinity variations as a function of the disintegration of the biodegradable film and groundwater table depth. While Sintim et al. (2019) analyzed soil salinity variations under BM, they only focused on seasonal differences before and after the crop growth season. Temporal variations of soil salinity under BM, PM, and NM during different crop growth stages, its spatial variations in a two-dimensional soil profile, and the effects of different degradable rates on soil salinity distributions in the root zone have not yet been studied. ...
... Similar results have been reported in other studies. For example, Sintim et al. (2019) indicated that ECe under BM markedly increased by 0.25 dS m − 1 compared with PM. Zribi et al. (2017) further reported that ECe in the root zone under PM was 42% lower than under NM. ...
Article
Soil salinization caused by shallow, saline groundwater represents a serious threat to field productivity, especially in arid regions with intense soil evaporation. Plastic film mulching (PM) has been increasingly applied to reduce soil evaporation and alleviate soil salinity stress. However, PM introduces into the soil a significant amount of plastic residues. Although biodegradable film mulching (BM) is an ideal alternative to PM due to the degradability of these films, unreasonably high disintegration rates may reduce the benefits of the proposed solution. Understanding the effects of these factors on soil salinity is essential for designing management options for improving water productivity. A two-year cornfield experiment was therefore carried out during 2019–2020 to evaluate differences in soil salt dynamics among treatments with BMs with low, medium, and high disintegration rates (BML, BMM, BMH), one polyethylene film mulching (PM), and no mulching (NM). Additionally, the HYDRUS-2D model was used to evaluate the electrical conductivity of the saturation paste extract (ECe), soil salt fluxes, salt distributions, and salt mass balances in two-dimensional soil profiles under BML, BMM, BMH, PM, and NM. The results showed that calibrated HYDRUS-2D could precisely simulate soil salinity under different mulching treatments. There were large differences between various treatments in the middle and late crop growth stages (Days After Sowing [DAS] 61–140). The highest ECe among different BM treatments occurred in BMH. Additionally, the two-dimensional distribution of soil salinity under BM was affected by irrigation events. The high soil salinity stress area (ECe > 3.80 dS m− 1) occurred one day after irrigation (DAS 108) only under BMH among different BM treatments. Meanwhile, root water uptake (RWU) and crop yield (CY) under BMH were significantly reduced due to excessive accumulation of soil salinity in the root zone under intensive soil evaporation conditions. Compared with BMH and BMM, BML increased CY and the leaching ratio of soil salts from the root zone due to its good performance in water conservation. Thus, BM with a low disintegration rate is more efficient in controlling soil salinization in soils with a shallow groundwater table than BMs with higher disintegration rates due to lower soil evaporation. The findings of this study improve the understanding of the mechanisms of salt dynamics under biodegradable film mulching with different disintegration rates. The study also recommends to the farmers and government a suitable disintegration rate of the biodegradable film that can be adopted to promote field productivity.
... Recently, the rising concerns surrounding plastic pollution have led to a booming market for biodegradable plastic film. Research concerning biodegradable plastic film began in the early 1970s and remains a significant topic of research (Albregts and Howard, 1972; that the so-called biodegradable materials currently available on the market tend to break down into smaller plastic particles rather than completely biodegrade, which leads to the accumulation of bio-microplastic in soils, it is vitally important that more scientific attention be focused on the effects of bio-microplastic accumulation on soil quality (Sintim et al., 2019). ...
... Unfortunately, the plastic mulches are not always removed from the soil after harvest. As a result of machinery tillage and natural degradation, the mulches left on the fields were fragmented into microplastics (MPs, < 5 mm) (Andrady, 2017;Briassoulis, 2004;Palsikowski et al., 2017a;Sintim et al., 2019;Steinmetz et al., 2016). These plastic mulches derived MPs have been identified as one of the main sources of agricultural MPs pollution (Ng et al., 2018;Wierckx et al., 2018). ...
... The increasing concerns surrounding plastic pollution in agriculture have led to the development of biodegradable materials (Bandopadhyay et al., 2018;Sintim et al., 2019). Biodegradable plastic films (BDFs) have been developed as an alternative for conventional low-density polyethylene (LDPE) films. ...
... It has several industries near 18.9000°N 81.3500°E latitude and 81 D-20'37" E longitude. Dantewada city is situated on the riverbank of Dankini and Shankani rivers [4]. As per [4], major of the economy of Dantewada is depends on agro-based industries. ...
... Dantewada city is situated on the riverbank of Dankini and Shankani rivers [4]. As per [4], major of the economy of Dantewada is depends on agro-based industries. Therefore, from this point, it can be understood that the soil quality of the chosen area plays an important role in the growth of agriculture. ...
... . III. Property changing factors of soil (Source:[4]) ...
Article
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The features and properties of the soil can be greatly affected by the influence and activities of the industries and products related to it. This factor may impact on the quality of soil and its level of the fertility. In this context, this research paper has evaluated the chemical and physical characteristics of the soil in the Dantewada region for evaluating and assessing the fertility and chemical ratio status. Ten soil samples have been collected from different industrial location to analysis the physical properties like soil texture, porosity, density and chemical properties like Na, Ca, K, Mg and available micronutrients (Fe, Zn, Cu and Mn). The assessment of the soil quality of the industrial area can help to identify the impact of the industrial wastes on soil and based on those specific measures can be taken. Thus, in the following way this research aims to aid the impact on the soil erosion and pollution to enhancing the crop productivity.
... As the soil nutrient and crop growth conditions are improved, it is more conducive to the nutrient absorption capacity of crops. Sintim et al. (2019) monitored effects of BDMs on nitrate nitrogen, which decreased in two fall seasons, and these differences may be attributed to absorption capacity of different plants. During plant growth, the soil surface was protected by mulch films, which affected nitrate nitrogen loss through leaching or surface runoff [21,22]. ...
... From these soil properties we determined that the BDMs and PEMs might have similar effects on soil environment. When analyzed with raw data of the soil properties, mulch films had significant effects on chemical soil health; in contrast, exchangeable potassium has biologic and fertility effects on the soil health when using change scores [38]. We would use more statistical methods to assess the soil properties to reduce the range of errors in future investigations. ...
... It was shown that the effects of the BDMs did not accumulate over time, but were masked by the effects of time; mulch films and the planting system significantly effect nitrate nitrogen [38], which is probably due to seasonal tillage operations, as tillage resets many soil properties, affecting soil chemistry and fertility [39][40][41], while mulch films may indirectly affect the soil ecosystems through modification of the soil microclimate [10]. Several studies have shown that there were no significant differences in soil microbial community structures covered by BDMs and PEMs [34], in contrast to other studies on BDMs [16,18] and PEMs [42,43], which have observed significant effects. ...
Article
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Plastic film mulching is a common practice to increase vegetable yields. However, the effects of plastic mulch films on different vegetable fields remain largely unknown. In the current study, biodegradable mulch films (BDMs) and polyethylene mulch films (PEMs) were used to explore their effects on three vegetable fields (broccoli, chili pepper and garlic). Compared with bare soil, both BDMs and PEMs could effectively maintain higher exchangeable potassium contents in rhizosphere soil, and significantly increase various soil properties and microbial abundance both in rhizosphere and non-rhizosphere soils. In terms of yields, the treatments of BDMs and PEMs effectively increased broccoli, chili pepper and garlic yields by 17.6–19.0%, 21.3–23.3% and 26.0–29.5%, respectively, when compared with the bare soil. Our initial characterization provided insights into the effects of BMDs and PEMs on soil properties, yields and diversity of rhizosphere and non-rhizosphere microbial communities in three vegetable fields.
... The same experiment revealed that evaporation was higher in soils treated with 2 mm plastics compared to soils treated with 5-and 10-mm plastics and increased with increasing of soil plastics content (Wan et al., 2019). Furthermore, the study conducted by for assessing the impacts of biodegradable plastic mulches on soil health revealed no significant impacts of such mulches on soil properties in short time (Sintim et al., 2019). However, this study and others which worked on biodegradable plastic mulches recommended further surveys and experiments to prove that the same hypothesis can be applied to long term periods (Sintim et al., 2019;. ...
... Furthermore, the study conducted by for assessing the impacts of biodegradable plastic mulches on soil health revealed no significant impacts of such mulches on soil properties in short time (Sintim et al., 2019). However, this study and others which worked on biodegradable plastic mulches recommended further surveys and experiments to prove that the same hypothesis can be applied to long term periods (Sintim et al., 2019;. ...
Article
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Plastics production (i.e 450 million tons per annum globally), use and disposal (i.e 300 million tons per annum globally) are one of the top environmental concerns and global waste management impediments. Nevertheless, nearly 90% of all plastics ever produced to present has never been recycled. Over the past decades, researchers’ voices have repeatedly been raised for acting and saving inland as well as aquatic ecosystems being harmed by the increasing plastic pollution. Microplastics have been reported by several studies to be in tap water, bottled drinks and in fish we eat. Consequently, conventions and agreements have been signed, laws and regulations enforced (banning, increased taxation, etc) in various regions and countries across the globe for lessening plastics harm on the environment. In this struggle, Rwanda looks to be in front line in beating plastic pollution crisis compared to other regional and continental countries; hence resulted in calling its capital Kigali by many, “the Africa’s cleanest city”. This success behind plastics break free could be attributed to Rwanda’s current strong institutional, political will (promotion of plastic recycling and reuse), legal frameworks (e.g non- biodegradable plastic bags ban, outlawing of single-use plastic items, penalties, severe fines, etc) and active citizens (e.g monthly community works also known as umuganda etc) in terms of eliminating plastic pollution, foster socio-economic development and environmental protection. These strategies do not only protect the environment but also save the money that the government would spend in cleaning the cities and facilitate the advertising of the country for its eco-friendliness; resulting in its tourism development. Recently, similar initiatives of reducing or banning plastics have been taken by several governments in African ,, lower-income countries and developed ones from other regions across the globe due to either limited recycling facilities, inadequate plastics trash disposal or as a solution to overcome the increase of plastic pollution which harm humans, farm animals, aquatic lives (fishes, sea turtles, etc), and the environment health. Thus, the present paper reviews the current knowledge of environmental impacts of plastics, approaches adopted for alleviating the harm from plastics in Rwanda and their implementation procedures which gave credits to the country on global environmental protection scene so that lessons from these practices can be implemented by other countries which aim at reducing plastics waste and associated pollution. The current solid waste management (i.e mainly plastics) and challenges are also discussed in order to be addressed by the authority in charge. Data and literature were retrieved from peer-reviewed journal articles, websites, books, reports, dissertations, local and international online newspapers. Despite significant efforts made towards a plastic free country, less has been written on plastic pollution in Rwanda; making it difficult to get reliable data and information for quantifying past impacts of plastic wastes. Furthermore, to the best of our knowledge no scientific research or report has been so far conducted to prove how plastic wastes contributed over the past years to flooding, prevented crops from growing, to what extent plastic litters have restrained rainwater from penetrating various soil types and other forms of plastic pollution in the country. Such studies are paramount for scientifically justify the ban initiatives in the country. This review resulted into encyclopedia that other researchers can build on to better understand environmental impacts of plastics to learn best plastics management practices for a sustainable environment.
