Compounds released from unused biodegradable mulch materials after contact with water (2023)

Polymer Degradation and Stability

Volume 178,

August 2020

, 109202

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Biodegradable plastics (BDP) are an alternative to environmental and economical drawbacks of PE agricultural mulches. They are intended to biodegrade into the soil or in compost. BDP materials certified as biodegradable in soil or in compost have passed ecotoxicity biotests after biodegradation, but most BDP ecotoxicity studies do not provide insights on the components these materials may release. The present work aims to characterize the compounds released from BDP to water solutions before biodegradation.

New unused BDP, one paper mulch for agricultural use, a control without any material, and one non-degradable PE mulch, were incubated in a water solution for identification of the released compounds through GC-MS, NMR and UPLC-MS/MS. All BDP released compounds and modified the pH of the solution, with differences depending on the composition of the material. A diversity of compounds used in the formulation of the materials, and their derivatives, were identified in most solutions; mostly, but not exclusively, adipic acid, 1,4-butanediol, lactic acid, glycerol, terephthalic acid, mono and disaccharides, or fatty acids; some were also quantified. Results prove BDP to interact with the environment and to release compounds well before biodegradation may be acknowledged. They are also a step forward towards identifying the links between reported changes in plant development and specific compounds or compound mixtures, and towards a more sustainable and targeted selection and use of BDP for mulching specific plant species in agriculture.


Agricultural biodegradable plastics (BDP) have proven to be a qualified alternative to polyethylene (PE) mulching, technically and agronomically [1]. BDP overcome some undesired environmental and economical drawbacks of PE mulch, such as the need to remove and manage the residue at the end of the crop, and the risk of plastic pieces remaining into the soil or of being delivered to the surrounding environment. Polyethylene accumulation into the soil alters soil biota and decreases soil fertility [2], with an impact on plant development. During the BDP life cycle in the field, the material undergoes an early degradation from laying on. It starts by interacting with weathering agents (UV radiation, rain and irrigation water) before a significant biodegradation begins, then with plants and with the above ground fauna, and finally, after plowing, with soil weathering agents and soil biota. When into the soil, the bio-deterioration, depolymerisation, bio-assimilation and mineralization sequential process follows [3,4]. However, all along this biodegradation pathway, a pool of intermediates and molecules are released.

Available biodegradable plastics for agricultural use are commonly certified as biodegradable in soil or in composting environments [1]. The recent standard EN 17033 [5] considers environmental safety and ecotoxicity requirements. It includes threshold limits for heavy metals and also for potential toxic substances, the later through overcoming biotests in plants, invertebrates and microorganisms. The biotests are focused on identifying the hazards, on the tested organisms, imposed from putative substances released to the environment any time during the biodegradation process, or from degradation products derived thereof. Most ecotoxicity studies [[6], [7], [8]] have been performed, after BDP degradation in soil or in compost, in accordance with the standard and presuming that potential ecotoxic products are released only after this process.

BDP contact with the natural-agricultural environment before being buried into the soil, and abiotic degradation may occur (e.g. hydrolysis) [3]. It is thus likely that products start to be released previously to the onset of in soil biodegradation. Most biodegradable plastics are water insoluble [9]; it has been considered that they are expected not to release compounds and this scenario has previously received little attention. A recent report on the risk of plastic debris in the environment recommends assessing the risk covering all exposure pathways for organisms [10], with water being one of the most essential. Soil and compost are experimental environments entailing recognized associated limitations [11]; the products discharged on them are difficult to be extracted, and the obtained extracts are usually unsuitable for further chemical analysis [12]. Products released from BDP have been scarcely identified in the literature, either from compost [12,13] or from in soil degradation [14]. All three reported cases were performed only after the biodegradable material started biodegradation and only a few specific compounds expected to be released from the materials studied were targeted. Furthermore, the biodegradable materials tested were noticeably different from the ones presently used for agricultural applications.