... Similarly, Wang et al. (2016a) reported that the higher soil water content and WFPS under PFM can increase soil N 2 O emissions. Therefore, critical evaluations of the impacts of PFM on soil temperature and soil moisture are needed to predict changes in soil N 2 O emissions, which may contribute to the development of sustainable management strategies for N 2 O mitigation (Berger et al., 2013;Sintim et al., 2019). The PFM treatment had higher soil CO 2 emissions than the control treatment ( Fig. 3 and S3) across the two growing seasons, as Zhang et al. (2017) reported. ...
Article
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Greenhouse gas intensity (GHGI), the evaluation of GHG emissions per unit yield rather than per unit land area, has recently received much attention. Plastic film mulching (PFM) is one of the major agricultural practices in semi-arid areas, but few studies have synthetically studied the effects of PFM on GHGI, grain yield, soil characteristics, and their potential relationships at different winter wheat (Triticum aestivum L.) growing stages. Here in the semi-arid Chinese Loess Plateau, we simultaneously investigated two cropping systems from 2018 to 2020: PFM with 100 % cover and no film mulching (control). Averaged across two growing seasons, the PFM treatment significantly increased soil temperature, water-filled pore spaces and soil water storage, while sustaining high aboveground biomass (31.9 %) and grain yield (45.5 %). The PFM treatment significantly increased cumulative N2O emissions by 56.2 %, CO2 emissions by 39.7 %, and CH4 uptake by 151.4 % compared to the control treatment. GHGI are on average 14.2 % lower in the PFM treatment than in the control treatment. Moreover, the PFM treatment significantly improved soil enzyme activities (alkaline phosphatase, catalase, invertase, and urease) and microbial biomass carbon and nitrogen from grain filling to maturity stage. Altogether, the reductions in GHGI suggest that PFM-induced increases in grain yield could outweigh the adverse impacts on GHG emissions, underscoring the potential to apply PFM for sustainable intensification of crop production in semi-arid areas.
... The TN, NH 4 + -N, NO 3 --N, EC decreased with increasing primary microplastic amount in the soil, while TP decreased initially, followed by an increase and then decreased again with increasing primary microplastic amount. Compared with LDPE, the EC, and NO 3 --N of the soil with PBAT added were lower than the blank control, indicating that the addition of PBAT primary microplastics leads to removal of mobile nutrients and salts (Sintim et al., 2019b). The NO 3 --N decreased with increasing PBAT primary microplastic amount in soil. ...
Article
Full-text available
Biodegradable plastics would be gradually degraded by microbes after being used and discarded, forming biodegradable microplastics (BMPs). It is however not clear if it, like conventional microplastics, can affect the original soil ecological balance. In this study, the non-degradable LDPE (low density polyethylene) was used as the reference primary microplastic, and the BMP PBAT (polyadipate/butylene terephthalate) was used as the test object. The effects of the amount of PBAT on soil physical-chemical properties, bacterial community were investigated using high throughput sequencing. The results showed that when the highest amount of PBAT applied was up to 250 times higher than the normal application amount, resulted in a certain dose-effect, and a higher amount of PBAT would reduce the content of NO3⁻-N and TP. The lower amount of PBAT relatively increased the diversity of soil bacterial communities, and the relative abundance of the unique Azotobacter increased with increasing PBAT amount. The abundance of bacterial community in soil with different PBAT amounts was significantly correlated with the soil’s physical-chemical properties. In addition, Mesorhizobium, TM7a and Azotobacter were observed to be highly tolerant bacteria in PBAT containing soil which can be actively explored to study the biodegradation of BMPs PBAT.
... Ecotoxicity assessment of the biodegradable plastic film and its components has attracted much attention, but this research is still in its infancy. The understanding of the effect of biodegradable plastic film on soil environment is mainly based on short-term experiments for several months [37,59]. The long-term impact of the repeated use of biodegradable plastic film on agricultural soil health in the whole crop season and year still needs to be studied. ...
Article
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Biodegradable mulches have become the focus of attention, as pollution caused by leftover plastic mulch material becomes increasingly severe. However, the impact of biodegradable mulches to the soil needs to be further investigated. An experiment was conducted to evaluate the impact of no-mulch, biodegradable film mulch (BM) and polyethylene film mulch (PM) on the soil’s physical, chemical and biological properties after six years (2013–2019) of mulching in garlic growing season in a garlic-maize rotation. Results showed that the soil bulk density of the 10–20 cm soil layer under BM decreased by 12.09–17.17% compared with that under PM. The soil total nitrogen content increased significantly by 14.75–28.37%, and the soil available phosphorus and potassium content increased by 64.20% and 108.82%, respectively. In addition, BM increased the soil’s microbial, soil urease, and soil catalase activities compared with those for PM. To sum up, BM can reduce soil bulk density, and long-term use of BM does not cause a decrease in soil nutrient content and microbial activity. On the contrary, it can improve soil quality. This study helps accumulate data for the environmental safety evaluation of BM and provides theoretical and technical support for the large-scale promotion of biodegradable mulches.
... Within the United States, Bhadha et al. (2018) used CASH with scoring function developed using a CND of means and standard deviations to evaluate flooded rice soils in south Florida. For an evaluation of biodegradable plastic mulch effects on soil health in Washington, Sintim et al. (2019) chose normalized CASH scores to set optimum values because they considered them to be less subjective for indicators such as bulk density and porosity. To evaluate three tillage reduction strategies for market garden systems in Kingston, Rhode Island, Pieper et al. (2015) sent soil samples to Cornell University and then used CASH for evaluation. ...
... Biobased and Biodegradable plastic can be seen as one of the alternatives to accomplish this sustainable growth of the plastic industry and offer a solid alternative to petrochemical plastics in the near future [9] by redirecting part of large volume plastics to other waste management methods and littering single-use plastics that are otherwise difficult to recycle. Simultaneously, contributing to recycling non-renewable materials and environmental protection of biodegradable plastics from renewable resources, biodegradable plastics could serve as a possible solution for overwhelmed landfills [10,11]. Biodegradable plastic may decompose into carbon dioxide (CO 2 ) and water (H 2 O) in 20-45 days if there is enough humidity, oxygen, and an appropriate number of microorganisms, which can be found in natural landfills or manure [12] compared to conventional plastics that their life expectancy is about hundred to thousand years [13,14]. ...
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Plastic usage is increasing the number of pollutants in the environment. Plastic particles and other plastic-based pollutants are found in our environment and food chain, posing a threat to human health. From this perspective, the biodegradable plastics material focuses on creating a more sustainable and greener world with a smaller environmental imprint. This assessment should consider the entire life cycle assessment of the objectives and priorities for producing a wide range of biodegradable plastics. Biodegradable plastics can also have properties similar to traditional plastics while also delivering additional benefits due to their minimised impact on the environment in terms of carbon dioxide, as long as appropriate waste management includes such as composting, are contained. The demand for cost-effective, eco-friendly materials increases to reduce waste management and pollution issues. This study seeks to comprehensively understand biodegradable plastics production and applications research, product prospects, sustainability, sourcing and ecological imprint. Academic and industry interest in biodegradable plastics for sustainability has exploded in recent years. Researchers used the triple bottom line to analyse the sustainability of biodegradable plastics (economic profit, social responsibility, and environmental protection). The research also discusses the variables that influence the adoption of biodegradable plastics and a sustainable framework for improving biodegradable plastics' long-term viability. This study provides a thorough yet simple theoretical design of biodegradable plastics. The research findings and future research endeavours provide a new avenue for further research and contribution to the area.
... Within the United States, Bhadha et al. (2018) used CASH with scoring function developed using a CND of means and standard deviations to evaluate flooded rice soils in south Florida. For an evaluation of biodegradable plastic mulch effects on soil health in Washington, Sintim et al. (2019) chose normalized CASH scores to set optimum values because they considered them to be less subjective for indicators such as bulk density and porosity. To evaluate three tillage reduction strategies for market garden systems in Kingston, Rhode Island, Pieper et al. (2015) sent soil samples to Cornell University and then used CASH for evaluation. ...
Chapter
Soil health assessment tools are needed to quantify effectiveness of various agricultural practices toward meeting sustainable development goals. Although several soil health tools have been developed and tested through global soil management research, ease of use and site-specific accuracy for farmers and agronomists needs to be optimized. This comprehensive review examines the theories, compares approaches, and examines applications of five soil health assessment methods, and then compares their advantages, disadvantages, application limitations, and feasibility before suggesting potential improvements at various scales. The two predominant soil health assessment tools [Soil Management Assessment Framework (SMAF) and Cornell's Comprehensive Assessment of Soil Health (CASH)] were coupled with six classical mathematical models [Principal Component Analysis, Analytic Hierarchy Process, Iterative Algorithm, Entropy weight method, Euclidean distance and Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS)] to create 11 approaches that were compared using field-based soil health indicator measurements. The data were collected from field experiments with cover crops and soil amendments in Mississippi, USA. The Standard Scoring Functions (SSF) associated with the SMAF and the CASH tools were evaluated. Our results, reflecting different data normalization and weighting, created 14 different soil health scores that showed significant differences based on method. Among the three data normalization methods (CASH, SSF, and entropy weighting), soil health scores using SSF were relatively high, while those using entropy weighting were much lower. The latter method, TOPSIS, had the advantage of being able to maximize differences among treatments and thus can help select an optimal management solution. Scores obtained through SSF, SSF + PCA and SSF + AHP had some of the best correlations) with corn (Zea mays L.) and soybean [Glycine max (Merr.) L.] yields, indicating the SSF parameters selected for our study were applicable. CASH provided similar results with a more simplistic approach. Other methods generated soil health scores with poorer fits when compared to the yield data. Overall, we conclude all 11 methods and 14 soil health scores can be useful for soil health evaluation in the study area. The results re-emphasized that soil health assessment is useful for soil researchers, farmers, and any other stakeholder group wanting to determine if specific agricultural practices contribute to sustainable development.
... Biodegradable plastic can be seen as one of the alternatives to accomplish this sustainable growth of the plastic industry and offer a solid alternative to petrochemical plastics in the near future [14]. By redirecting part of large volume plastics to other waste management methods and littering singleuse plastics that are otherwise difficult to recycle and simultaneously contributing to the recycling of non-renewable materials and environmental protection of biodegradable plastics from renewable resources, biodegradable plastics could serve as a possible solution for overwhelmed landfills [15]. With adequate humidity, oxygen, and a suitable quantity of microorganisms, where this condition can be found enough in natural landfills or manure, biodegradable plastic can be decayed into carbon dioxide (CO 2 ) and water (H 2 O) only within 20 to 45 days [16] compared to conventional plastics that their life expectancy is about hundred to thousand years [17,18]. ...
... The contrasting responses of root biomass to PFM with and without N fertilization may be related to soil N status (see above). Soil enzymes are critical indicators for soil health (Sintim et al., 2019). The long-term PFM decreased the activities of all enzymes (except for NAG in the N 135 ) (Fig. 3), suggesting that long-term PFM possibly resulted in declining soil health from a biological standpoint. ...
Article
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Nitrogen (N) fertilization and plastic film mulching (PFM) are two widely applied management practices for crop production. Both of them impact soil organic matter individually, but their interactive effects as well as the underlying mechanisms are unknown. Soils from a 28-year field experiment with maize monoculture under three levels of N fertilization (0, 135, and 270 kg N ha⁻¹ yr⁻¹) and with or without PFM were analyzed for soil organic C (SOC) content, total soil nitrogen (N), root biomass, enzyme activities, and SOC mineralization rates. After 28 years, N fertilization increased root biomass and consequently, SOC by 26% (averaged across the two fertilizer application rates) and total soil N by 25%. These increases, however, were only in soil with PFM, as PFM reduced N loss through leaching, as a result of a diurnal internal water cycle under the mulch. The SOC mineralization was slower with N fertilization, regardless of the PFM treatment. This trend was attributed to the 43% decrease of β-glucosidase activity (C cycle enzyme) and 51% drop of leucine aminopeptidase (N cycle) with N fertilization, as a result of a strong decrease in soil pH. In conclusion, root biomass acting as the main source of soil C, resulted in an increase of soil organic matter after 28 year of N fertilization only with PFM.
... Therefore, the crop yield reduction caused by polyethylene plastic mulch would gradually meet or exceed the yield increase effect brought about by it. The development and utilization of degradable mulch film was the general trend of dealing with "white pollution" (Wang et al., 2004;Liu et al., 2010b;Sintim et al., 2019). ...
Article
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The problem of residual film pollution in farmland caused by polyethylene mulching films is serious. The application effects of different mulching films combined with drip irrigation on maize planting in the Ili area, Xinjiang, China, were explored. In this study, four types of mulching films and non-mulching treatment were used to study the degradation properties of different plastic mulching and their effects on the dynamic changes of soil moisture, heat, and crop yields of maize under drip irrigation. The results showed that after 160 days of mulching film, only small cracks appeared in polyethylene mulching films. The degradation performance of white oxo-biodegradable film treatment was optimal than the black oxo-biodegradable film treatment. The quality loss rate of the two biodegradable films were 52.26 and 48.48%, respectively. Various mulching film treatments could increase soil moisture in the early stage of maize growth. At the 0–60 cm soil layer, the soil moisture under the white oxo-biodegradable mulching film and black oxo-biodegradable mulching film treatments were lower by 2.75 and 2.66% ( p < 0.05) than the white polyethylene mulching film and black polyethylene mulching film treatments. The soil water consumption was highest in the non-mulching treatment, followed by biodegradable film, and the small least value was observed in the polyethylene film treatment. The average soil temperature at depth of 0–15 cm in white polyethylene mulching film, black polyethylene mulching film, white oxo-biodegradable mulching film, and black oxo-biodegradable mulching film treatments were 1.43, 1.16, 0.72 and 0.64°C higher than the non-mulching treatment, respectively. Mulching films treatment played a critical role in increasing production and improving water use efficiency. The black polyethylene mulching film treatment had the highest yield and the best water use efficiency. The black oxo-biodegradable mulching film treatment only reduces the yield by 0.33% compared to the black polyethylene mulching film treatment, and the water use efficiency was only reduced by 0.90% ( p > 0.05). Comprehensive analysis showed that black oxo-biodegradable mulching film could be used as a substitute for polyethylene mulching film and can be applied to the production practice of drip irrigation maize in the Ili area.
... Plastic films are primarily derived from polyethylene, which has an extremely low degradation fraction (Steinmetz et al., 2016;Henry et al., 2019). If the plastic film recovery system is not efficient, mostly a third of plastic film gets accumulated into the soil, adversely affecting agriculture and the environment (Jambeck et al., 2015). ...
Article
The residual film and nitrate nitrogen (NO3-N) leaching are the main sources of non-point pollution in arid fields. To solve the above problems, the DNDC model was first calibrated and validated based on data obtained from plastic film mulching (PM), biodegradable film mulching (BM), and no film mulching (NM) studies performed during 2016 and 2017. The NO3-N content in 0–50 cm soil layer, leaching, uptake, balance and use efficiency (NUE) under PM, BM, and NM with topdressing nitrogen (N) amount of 280 kg ha⁻¹ (PM280, BM280, and NM280) were evaluated using observed and simulated data. Additionally, scenario simulation and prediction tests were carried out using the DNDC model to explore the critical topdressing N amount for BM, PM, and NM. These factors were compared for BM with topdressing N amount of 160 kg ha⁻¹ (BM160) and 220 kg ha⁻¹ (BM220). DNDC model showed remarkably high accuracy in simulating the NO3-N content, leaching, uptake, and yield, with R² and NSE (Nash-Sutcliffe efficiency) of 0.88–0.99 and 0.77–0.99, respectively, during validation studies. During the late growth stage, the corn yield, NO3-N uptake, content, cumulative NO3-N leaching (cum.NL), and NUE for BM280 showed an average decrease of 4%, 1.44%, 8.81%, 0.75%, and 2.04% than PM280, respectively. NO3-N content and cum.NL increased markedly with increasing concentration of topdressing N. NO3-N content and cum.NL was increased by 149.03% and 87.33% for BM280 and 46.71% and 40.7% for BM220, respectively, as compared to BM160. The NUE for BM280 decreased by 30.56% and 18.25% compared to BM160 and BM220, respectively. The scenario simulations showed that 200 kg ha⁻¹ is a critical topdressing N application amount for the arid cornfields, with corn yield of 11,132.1 kg ha⁻¹, cum.NL of 121.33 kg ha⁻¹, and NUE of 42.54%, respectively.
... Biodegradable plastic can be seen as one of the alternatives to accomplish this sustainable growth of the plastic industry and therefore offer a very strong alternative to petrochemical plastics in the near future [13]. By redirecting part of large volume plastics to other waste management methods and littering singleuse plastics that are otherwise difficult to recycle and simultaneously contributing to the recycling of nonrenewable materials and environmental protection of biodegradable plastics from renewable resources, biodegradable plastics could serve as a possible solution for overwhelmed landfills [25]. With adequate humidity, oxygen, and a suitable quantity of microorganisms, where this condition can be found enough in natural landfills or manure, biodegradable plastic can be decayed into carbon dioxide (CO 2 ) and water (H 2 O) only within 20-45 days [26] compared to conventional plastics that their life expectancy is about hundred to thousand years [26]. ...
Article
In line with the recent economic growth, especially in developing countries, human concern for the environment has increased over time. This paradigm shift has influenced many developing countries to pay more attention to the issues related to the use of synthetic plastics. Both industry and consumers are intrigued to discover the: economic characteristics, environmental consequences, and social attitudes to the benefits of biodegradable plastics. Biodegradable plastics are useful in packaging, agriculture, gastronomy, consumer electronics, and the automotive industry. This paper seeks to explain the prospects of biodegradable plastics regarding social, economic, and environmental sustainability and recognizes the latest advances in enzyme-based biodegradation of plastics in order to reduce plastics' negative effects and to make the environment safe. A multi-disciplinary strategy is a unique approach, with studies carried out across the triple bottom line (TBL) approach on three distinct sustainability concepts (economic characteristics, environmental consequences, and social attitudes). These three subjects were carefully chosen for their respective targets. This paper has used ATLAS.ti 9 software tools to thoroughly analyze the literature to save, identify, and assess this study's data. Therefore, the research showed that the environmental component was the most critical factor with the economic second and social third. We review bio-based and biodegradable polymers and highlight the value of biodegradable end-of-life management.
... Polyethylene mulches have been widely used in agriculture for over half a century [44,45]. Most PFs are made of low-density polyethylene that requires at least several hundred years to completely degrade in soil [46,47]. The long-term continuous use of PF results in the deposition of residual PF, and thus irreversible pollution of the soil [45,48,49]. ...
Article
Full-text available
Biodegradable liquid mulch film (LF), which can be degraded naturally without harming the environment, is a new type of covering material that provides an environmentally friendly alternative to plastic mulch film (PF). In this study, the effects of LF and PF (ploughing (CK) used as a control) on the soil and fruit quality of Hutai-8 were evaluated through an experiment, and several soil physicochemical properties and indicators of fruit quality were measured. In-row mulching significantly increased the content of total potassium, available phosphorus, and available potassium in the topsoil (0–20 cm), the ripeness of the grape berries, and the content of phenolics in the skin. The effects were consistent between the two years. The effect of LF was more pronounced in the same year, indicating that LF is an effective alternative to PF. Therefore, LF can be used as an environmentally friendly substitute for PF to improve soil and fruit quality and incorporated into cultivation management plans. Correlation analysis revealed that the content of reducing sugars, flavonoids, total phenols, flavan-3-ols, and anthocyanins, as well as fruit ripeness, increased as the content of total potassium, available phosphorus, and available potassium in the soil increased.
... Based on a limited number of studies, low concentration of PBSA based plastics have no adverse effects on soil microorganisms (bacteria and fungi) and soil ecosystem functions (including nitrification potential and soil esterase activity) [15,40]. These results are consistent with those from studies on other bio-based and biodegradable plastics (e.g., PBS and PBAT), where the incorporation of such plastics into soil is generally not harmful to biological soil health, microbial diversity, and soil ecosystem functions, such as nitrification potential, nutrient cycling, and fertility [41,42]. Nevertheless, a recent study based on high resolution molecular techniques showed that high load of PBSA (6%) caused a significantly decline of archeal, bacterial and fungal richness [21]. ...
Article
Full-text available
Bio-based and biodegradable plastics such as mulching films are widely used in agricultural field sites. However, there are limited studies of their impact on plant development and health even though an important soil-borne plant pathogen F . solani has been reported to associate with various types of bio-based and biodegradable plastics, especially polybutylene succinate-co-adipate (PBSA). To evaluate the influence of PBSA amendment in soils on plant development and health, F. solani and mung bean ( V. radiata ) were used as models in a modified petri-dish test using soil suspensions. Mung bean seeds were incubated in suspensions with two dilutions (high vs. low dilution with low vs. high PBSA amendment) of soils pre-incubated 1 year with PBSA under different treatments (combinations of N fertilizer (ammonium sulfate) and PBSA load) in the modified petri dish test . Plant development and disease incidence were recorded with both microscopic and molecular techniques (specific PCR and Illumina amplicon sequencing). Treatment with PBSA and N fertilizer in non-sterile soil suspensions strongly increased the disease caused by F. solani on V . radiata at both low and high soil dilution. At high soil dilution, the F. solani disease incident was 67.5% while at the low dilution the disease incidence reached 92.5%. In contrast, in treatments PBSA but without N fertilizer, non F. solani disease was observed. Apart from F. solani infection, other soil fungi can also infect the mung bean seedlings, especially at low soil dilution levels. Nevertheless, based on this short-term study, we found no evidence that PBSA alone can significantly increase the overall disease incidence.