An invitro plant culture procedure in the laboratory has been proposed as a simple and reliable approach to test ecotoxicity of bioplastic constituents in plants [15]. The system allows identifying effects on plants of compounds released from BDP with several advantages over other procedures. Among others, the test is carried out under strict control of environmental conditions, thus overcoming constrains of using other traditional soil or compost-based biotests. In addition, the test allows to elucidate the presence of putative substances affecting plant development in the testing medium coming from the (bio)degradation of the materials, even though the specific compounds responsible for the reported effects remain unknown and require to be further identified. The test has successfully proven to uncover potential ecotoxic effects of water leachates from unused biodegradable mulch films [16]. The present work aims to characterize chemical compounds released from biodegradable films into water solutions, associated to reported effects of these solutions on plant development.

Section snippets

Reagents and solvents

The aqueous phase for the extraction was MS mineral solution, composed of the macro and micronutrients routinely used for Plant Tissue Culture [17] (Duchefa Biochemie, Amsterdam) (Table1) dissolved in milliQ-quality water (Millipore, Madrid, Spain; conductivity=0.055μScm−1 25°C). The pH of the solution was 4.83 (±0.05) and the conductivity 5.98 (±0.09) mS·cm−1 at 25°C.

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Derivatization was performed with methoxylamine hydrochloride (MEOX, purity 98%, Sigma-Aldrich, Madrid), pyridine (purity

Effects of biodegradable mulches on water solution

The direct contact of the unused biodegradable plastic mulches with the mineral water solution resulted in pH changes and in components of the materials being released to the solution (Table3), as determined after lyophilisation, while conductivity remained basically unaffected. Among biodegradable plastic mulches, the ones richer in carbohydrates (TPS, cereal flour) or PHB released more components, while those with PLA released fewer components. Concurrently, BioFilm® and Mater-Bi® acidified


In this paper compounds from unused biodegradable plastic mulches were released to a water mineral solution closely resembling the soil water mineral composition or transferred from continental water to the sea. Our results demonstrate that, before biodegradation starts, BDP release compounds when in a water environment. Furthermore, these compounds have been qualitatively identified and several of them have been also quantified in the water solution. Concentrations found are low, and far for

CRediT authorship contribution statement

H. Serrano-Ruíz: Investigation, Writing - original draft. J. Eras: Investigation, Writing - original draft. L. Martín-Closas: Investigation, Writing - original draft. A.M. Pelacho: Investigation, Writing - original draft.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.


This work was supported by the University of Lleida grant programme.

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

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      One monomer of PBAT, 1,4-butanediol, was detected upon silylation of the sea water extracts. Similar to our finding, 1,4-butanediol was identified by Serrano-Ruíz et al. (2020) upon silylation among the compounds that migrated into a water mineral phase from bioplastic materials containing PBAT. We cannot argue from the available data whether NIAS were originally present in the material or they have been formed by degradation during the leaching procedure.

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    • A review of biodegradable plastics to biodegradable microplastics: Another ecological threat to soil environments?

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      Citation Excerpt :

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    What is biodegradable mulch made of? ›

    The most common biobased feedstocks used to make biodegradable plastic mulches are starch, polylactic acid (PLA), and polyhydroxyalkanoates (PHA). Paper mulch is completely biobased and made from cellulose (WeedGuardPlus® is an example of a paper mulch).

    What is biodegradable mulching? ›

    Biodegradable mulching film is a suitable alternative to polyethylene plastic film. • Biodegradable film did not affect organic matter and total nitrogen content in soil. • Microbial populations' diversity was associated to the different cover films applied.

    What is the environmental impact of plastic mulch? ›

    Unfortunately, plastic mulch, which can cover between 50 percent and 70 percent of a field, increases surface water runoff from both rainfall and irrigation. That means more of the pesticides applied on plastic-mulched fields makes it into runoff leaving the field.

    Is all mulch biodegradable? ›

    Most mulch materials are biodegradable, such as compost or bark chippings. These are great because they break down naturally and slowly improve your soil whilst adding nutrients.

    What are the benefits of biodegradable mulch? ›

    They help to control weeds and insects, increase soil and air temperature, reduce evaporation, minimize soil erosion, and prevent soil splashing on fruits or vegetables (Figure 1). These benefits translate into reduced pesticide use, early planting in spring, water conservation, and increased crop yield and quality.

    Does mulch release carbon? ›

    Natural mulches are high in carbon, which soil organisms like microbes and fungi need to survive. These organisms feed on the mulch, breaking it down, capturing carbon, and releasing essential nutrients that plants absorb as they grow.