... On the contrary, the incorporation of polyethylene plastic mulch into the soil can have a serious negative impact on the environment as a consequence of its poor final disposal [17,53], due mainly to large accumulations of microplastics from the deterioration of the polyethylene [18]. Therefore, recent studies have aimed to increase knowledge of the advantages and disadvantages of different alternatives to polyethylene plastic mulch on different soil parameters [21,23,[54][55][56]. ...
Article
Full-text available
Soil mulching has advantages for horticultural crops, from both agronomic and phytosanitary points of view. The most common material used is polyethylene (PE); however, promising alternatives from the circular economy exist, such as straw (ST) and biodegradable biopolymers (BBs). The effect of the three aforementioned mulches was evaluated and compared to non-mulched soil in a Mediterranean greenhouse for two years of an organic tomato crop. Physical (moisture and temperature) and physicochemical properties of the soil, in addition to crop yield and the effect of the mulches on weed control, were assessed. Additionally, the deterioration of plastic mulches was assessed. The temperature was higher in the mulched soils, but few differences were found between soil and BB at the end of the second cycle. Evaporation was lower in mulched soil, in general, without big differences among the types of mulch. Crop yield did not show differences. At the end of the trials, of the 16 physicochemical variables evaluated, only a slight increase in pH was detected in the ST-mulched plots. BB film degradation reached 5.6% and 6.7% of the total surface at the end of the first and second cycles, respectively. Weeds were equally limited for PE, BB, and ST mulches, but cereal seeds contained within the straw germinated randomly all over the crop cycle. In summary, straw and biodegradable plastic mulches offered the same benefits as conventional PE mulch. Therefore, they can be considered a feasible and more sustainable option, in addition to being consistent with the principles of the bioeconomy.
... There are a lot of studies documenting the presence of microplastics in the soil from different sources (Klamerus et al. 2015;Akram et al. 2018;Raju et al. 2018). However, there is inadequate literature on the effects of soil microplastic contamination on soil health (Sintim et al. 2019;Xu et al. 2020). Thus, it is necessary to critically evaluate the effects of soil microplastic contamination on all soil health parameters. ...
Article
Full-text available
Purpose Soil is a thin coating of matter that covers the earth’s surface, formed through the process of rock weathering. It is a natural filter for impurities in groundwater and is very important to human health. Recently, some studies from around the world have confirmed that the presence of microplastics in soil is increasing. However, most of these studies only examined the impacts of soil microplastic contamination one or two soil health indicators, rather than study all three soil health indicators at once. Methods In this review, we selected papers published internationally in the past decade and examined the trend of the effects of soil microplastic contamination on all three soil health indicators. Results and discussion Soil microplastic contamination resulted in either an increase or decrease in the trend of the effects on physicochemical and biological soil properties. In other cases, microplastic contaminants do not affect soil properties. The alteration of soil health properties by microplastics was associated with a couple of reasons such as microplastic concentrations and types, changes in soil mechanics and microorganisms. Conclusions The current impact and severity of soil microplastic contamination on soil health properties are expected to persist for a long time, especially with increasing global plastic production. Therefore, more research is required to continuously assess the impact of microplastic contamination on other indicators of soil health that has not been studied previously.
... Currently, the most common biodegradable films are additive biodegradable plastic films and fully biodegradable films. The former is produced with conventional plastic materials combined with biodegradable materials or additives such as starch and cellulose (Rosseto et al., 2019), the latter is generally consist of substances that can be completely broken down and metabolized by microorganisms, and its final metabolites are CO 2 and H 2 O without any pollution to the ecological environment (Sintim et al., 2019). These substances briefly include polylactic acid (PLA), polycaprolactone, polybutylene succinate, polybutylene succinate adipate and polybutylene adipate/ terephthalate (PBAT) (Bandopadhyay et al., 2018). ...
Article
Due to increasing concerns regarding plastic pollution throughout the world, biodegradable mulch is considered a promising alternative to polyethylene film and its suitability has been verified in some crops. However, it is unclear whether the long-term continuous use of biodegradable mulch as a substitute for polyethylene film is sustainable in rainfed agricultural areas, and whether its effect is consistent under different climatic conditions. Therefore, we conducted 7-year (2013–2019) and 4-year (2015–2018) field experiments in two regions with different precipitation levels (semiarid and semi-humid regions) on the Loess Plateau in China. We compared the effects of polyethylene film mulching (PM), biodegradable film mulching (BM), and traditional flat planting without film mulching (TF) on the soil temperature, soil moisture, grain yield, crop water productivity (WPc), and economic benefit (EB). The results showed that compared with TF, the grain yields under BM and PM increased by 2.1–93.3% and 7.6–34.6%, respectively, WPc increased by 2.1–93.3% and 7.6–34.6%, and EB increased by –16.6–131.5% and –7.8–27.0%. The differences in these indexes under the two mulching methods mainly occurred in the dry years with less precipitation in the semiarid region, whereas there were no significant differences in the grain yield, WPc, and EB under BM and PM in the semi-humid region. Therefore, the decision regarding whether BM can replace PM to improve maize productivity is significantly affected by the annual precipitation in rainfed areas. Furthermore, the univariate quadratic equation model was used to simulate that BM can obtain a higher crop yield and EB than PM when the precipitation is more than 600 mm and less than 800 mm, so as to achieve a win–win situation with continuous yield and income increases, and environmental friendliness in the Loess Plateau of China. However, the yield increase effect of plastic film mulching is also related to crop types, mulch types and farming practices except for climate. In addition, reducing the production cost will still be important for encouraging farmers to use biodegradable film instead of polyethylene film.
... Although the biodegradable plastic mulches have existed in the market for more than 15 years, studies related to their impact on soil properties (aggregate stability, infiltration, soil pH, electrical conductivity, nitrate-N, exchangeable potassium), soil health indicators (hydraulic, biological, fertility, salinity, and sodicity), and soil functions (nutrient cycling) are limited. A two year evaluation period of soil health under influence of biodegradable plastic agrotextiles (two commercially developed materials made of polyester/starch blends, one commercially developed polyester mulch, complexing film of starch with polyesters, experimental product made of PLA/PHA) revealed that effects of biodegradable plastic mulch on soil health were mostly positive, although these effects were not consistent among the different mulch types, sampling times and site, indicating that additional research should be made [118]. ...
Article
Full-text available
As society becomes more aware of environmental pollution, global warming, and environmental disasters, people are increasingly turning to sustainable materials and products. This includes agrotextiles in a wide range of products, including nonwoven agrotextiles for mulching. This review provides insight into relevant available data and information on the condition, possibilities, and trends of nonwoven mulches from natural fibres, biopolymers, and recycled sources. The basic definitions and differences between biodegradation and composting processes are explained, and the current standards related to biodegradation are presented. In addition, an insight into the biodegradation of various nonwoven mulches and films, including their advantages and disadvantages, is provided, to predict the future directions of nonwoven mulches development.
... Most conventional agricultural plastic mulch is polyethylene (PE), which breaks down into film residuals, gradually resulting in "white pollution" and presenting a thorny issue for farmers who rely on mulched drip irrigation (Sharma and Jain, 2020;Liu et al., 2014). Large amounts of PE film fragments remaining in farmland have worsened soil properties, decreased the crop uptake of water and nutrients (Hu et al., 2019;Gao et al., 2018), and threatened soil and environmental health (Sintim et al., 2019). The accumulation of residual plastic film in the soil has caused various adverse effects on the growth of subsequent crops, such as soil compaction, poor air permeability, decreased fertility level, and aggravated secondary salinization, which will reduce crop yield and quality. ...
Article
Biodegradable films are considered an environmentally-friendly alternative to traditional polyethylene (PE) film mulches, as they effectively reduce film pollution in the farmland when using mulched drip irrigation. However, the effects of different degradable films on soil micro-climate and maize growth have not been examined, especially under different irrigation amounts, which are critical considerations for oasis agriculture in arid areas. Therefore, we conducted a field study in 2019–2020 on maize farmland using two biodegradable films, one with an 80-day induction period (M80) and the other with a 100-day induction period (M100), and compared them with traditional PE film (MPE). Four irrigation amounts (4875, 5250, 5625, and 6000 m³ ha⁻¹) were tested. Our results showed that weight loss rates of M80 and M100 were 7.21 times and 9.63 times higher than that of MPE, and this degradation process was slowed down with increased irrigation amounts. We attribute this mitigation to changes in soil moisture and the physiological characteristics of the crop. Using film of higher resilience together with higher irrigation amount resulted in more active photosynthesis and fluorescence, especially at the later maize growth stage, and improved maize yield compared to the other degradable film. In addition, the reduction in maize yield caused by the use of biodegradable films could be largely compensated for by applying higher irrigation amounts. Our findings recommend using M100 with an irrigation amount of 5625 m³ ha⁻¹ for maintaining maize yields while reducing plastic pollution.
... Similarly, Wang et al. (2016a) reported that the higher soil water content and WFPS under PFM can increase soil N 2 O emissions. Therefore, critical evaluations of the impacts of PFM on soil temperature and soil moisture are needed to predict changes in soil N 2 O emissions, which may contribute to the development of sustainable management strategies for N 2 O mitigation (Berger et al., 2013;Sintim et al., 2019). The PFM treatment had higher soil CO 2 emissions than the control treatment ( Fig. 3 and S3) across the two growing seasons, as Zhang et al. (2017) reported. ...
... Physical abrasion, human farming activities (e.g., harvesting of crops), and other natural forces progressively break down these plastic films into microplastics (MPs, defined as plastics <5 mm in diameter). (Sintim et al., 2019). The widespread use of non-degradable plastic film was reported to be a major source of MPs in agricultural soils (Huang et al., 2020). ...
Article
Microplastics can accumulate in soils and strongly affect the biogeochemical cycle. Biodegradable plastic films show potential as sustainable alternatives that could reduce microplastic soil contamination and accumulation. However, the effects of traditional and biodegradable microplastics on soil organic matter (SOM) stability are not sufficiently understood, particularly under varying temperatures. The objective of this study was to examine the effects of polyethylene (PE) and biodegradable polylactic acid (PLA) microplastics on SOM stability and bacterial community in two contrasting soils (Black soil vs. Loess soil) under varying temperature conditions (15 °C vs. 25 °C). Results showed that microplastics addition significantly enhanced cumulative CO2 emissions and DOC contents, particularly 1 % PLA treatment accelerated CO2 emissions by 19 % – 74 %, DOC content by 3 % – 23 % at 25 °C. A higher temperature sensitivity (Q10) at the PLA treatment indicated that PLA is more susceptible to elevated temperature compared to PE. The presence of both PE and PLA microplastics significantly changed the DOC spectral characteristics, i.e., high temperature increased the value of the specific UV absorbance (SUVA) in soil without microplastics, while decreased it in soil with microplastics. In comparison to soil without microplastics, soil exposed to 1 % microplastics had lower MBC concentrations and greater metabolic quotient. 16S rRNA gene sequencing showed that the presence of PLA microplastic significantly alters soil bacterial community. PE and CK had similar Bray-Curtis distances between two temperatures, while PLA increased the dissimilarity between CK compared to PE. Compared to the two soils, loess soil is more sensitive to microplastics addition. Microplastics have a non-ignorable effect on soil organic matter stability, the interaction between microplastics and soil environment should be considered.
Article
The sole effect of crop straw incorporation or film mulching on soil organic carbon (SOC) content, greenhouse gas (GHG) emission and crop yield is well documented in the literature; however, the combined effects of biodegradable film mulching coupled with straw incorporation on these aspects is not yet studied in detail. We conducted a field experiment expanding over five years to evaluate the influence of different film mulching with straw incorporation treatments: (i) double-ridge furrow sowing with full film mulching plus straw incorporation (DS), (ii) double-ridge furrow sowing with full film mulching (D), (iii) conventional tillage plus straw incorporation (S), and (iv) conventional tillage (CK) on organic carbon contents (SOC), GHG emissions and maize productivity. An average of the results of five years revealed that DS, as compared to CK, increased grain and biological yield by 74.06 % and 29.47 % (P < 0.05), followed by D and S (except for 2017). With every progressing year, DS significantly increased the organic carbon content in the 0–20 cm soil layer with an approximately increase of 17.60 % from 2015 to 2020. A maximum total organic carbon storage of 130.99 Mg C ha⁻¹ in 0–100 cm soil profile was recorded for DS, which was significantly (P < 0.05) higher than other treatments. Conversely, compared with CK, DS increased CO2 and N2O emissions by 34.38 % and 33.95 %, respectively, but significantly reduced the global warming potential (GWP) and greenhouse gas intensity (GHGI) by 41.96 % and 64.91 %, respectively. It is concluded that the use of biodegradable mulch coupled with straw incorporation could be an efficient strategy leading to improved maize yield and organic carbon content, and reduced net global warming potential (NGWP) and GHGI in semi-arid rainfed areas.
Article
In order to improve the shortcomings of paper mulch, such as the low water resistance and weather fastness in practical application, the paper mulch with a superhydrophobic structure was prepared by depositing zinc oxide layer and silicon dioxide layer on the surface of paper mulch by the solution impregnation method, the paper mulch surface treatment method is simple and environmentally friendly. The surface chemical composition and surface morphology of paper mulch before and after UV aging were characterized, respectively. The wetting property, bouncing property, and mechanical stability of paper-based film were studied. The results showed that the static contact angle of the superhydrophobic paper mulch was as high as 161.77°, and the average sliding angle was only 3.5°, which also showed excellent droplet bounce performance and mechanical stability. After UV aging experiment, the static contact angle of super-hydrophobic paper mulch was increased to 163.64°, and the sliding angle was reduced to 2.5°. Its excellent performance could still be maintained, showing excellent UV resistance, which improved the weather fastness and water resistance of paper mulch to a certain extent, and laid a foundation for the next large-scale field test.
Article
The green development of agriculture, the rational use of pesticides, and soil health are closely related. However, our understanding of them is still limited. Pyraclostrobin (PYRA) is one of the most popular strobilurin fungicides due to its broad-spectrum control of fungal diseases. However, PYRA has been shown to have negative effects on bacterial communities and soil enzyme activities under laboratory conditions. The effects of PYRA on soil microbes (mainly bacteria) in actual field environments still need to be addressed. In the present study, after applying PYRA in a wheat/maize rotation field for 2 years, we determined the level of residual PYRA and assessed the soil bacterial community structure, soil enzyme activity, and ammonia-oxidizing functional gene expression. The results show that the DT50 of PYRA in agricultural soil was 2.16–38.93 days. The final residual levels of PYRA in wheat/maize grain were less than 0.01 mg kg⁻¹, which is lower than the maximum residue limit (MRL) recommended (0.2 mg kg⁻¹) by China and the European Union. The culturable fungi and bacteria populations were significantly reduced after applying PYRA. The genera’s abundance (Sphingomonas and Lysobacter) and urease activity associated with phosphorus cycle were inhibited. The amoA genes abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) showed that the N-cycle function of soil microbes was inhibited. Overall, applying PYRA for 2 years did not increase the negative response of soil microbes. However, in some indicators, such as culturable microorganism populations, more significant reductions in populations were observed in the double recommended dose group than in the recommended dose group. The results obtained in this study reflect the response of soil microbes subjected to pyraclostrobin in an actual field and provide new insights into how agricultural development influences soil health.
Article
As an important technology to improve the quality and yield of farmland crops, mulching film has been used in batches of the cultivation of many field crops. However, with people’s attention to environmental problems gradually in recent years, the environmental pollution of traditional plastic mulch makes it unable to be the first choice of field crop cultivation. In response to this problem, the application and research of degradable mulch represented by paper mulch have begun to receive widespread attention. In this paper, combined with the development process of mulch, the current development status of paper mulch in the field was introduced, and the preparation method of paper mulch and the field cultivation effect of paper as mulch in different areas were discussed. The advantages and problems of paper mulch compared with plastic mulch were pointed out according to the corresponding results of literature, and the application of paper mulch in field coverage in the future was prospected.
Article
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.
Article
Although biodegradable plastics are considered an environmentally-friendly alternative to conventional plastics, the effects of biodegradable microplastics (BMPs) on soil faunal communities are poorly understood, especially under field conditions. Here, we investigated the loading impacts of two conventional low-density polyethylene (LDPE) and polypropylene (PP) MPs as well as two biodegradable polylactic acid (PLA) and polybutylene succinate (PBS) MPs at concentrations of 0, 5, 10, and 15 g/m² on soil fauna communities. After 40 d, all MP types did not affect the soil fauna communities. After 130 d, conventional MPs (LDPE-15 and PP-5) significantly increased the abundance of overall soil fauna—attributed mainly to changes in the abundance of Collembola; however, BMPs did not affect the soil fauna communities. Interestingly, MP-induced changes in the abundance and diversity of soil fauna showed a strong tendency to increase over time. Overall, these results indicate that the short-term effects of all MP types on soil faunal communities are inapparent, while soil fauna responses to conventional MPs and BMPs showed slight differences over time. Given these time-dependent soil fauna responses to MPs, we recommend an evaluation of the long-term effects of MPs on soil organisms to gain a comprehensive understanding of their effects on soil ecosystems.
Article
The marvellous and versatile properties of synthetic plastics make them an indispensable part of human lives. But in the recent years, plastic pollution has become the biggest environmental concern for the whole world globally. Environmental distress over plastic pollution associated with a rising debate over fossil fuel dependence and abatement have brought the attention of researchers towards finding a suitable alternative to plastics i.e., bioplastic. Bioplastics are specially designed to have lower carbon footprint, less dependent on natural resources, energy efficiency, environmental safety and sustainability. These are bio-resources based polymers which have the potential of substituting conventional petroleum-based plastics. This review article summarizes need for developing eco-friendly alternative to plastics, bioplastics, importance of bioplastic, advantages of bioplastics over plastics and current trends in production of bioplastics. It also highlights types of bioplastics based on various sources and a variety of bioplastic materials such as starch, cellulose, chitosan, chitin, polyhydroxyalkanoates, polylactic acid, Bio-PE, Bio-PET, Bio-PBS, etc., their synthesis, applications and biodegradability. A comparative analysis of both natural and bio-based polymers in term of their availability, nature, structure, properties such as thermal stability, biodegradability, tensile strength, etc. has also been highlighted.
Article
The perceived variability of plastic soil-biodegradable mulch (BDM) degradation has generated concerns about its functionality and sustainability, especially in climates and regions where biodegradation may be limited. This study evaluated the effects of surface-applied products (compost tea, dairy-based compost, humic and acetic acids) on the surface deterioration and visible degradation of three plastic BDMs (BASF 0.6, Novamont 0.6, and Novamont 0.7) and one cellulose paper mulch (WeedGuard Plus) in a Mediterranean climate. Deterioration was monitored for 10 months, and degradation was evaluated 6- and 12 months following soil incorporation. Deterioration varied between the two years of the study; however, the average deterioration for WeedGuard Plus reached 100%, BASF 0.6 and Novamont 0.6 achieved ≥80%, while Novamont 0.7 reached ≥70%. Application of humic and acetic acids increased BASF 0.6 deterioration, but only humic acid increased Novamont 0.7 deterioration. Scanning electron microscopy of mulch surfaces demonstrated evidence of microbial colonization; however, the surface-applied products did not enhance microbial counts. In-soil degradation of BDMs was inconsistent, but faster degradation occurred overall for starch- and polybutylene adipate-co-terephthalate (PBAT)-based BDMs. Future studies should continue to explore on-farm strategies to enhance in-soil degradation to meet the production system’s goals.
Article
Vegetation restoration on slopes is generally difficult, especially in high altitude areas since the environment has dramatically changing weather conditions that are not suitable for plant growth. In this study, the potential of film mulching for vegetation restoration in such environments and plant growth and nutrients in artificial soil on slopes in high altitude areas were determined. Experiments were carried out in Jiuzhaigou County, Sichuan Province, to determine plant growth and nutrients in artificial soil on slopes under six different coverage rates (40%, 50%, 60%, 70%, 80% and 90%). Results showed that in each observation period, plant height, ground diameter and contents of EN, EP and EK in the soil of the film mulching treatment were significantly higher than those of the control, while the number of plant individuals per unit area was significantly lower than that of the control. When the coverage rate was 90%, plant height, ground diameter, biomass and nutrient contents in the soil were all higher than those under the other five treatments. Overall, our study suggested that applying film mulching technology when performing vegetation restoration on slopes in high altitude areas is promising, since it can promote plant growth and preserve soil fertility.
Article
Drip irrigation technology combined with film mulching has expanded rapidly in arid and semi-arid areas. Without sufficient mulch film recovery, large amounts of plastic film remain in the field, changing the original water infiltration movement, which is not well understood. In this study, structural equation modeling was used to study the impact of residual plastic film (RPF) and emitter flow rate (FR) on the migration time of wetting front (MTWF), soil infiltration aspect ratio (AR) and accumulative infiltration (AI) under different initial moisture content (IMC) and dry bulk density (DBD). The results showed that RPF prevented the downward movement of water, which led to increased MTWF, AI and AR. However, RPF had no direct effect on the AI and infiltration AR, and the effects that it did have on these factors were indirectly influenced by the MTWF. When the RPF content was greater than 480 kg/hm² (with a mulching history of 26 years), the infiltration AR was greater than 1.0. Additionally, there was a parabolic relationship between the emitter FR and the MTWF. When the FR was 0.7 L/h, the MTWF reached its minimum value. Overall, this study explored the process of water movement under drip irrigation infiltration of RPF farmland and provided a theoretical basis for the design of drip irrigation systems for RPF farmland.
Chapter
Biodegradable films and blends are obtained from various macromolecules including proteins, lipids, and polysaccharides, etc. Among these, proteins are highly preferred materials due to their high capacity for forming intermolecular bonds, which are required for film formation and are biodegradable. The protein-based films and blends are produced through either a dry or wet process, which has a significant effect on the properties of the resulting material. Moreover, the dry process is not commonly used to produce biodegradable films and blends, because they lack specified melting points and decompose when heated. The biodegradable blends offer superior properties to the pure polymers due to a synergistic effect between them. This chapter provides an overview of the properties of protein-based biodegradable films and blends made using various techniques. Furthermore, the protein sources and potential applications of protein-based blends and films are also presented.
Article
Biodegradable plastic mulch is potentially a suitable alternative to conventional polyethylene mulch because of the limited disposal options of the latter. However, biodegradable plastic mulch must perform better or comparably to polyethylene mulch to be widely adopted. Gas exchange and soil microclimate are important factors impacted by the use of plastic mulch, which in turn have implications on crop productivity. A controlled-environment study was established in a greenhouse to assess gas exchange and soil microclimate dynamics under biodegradable plastic, polyethylene, and paper mulches with and without planting holes, as well as the impact of the mulches on the growth of sweet corn (Zea mays). A no-mulch condition was included as control. In addition, we monitored CO2 concentrations in the vicinity of planting holes (chimney effect) in a greenhouse and agricultural field conditions under sweet corn production. The plastic mulches (both biodegradable plastic and polyethylene mulches) decreased the soil O2concentration to a minimum of 181–183 mmol mol-1, and when compared to the no-mulch, the plastic mulches reduced water loss within 50 days by 35–68 mm. The paper mulch inhibited light penetration more than did the plastic mulches. There was an increase in the CO2 concentration at 2.5 cm above the planting holes in the plastic mulches compared to that under the no-mulch. However, the differences were not discernible at 15 cm above the ground. Consequently, we did not observe significant impacts on the growth of sweet corn, possibly, because the canopy height of sweet corn was more than 15 cm within a few days after planting. Overall, the plastic mulches did not reduce O2 concentration below 100 mmol mol-1, the minimum level in which plant growth becomes impaired. Also, the often reported improved growth of sweet corn from plastic mulching could be attributable to other factors, such as weed control, reduced water loss, and early season soil warming, rather than elevated CO2 concentrations and fluxes in the vicinity of planting holes. Highlights- Gas exchange and soil microclimate dynamics under biodegradable plastic, polyethylene, and paper mulches were assessed - Elevated CO2 levels were observed near planting holes of plastic mulches (both biodegradable and polyethylene) - The plastic mulches inhibited O2 exchange, but not to a level that could impair plant growth - Polyethylene mulch conserved soil water better than biodegradable plastic and paper mulches - Paper mulch inhibited light penetration better than plastic mulches
Article
Biodegradable mulch film was considered to be a sustainable ecological alternative alleviate of plastic mulch film. Extensive studies related to biodegradable mulch film have been carried out in multiple perspectives. However, there was no systematic synthesis of the studies because of the complex research subjects, diverse research contents, and plentiful research perspectives in this field. In the present study, a bibliometric analysis was applied to analyze the evolution and current status of the research about biodegradable mulch film, so as to reveal research hotspots and predict future trends. The research about biodegradable mulch film had developed from a field concentrated on material development to multi-disciplinary field with three main research knowledge bases: the necessity of degradable mulch film application, mulching on crop production and degradation process of biodegradable mulch film. The study hotspot has shift from development of biodegradable materials to farmland application of the biodegradable mulch film. The ecotoxic of degradation process and degradation products especially for microplastics of biodegradable mulch film on soil environment was getting the attention of scientists. Based on these findings and status quo, three research directions including development of renewable biodegradable materials with higher water resistance performance, farmland suitability evaluation of biodegradable mulch film and safety evaluation of farmland soil with biodegradable film mulching. It is still too early to apply biodegradable mulch film on a large scale because its potential ecotoxicity to soil environments is not identified yet.
Article
Eco-friendly biodegradable PBAT/PLA mulch films are attracting increasing interest in sustainable agricultural production. However, currently, little is known about the service life for the PBAT/PLA mulch films. Herein, PBAT/PLA mulch films are subjected to indoor UV-accelerated degradation (UAD) experiments and field cultivation environment degradation (CED) experiments to systematically investigate the relationship between UAD and CED processes. Results demonstrate that 10 days of indoor UAD treatment corresponds to around 120 days aging under outdoor CED conditions. Using eight PBAT/PLA evaluation indicators (haze, elongation at break, tensile strength, gel content, light transmittance, polydispersity index, Mn, Mw), we established a service life prediction model for PBAT/PLA mulch films based on short-term indoor UAD experiments, which could accurately estimate the long-term service life of the mulch films in the field. In particular, using the haze value, near-perfect correlation (R2 = 0.995 for eq. 1 and R2 = 0.993 for eq. 2) was found between CED days and UAD days. The establishment of these reliable predictive models for the service lifetime of PBAT/PLA mulch films will avoid the undesirable premature breakdown during crop growth, thus fostering end-user confidence in eco-friendly biodegradable mulch films.
Article
Rising concern towards health and environmental menace caused by plastic wastes has fascinated scientists and chemists to find out greener and sustainable alternatives to conventional plastics. The conventional plastics are produced from crude oil and fossil fuels and ever-increasing demand of plastics results in depletion of these natural resources. Moreover, due to non-biodegradable in nature they persist in environment for a long time. A novel, eco-friendly and sustainable substitute to the traditional petro based plastic is biodegradable plastic which can be obtained from renewable and biogenic raw materials such as biomass, starch, wood pulp and vegetable oils. The utilization of renewable sources, their similar applications as conventional plastics, biodegradability, nontoxic properties and high recyclability are the major advantages for the use of biodegradable plastics. They are used for a large variety of applications in various sectors such as, packing, textiles, consumer goods, agriculture and horticulture, automotive and transport, coatings and adhesives, construction, electrical and electronics, medical, food packaging etc. In this mini review various biodegradable plastics, their attainable properties and applications in a wide variety of fields are summarized.
Article
With the rapid increase in the use of plastic films, microplastic (MP) pollution in agricultural soils has become a global environmental problem. Propiconazole is widely used in agriculture and horticulture; however, its role in plastic film degradation remains elusive. Butylene adipate-co-terephthalate (PBAT) and polyethylene (PE) films were used to analyze the effects of propiconazole on plastic film and MP degradation. We identified the surface morphologies of PBAT and PE at different propiconazole concentrations and soil pH values, as well as the adsorption and release characteristics of heavy metals during the degradation process via scanning electron microscopy, Fourier transform infrared spectroscopy and inductively coupled plasma mass spectrometry. Propiconazole accelerated the degradation of MPs, adsorption of heavy metals (Ni and Zn), and release of Sn at low concentrations (≤40 mg/kg); however, these effects were evidently absent at a high concentration (120 mg/kg). Furthermore, MPs were more prone to degradation in acidic or alkaline soils than in neutral soil when they coexisted with propiconazole. Hence, we suggest that PBAT and PE plastic films may not be suitable for application in acidic and alkaline soils with propiconazole, because of shorter rupture time and more heavy metal adsorption. PBAT degraded faster, absorbed and released more heavy metals than PE. Under all tested conditions, the heavy metal contents in MPs gradually approached those in soil, which proves that MPs are carriers of heavy metal pollutants. These results may help in assessing the impact of MPs on soil environments and provide a theoretical basis for the standardized propiconazole and plastic film usage.
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Environmental pollution of microplastics (MPs) is known to be anthropogenically mediated menace to biosphere and becoming a debatable concern globally. Large quantities of plastic fragments are left behind after crop cultivation and like sewage sludge application to soil. The leftover plastic debris, gradually degrade into minute fragments with a diameter of less than 5 mm, known as MPs. MPs are responsible for many changes in the soil physicochemical characteristics, including porosity, enzymatic activities, microbial activities, plant growth, and yield. Because of their ubiquitous nature, high specific surface area and strong hydrophobicity, MPs play an important role in the transportation of toxic chemicals such as plasticisers, polycyclic aromatic hydrocarbons (PAHs), antibiotics, and potentially toxic elements (PTEs). MPs may be transported deep into the soil and can pollute underground water. This review paper investigates the deleterious effects of MPs on the soil environment, enzymatic activities, soil microbes, flora, fauna and crop production, and highlights the general concept of MPs contamination as well as its possible environmental consequences. The review also converses some of the key areas for future research and for key stakeholders concerned with policymaking
Article
The application of biodegradable film mulching (BFM) instead of non-biodegradable film mulching (NBFM) is a promising way to mitigate the negative impacts of residual film in agricultural mulching systems. But the effects of BFM on soil mineral nitrogen (N) are not known. To investigate the effects of BFM on N mineralization, nitrate (NO3⁻) accumulation and leaching, and plant N uptake, we conducted two-year field experiment with five treatments: no-mulching (No-M), white non-biodegradable film mulching (White-NotBioM), black non-biodegradable film mulching (Black-NotBioM), white biodegradable film mulching (White-BioM), and black biodegradable film mulching (Black-BioM). The net N mineralization in NBFM was greater than that in BFM due to the disintegration of biodegradable films in the middle and late stages of maize growth, resulting in a decrease in soil water content under BFM. Higher net N mineralization caused a higher NO3⁻ accumulation in the topsoil (0–20 cm) under NBFM. The NO3⁻ accumulation in the topsoil in Black-NotBioM was 23–88% higher than that in Black-BioM; while in White-NotBioM it was 16–63% higher than that in White-BioM. After two years of cropping, the NO3⁻ accumulation in 100–180 cm (defined as N leaching in deep layers, NLD) in NBFM was 52–63% higher than that in BFM, implying that the higher NO3⁻ accumulation in the topsoil in NBFM caused more N leaching. The yields and plant N uptake were similar between NBFM and BFM, but BFM had higher N harvest index values. Compared with NBFM, BFM showed less NO3⁻ accumulation in the topsoil and less NLD, whereas yield, plant N uptake and net economic benefits were not reduced. Therefore, BFM, especially Black-BioM, could be an alternative to NBFM in maize production on the Loess Plateau. However, the higher N accumulation in root soil layer (0–100 cm) under Black-BioM should be accounted for in N fertilizer management.
Article
Water-saving production technologies are essential for increasing agricultural production under limiting water resources in future periods. Potato, the underground crop needs efficient soil and water management for production sustainability. Field experiments were conducted during the dry season of 2018–19 and 2019–20 to study the effect of rice straw mulch with drip irrigation on soil temperature and moisture content and thereby its effect on the potato yield and water productivity in subtropical India. Potato was grown with two levels of soil management (straw mulch and non-mulch) and four levels of water management, i.e., conventional furrow irrigation and drip irrigation up to full field capacity (100%FC), 90%FC, and 80% FC. The results stated that the straw mulch increased the soil temperature by 0.22–0.90 °C compared to non-mulch plots and the maximum increase was when the air temperature was lowest during the growing period. The straw mulch also increased the soil moisture content (+3.6%) and lowered evapotranspiration (9–14%) compared to the non-mulch. Similar to mulching, the limited drip irrigation (90%FC) increased the soil temperature by ≥ 2 °C as compared to furrow irrigation. The straw mulching effectively increased the tuber yield (+15%) under limited drip irrigation with 90%FC, but not in conventional irrigation. Integration of mulching with limited drip irrigation saved 42–58% irrigation water compared to conventional furrow irrigation without mulch. Straw mulching in drip-irrigated treatments significantly increased the water productivity (30–39%) compared to non-mulch. This study provides a reference point for policymakers that drip irrigation with straw mulch can be a feasible adaptation strategy for increasing potato production in subtropical locations under resource-limited environment.
Article
The application of petroleum‐based plastic worldwide causes the accumulation of plastic waste in landfills, which negatively impacts the environment such as reducing the quality of soil and may cause soil and water pollution. Most of the conventional plastics used have a long lifespan to completely degrade. According to the rapid development of the food industry, plastic packaging plays a key role in food quality and safety, thus making it a major role in controlling the food security system. The alternative use of plastic sources from biopolymers is one of the methods to support environmental sustainability actions. This review provides an overview of studies on principles and challenges of sustainable packaging including different types of biopolymer compounds properties and biodegradability of bioplastics in soil by microorganisms. The biopolymers composition in biodegradable plastic is important in designing better mechanical, physical, and barrier properties during degradation by microorganisms and application in food industries.
Article
Plastic film mulching can help farmers meet food production requirements and even increase output. Although the environmental impact of this mulch has received attention, uncertainty remains about certain soil components and the course of its long-term effects. In particular, it is not clear whether the long-term use of mulching film will affect the electron transfer capacity (ETC) of natural organic matter in the soil. This study evaluated the electron-accepting capacity (EAC) and electron-donating capacity (EDC) of soil humic acid (HA) in different-size aggregates in response to different film mulching years (0–6 years). The EAC of HA in the soil showed a downward trend as mulching years increased, while the EDC fluctuated. EAC decline in microaggregates (MIA) was more significant than that of macroaggregates (MAA). Film mulching changes the physical and chemical properties of soil and the activity of enzymes, changes the chemical structure of HA, and ultimately affects HA electron transfer. In addition, compared with that in MAA, the chemical structure of soil HA in MIA has a stronger correlation with enzyme activity and ETC and thus is more significantly affected by mulching. These results provide an in-depth understanding of the role of HA in soil aggregates of different sizes in processes related to the agricultural soil environment under mulching conditions.
Article
With the increase in plastic pollution of farmland substrate, biodegradable mulch film research has become a hotspot. However, the degradation rate of biodegradable plastic film over the entire crop growth period is still unclear, as well as its impact on crop growth and product quality. Here, several properties of two kinds of composite biodegradable mulch films, PBAT/PLA-[S1] and PBAT/lignin-[S2], are studied with polyethylene-[PE] and uncovered substrate (CK) as controls. We tested the differences in morphological characterization, physical properties, and weight loss rate of the plastic films, as well as the effects of the different plastic films on melon yield and quality, substrate temperature and humidity, physical and chemical properties of the substrate, and substrate fungal species composition. Compared to PE, biodegradable plastic films S1 and S2 increased substrate temperature and the net photosynthetic rate of leaves. The results of substrate 18 s rDNA assay of CK, PE, S1, and S2 after 80 days of treatment and pre-treatment showed that a total of 12 fungal phylum, with 317 fungal genera were found, in which Ascomycota as the main phyla and Penicillium as the main genera. Compared with PE, the S2 treatment significantly increased the single fruit weight, central sugar content and soluble sugar of melon by 225.35 g, 1.26%, and 0.68%, respectively (p < 0.05). When buried for 240 d, the weight loss rate of S2 was significantly increased by 86.08% compared with PE (p < 0.05). From these results, we extrapolated that covering the substrate with the most biodegradable film, PBAT/lignin composite (10 μm), improved the yield and fruit quality of the melon in winter greenhouse production.
Article
Microplastics (MPs), as an emerging pollutant, may cause deleterious changes to the nitrogen cycle in terrestrial ecosystems. However, single impact of MPs and synergistic effects of MPs with hydrochar on ammonia (NH3) volatilization and soil microbiome in paddy fields has been largely unexplored. In this study, Polyethylene (PE), Polyacrylonitrile (PAN) and straw-derived hydrochar (HBC) were selected for observations in an entire rice cycle growth period. Results showed that under the condition of 0.5% (w/w) MPs concentration, presence of MPs alone and co-existence of MPs and HBC (MPs + HBC) unexpectedly mitigated cumulative NH3 volatilization from paddy soil compared with the control with no MPs or HBC addition. MPs + HBC increased NH3 volatilization by 37.8%–46.2% compared with MPs alone, indicating that co-existence of MPs and HBC weaken the mitigation effect of MPs on NH3 volatilization. Additionally, results of nitrogen cycle related microorganisms closely related to NH3 volatilization demonstrated that MPs + HBC altered the bacterial community structure and species diversity. These findings provide an important opportunity to advance our understanding of the impacts of MPs in agricultural environment and soils, and provide a sound theoretical basis for rationalizing the application of HBC in soil with MPs.
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Agricultural plastic mulch films are widely used in specialty crop production systems because of their agronomic benefits. Biodegradable plastic mulches (BDMs) offer an environmentally sustainable alternative to conventional polyethylene (PE) mulch. Unlike PE films, which need to be removed after use, BDMs are tilled into soil where they are expected to biodegrade. However, there remains considerable uncertainty about long-term impacts of BDM incorporation on soil ecosystems. BDMs potentially influence soil microbial communities in two ways: first, as a surface barrier prior to soil incorporation, indirectly affecting soil microclimate and atmosphere (similar to PE films) and second, after soil incorporation, as a direct input of physical fragments, which add carbon, microorganisms, additives, and adherent chemicals. This review summarizes the current literature on impacts of plastic mulches on soil biological and biogeochemical processes, with a special emphasis on BDMs. The combined findings indicated that when used as a surface barrier, plastic mulches altered soil microbial community composition and functioning via microclimate modification, though the nature of these alterations varied between studies. In addition, BDM incorporation into soil can result in enhanced microbial activity and enrichment of fungal taxa. This suggests that despite the fact that total carbon input from BDMs is minuscule, a stimulatory effect on microbial activity may ultimately affect soil organic matter dynamics. To address the current knowledge gaps, long term studies and a better understanding of impacts of BDMs on nutrient biogeochemistry are needed. These are critical to evaluating BDMs as they relate to soil health and agroecosystem sustainability.
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We live in a plastic age (Thompson et al., 2009), with microplastic (typically defined as plastic particles < 5 mm) becoming an increasingly appreciated aspect of environmental pollution. Research has been overwhelmingly focused on aquatic systems, especially the oceans, but there is a current shift to more strongly consider terrestrial ecosystems (Rillig, 2012; Horton et al., 2017). In particular agroecosystems are coming into focus as a major entry point for microplastics in continental systems (Nizzetto et al., 2016b), where contamination might occur via different sources as sludge amendment or plastic mulching (Steinmetz et al., 2016). Given the central role of agroecosystems, including their soil biodiversity (Rillig et al., 2016), in food production, such numbers are potential cause for concern. Field data on measured microplastic presence in agricultural soils are still not widely available, but nevertheless this material is certain to arrive at the soil surface. The fate of material deposited at the soil surface is not clear: particles may be removed by wind or water erosion, becoming airborne, or may be lost by surface runoff (Nizzetto et al., 2016a). Nevertheless, a substantial part of the microplastic (or nanoplastic following further disintegration) is expected to enter the soil. The degree of hazard represented by microplastic to various soil biota is not clear. Direct evidence comes from experimental work on earthworms, on which microbeads had negative effects (Huerta Lwanga et al., 2016; also reviewed in Horton et al., 2017). Data on impacts on other soil biota groups are not available. However, Kiyama et al. (2012) have shown that polystyrene beads can be taken up by the nematode Caenorhabditis elegans; this means the material could also accumulate in the soil food web (Rillig, 2012). Movement into soil is an important aspect of assessing risk: will soil biota be exposed to microplastics? Here, we sketch what is known about movement of such particles in soil, which players and factors could influence this, and we chart avenues for research aimed at the movement and distribution of microplastic in agricultural soils.
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Pollution of residual plastic film in arable lands is a severe problem in China. In this study, the status of residual film and influential factors were investigated using the methods of farm survey in combination with questionnaires and quadrat sampling at a large number of field sites in Xinjiang Uygur Autonomous Region, China. The results showed that the amount of film utilization increased largely and reached to 1.8×10⁵ t in 2013. Similarly, the mulching area also substantially increased in recent decades, and reached to 2.7×10⁵ ha in the same year. According to the current survey, 60.7% of the sites presented a greater mulch residue than the national film residue standard (75 kg ha⁻¹), and the maximum residual amount reached 502.2 kg ha⁻¹ in Turpan, Xinjiang. The film thickness, the mulching time and the crop type all influenced mulch residue. The thickness of the film had significantly negative correlation with the amount of residual film (P<0.05), while the mulching years had significantly positive correlation with it (P<0.05). The total amount of residual film in Xinjiang was 3.43×10⁵ t in 2011, which accounted for 15.3% of the cumulative dosage of mulching. Among all the crops, the cotton fields had the largest residual amount of mulch film (158.4 kg ha⁻¹), and also the largest contribution (2.6×10⁵ tons) to the total amount of residual film in Xinjiang.
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The carbon use efficiency (CUE) of microbial communities partitions the flow of C from primary producers to the atmosphere, decomposer food webs, and soil C stores. CUE, usually defined as the ratio of growth to assimilation, is a critical parameter in ecosystem models, but is seldom measured directly in soils because of the methodological difficulty of measuring in situ rates of microbial growth and respiration. Alternatively, CUE can be estimated indirectly from the elemental stoichiometry of organic matter and microbial biomass, and the ratios of C to nutrient-acquiring ecoenzymatic activities. We used this approach to estimate and compare microbial CUE in >2000 soils from a broad range of ecosystems. Mean CUE based on C:N stoichiometry was 0.269 ± 0.110 (mean ± SD). A parallel calculation based on C:P stoichiometry yielded a mean CUE estimate of 0.252 ± 0.125. The mean values and frequency distributions were similar to those from aquatic ecosystems, also calculated from stoichiometric models, and to those calculated from direct measurements of bacterial and fungal growth and respiration. CUE was directly related to microbial biomass C with a scaling exponent of 0.304 (95% CI 0.237'0.371) and inversely related to microbial biomass P with a scaling exponent of .0.234 (95% CI .0.289 to .0.179). Relative to CUE, biomass specific turnover time increased with a scaling exponent of 0.509 (95% CI 0.467'0.551). CUE increased weakly with mean annual temperature. CUE declined with increasing soil pH reaching a minimum at pH 7.0, then increased again as soil pH approached 9.0, a pattern consistent with pH trends in the ratio of fungal : bacteria abundance and growth. Structural equation models that related geographic variables to CUE component variables showed the strongest connections for paths linking latitude and pH to β-glucosidase activity and soil C:N:P ratios. The integration of stoichiometric and metabolic models provides a quantitative description of the functional organization of soil microbial communities that can improve the representation of CUE in microbial process and ecosystem simulation models.
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This edition updates a narrative that has been at the forefront of soil science for more than a century. The first edition, published in 1909, was largely a guide to good soil management for farmers in the glaciated regions of New York State in the northeastern U.S. Since then, it has evolved to provide a globally relevant framework for an integrated understanding of the diversity of soils, the soil system and its role in the ecology of planet Earth. The 15th edition is the first to feature full-color illustrations and photographs throughout. These new and refined full color figures and illustrations help make the study of soils more efficient, engaging, and intellectually satisfying. Every chapter has been thoroughly updated with the latest advances, concepts, and applications. Hundreds of new key references have been added. The 15th edition, like preceding editions, has greatly benefited from innumerable suggestions, ideas, and corrections contributed by soil scientists, instructors, and students from around the world. Dr. Nyle Brady, although long in retirement and recently deceased, remains as co-author in recognition of the fact that his vision, wisdom and inspiration continue to permeate the entire book. This edition,1082 pages in length, includes in-depth discussions on such topics of cutting edge soil science as the pedosphere concept, new insights into humus and soil carbon accumulation, subaqueous soils, soil effects on human health, principles and practice of organic farming, urban and human engineered soils, cycling and plant use of silicon, inner- and outer-sphere complexes, radioactive soil contamination, new understandings of the nitrogen cycle, cation saturation and ratios, acid sulfate soils, water-saving irrigation techniques, hydraulic redistribution, cover crop effects on soil health, soil food-web ecology, disease suppressive soils, soil microbial genomics, indicators of soil quality, soil ecosystem services, biochar, soil interactions with global climate change, digital soil maps, and many others. In response to their popularity in recent editions, I have also added many new boxes that present either fascinating examples and applications or technical details and calculations. These boxes both highlight material of special interest and allow the logical thread of the regular text to flow smoothly without digression or interruption. For students: This book provides both an exciting, accessible introduction to the world of soils as well as a reliable, comprehensive reference that you will want to keep for your professional bookshelf. What you learn from its pages will be of enormous practical value in equipping you to meet the many natural-resource challenges of the 21st century. The book demonstrates how the soil system provides many opportunities to see practical applications for principles from such sciences as biology, chemistry, physics, and geology. Throughout, the text highlights the countless interactions between soils and other components of forest, range, agricultural, wetland, and constructed ecosystems. As the global economy expands exponentially societies face new challenges with managing their natural resources. Soil as a fundamental natural resource is critical to sustained economic growth and the prosperity of people in all parts of the world. To achieve balanced growth with a sustainable economy while improving environmental quality, it will be necessary to have a deep understanding of soils, including their properties, functions, ecological roles and management. I have tried to write this textbook in a way designed to engage inquisitive minds and challenge them to understand soils and actively do their part as environmental and agricultural scientists, in the interest of ensuring a prosperous and healthy future for humanity on planet Earth. It is my sincere hope that this book, previous editions of which have served so many generations of soil students and scientists, will continue to help future generations of soil scientists to benefit from a global ecological view of soils.
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The spatial heterogeneity of soil and weed populations poses a challenge to researchers. Unlike aboveground variability, below-ground variability is more difficult to discern without a strategic soil sampling pattern. While blocking is commonly used to control environmental variation, this strategy is rarely informed by data about current soil conditions. Fifty georeferenced sites were located in a 0.65 ha area prior to establishing a long-term field experiment. Soil organic matter (OM) and weed seed bank populations were analyzed at each site and the spatial structure was modeled with semivariograms and interpolated with kriging to map the surface. These maps were used to formulate three strategic blocking patterns and the efficiency of each pattern was compared to a completely randomized design and a west to east model not informed by soil variability. Compared to OM, weeds were more variable across the landscape and had a shorter range of autocorrelation, and models to increase blocking efficiency resulted in less increase in power. Weeds and OM were not correlated, so no model examined improved power equally for both parameters. Compared to the west to east blocking pattern, the final blocking pattern chosen resulted in a 7-fold increase in power for OM and a 36% increase in power for weeds.
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There is an urgent need to match food production with increasing world population through identification of sustainable land management strategies. However, the struggle to achieve food security should be carried out keeping in mind the soil where the crops are grown and the environment in which the living things survive. Conservation agriculture (CA), practising agriculture in such a way so as to cause minimum damage to the environment, is being advocated at a large scale world-wide. Conservation tillage, the most important aspect of CA, is thought to take care of the soil health, plant growth and the environment. This paper aims to review the work done on conservation tillage in different agro-ecological regions so as to understand its impact from the perspectives of the soil, the crop and the environment. Research reports have identified several benefits of conservation tillage over conventional tillage (CT) with respect to soil physical, chemical and biological properties as well as crop yields. Not less than 25% of the greenhouse gas effluxes to the atmosphere are attributed to agriculture. Processes of climate change mitigation and adaptation found zero tillage (ZT) to be the most environmental friendly among different tillage techniques. Therefore, conservation tillage involving ZT and minimum tillage which has potential to break the surface compact zone in soil with reduced soil disturbance offers to lead to a better soil environment and crop yield with minimal impact on the environment.
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Recent increases in corn (Zea mays L.) production in the U.S. Corn Belt have necessitated the conversion of rotations to continuous corn, and an increase in the frequency of tillage. The objective of this study was to assess the effect of rotation and tillage on soil physical and chemical properties in soils typical of Illinois. Sequences of continuous corn (CCC), 2-yr corn–soybean [Glycine max (L.) Merr.] (CS) rotation, 3-yr corn–soybean–wheat (Triticum aestivum L.) (CSW) rotation, and continuous soybean (SSS) were split into conventional tillage (CT) and no-till (NT) subplots at two Illinois sites. After 15 yr, bulk density (BD) under NT was 2.4% greater than under CT. Water aggregate stability (WAS) was 0.84 kg kg –1 under NT compared to 0.81 kg kg –1 under CT. Similarly, soil organic carbon (SOC) and total nitrogen (TN) were greater under NT than under CT with SOC values for 0 to 60 cm of 96.0 and 91.0 Mg ha –1 and TN values of 8.87 and 8.40 Mg ha –1 for NT and CT, respectively. Rotations affected WAS, TN, and K levels with WAS being greatest for the CSW rotation at 0.87 kg kg –1 , decreasing with more soybean years (CS, 0.82 kg kg –1 and SSS, 0.79 kg kg –1). A similar pattern was detected for TN and exchangeable K. Results indicated that while the use of NT improved soil quality, long-term implementation of continuous corn had similar soil quality parameters to those found under a corn–soybean rotation.
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This study was conducted to know cropping cycles required to improve OM status in soil and to investigate the effects of medium-term tillage practices on soil properties and crop yields in Grey Terrace soil of Bangladesh under wheat-mungbean-T. aman cropping system. Four different tillage practices, namely, zero tillage (ZT), minimum tillage (MT), conventional tillage (CT), and deep tillage (DT), were studied in a randomized complete block (RCB) design with four replications. Tillage practices showed positive effects on soil properties and crop yields. After four cropping cycles, the highest OM accumulation, the maximum root mass density (0–15 cm soil depth), and the improved physical and chemical properties were recorded in the conservational tillage practices. Bulk and particle densities were decreased due to tillage practices, having the highest reduction of these properties and the highest increase of porosity and field capacity in zero tillage. The highest total N, P, K, and S in their available forms were recorded in zero tillage. All tillage practices showed similar yield after four years of cropping cycles. Therefore, we conclude that zero tillage with 20% residue retention was found to be suitable for soil health and achieving optimum yield under the cropping system in Grey Terrace soil (Aeric Albaquept).
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For widespread adoption of biodegradable plastics as agricultural mulches, dependable biodegradation across contrasting conditions is necessary. The in situ degradation of four potentially biodegradable mulches (two commercially available starch-based films, one commercially available cellulose paper mulch, and one experimental spunbond polylactic acid mulch) were evaluated by measuring percent area remaining (PMAR) after burial for 6, 12, 18 and 24 months in high tunnel and open field tomato production systems at three geographically distinct U. S. locations (Knoxville, TN; Lubbock, TX; Mount Vernon, WA). The PMAR of the mulches did not differ between high tunnel and open field systems at any location, and PMAR of cellulose mulch was 0% within 12 months but >90% for experimental spunbond at 24 months. The PMAR of the two starch-based products did vary by location, and was lowest at Lubbock (˜2%) compared to Knoxville (49%) or Mount Vernon (89%). Relative to the other two locations, Lubbock had the greatest soil diurnal temperature range, maximum daily soil temperature, an alkaline soil pH and a microbial community structure characterized by a relatively high abundance of fungi. Mulch type and geographic location exerted a greater influence on PMAR than did production system, and abiotic and biotic variables influenced degradation.
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Chapter
This chapter describes the state of the art of the agronomic effects of degradable bioplastics used as agricultural films. Current use of bioplastics and certified commercial biodegradable materials, both as granulates and as final products, are introduced. Following, agronomic effects on crops are reported and compared to the routinely used oil-based nondegradable plastics, basically the polyethylene films. Biodegradable films for agriculture were initially developed mostly for mulching application, which still remains the most significant one. Since last reviews published in 2011, new progress and perspectives have mainly arisen regarding the agronomic effects of biodegradable mulching on vegetable crops, not only as films but also as nonwoven biobased mulches. The film mechanical laying and the effects on yield, earliness, product quality, weed control efficacy, microclimatic improvement and film soil coverage and degradation are presented in detail for tomato crops and for other crops where mulching is a common technique (pepper, melon and other cucurbits, strawberry, lettuce,…). Some information is provided for crops not so frequently mulched (broccoli, sweet potato, sweet corn). New findings published on the use of biodegradable films for solarisation are also reviewed, while no significant progress on the use of films for low tunnel covers has been made. Recent proposals for vineyards and future potential application of bioplastics for orchard crops are also addressed. Finally, pros and cons for the adoption of biodegradable films for cultivating crops are discussed.