    Does bagged mulch have chemicals? ›

    But cheap bags of mulch, such as those often sold at gas stations, may contain shredded construction debris or other waste with toxic chemicals, metals or lead paint.

    What kind of mulch decomposes? ›

    Organic mulch normally lasts 4-6 years. Though, several factors may cause you to have to replace or replenish mulch every 1-2 years. Organic mulch decomposes over time, so it will need to be replaced eventually.

    How long does biodegradable plastic mulch last? ›

    Biodegradable plastic mulches degraded faster in compost than in soil: degradation, as assessed by surface-area reduction, in compost ranged from 85 to 99% after 18 weeks, and in soil from 61 to 83% in Knoxville and 26 to 63% in Mount Vernon after 36 months.

    Is plastic mulch biodegradable? ›

    Now for the YES! Degradation of plastic by microorganisms, known as biodegradation, is very much a real thing, provided the plastic is made of the polymers that microbes can consume. Soil-biodegradable plastic mulch breaks down into CO2, water, and microbial biomass.

    Is plastic biodegradable how harmful is it to the environment? ›

    Can biodegradable and compostable plastic be bad for the environment? Yes. If these materials are not managed properly once they become waste, then they likely will not break down as intended.

    What are the effects of biodegradable plastics on the environment? ›

    Why is biodegradable plastic bad? Biodegradable plastics are often claimed to be sustainable and better for the planet. These properties are inaccurate and misleading. Not only are biodegradable plastics made from fossil-fuels, they also end up creating microplastics and contaminating other plastics recycling streams.

    Does plastic mulch let water through? ›

    Be aware though, that plants placed in plastic mulch don't get water readily from rainfall or overhead sprinklers so install soaker hoses under the mulch.

    Does unused mulch go bad? ›

    As long as it's dry, a sealed bag can sit indefinitely. Bagged mulch can go sour or moldy in wet areas, or even can attract pests, so proper storage is really all you need for a long-lasting product.

    How long does it take mulch to decompose? ›

    The practical life-time of mulch can be anywhere from 4-7 years. This is how long it takes for a layer of mulch to completely break down, although it depends on a number of different environmental factors (e.g. in direct sunlight, covering very wet ground etc).

    What are 5 disadvantages of mulching? ›

    • Because mulch blocks sunlight, it prevents some seeds from germinating. This is good for keeping weeds away from the beds, but not for your good seeds. ...
    • Slugs, earwigs, cutworms, and other pests love cool, dark, moist places. ...
    • Heavy rains can make the ground soggy for several days.
    Aug 18, 2017

    Does long term use of biodegradable plastic mulch affect soil carbon stock? ›

    Therefore, long-term use of biodegradable plastic mulch could have the potential to increase soil carbon stock, which would benefit soil health.

    What are the disadvantages of organic mulch? ›

    Disadvantages of Organic Mulch

    The main disadvantage is that organic mulch can attract termites and bugs. As a result of its decomposing, you will also need to re-apply every few years.

    What are the benefits of biodegradable materials? ›

    As biodegradable products break down naturally, they eventually decompose and are consumed by soil and other natural components. This natural process means no forced chemical reaction needs to take place to kickstart the process and less pollution will happen as a result.

    What is the green stuff in mulch? ›

    It is called Fuligo septica; or commonly know as Slime Mold or Dog Vomit. While the appearance of this mold may raise a high level of concern the first thing you should know is it is not toxic and will not harm your lawn, garden or plants.

    Does brown mulch have chemicals? ›

    The dyes used in coloring wood mulch are primarily of two types: carbon-based dyes and iron oxide based dyes. Iron oxide, the most commonly used dye, is simply a compound of iron and oxygen. As the compound oxidizes, iron is released to the soil but is not considered to be toxic.

    Is mulch carbon or nitrogen? ›

    You may have guessed by now that mulch contains both carbon and nitrogen (along with small amounts of other essential nutrients).

    Which mulch has least chemicals? ›

    The types of organic mulches that are the least likely to contain any pesticides or herbicides are going to be tree-based: shredded or chipped wood, shredded bark, and pine needles.

    Does mulch have a lot of chemicals? ›

    Unfortunately, some of the recycled waste wood used for making landscape mulch products is contaminated with various chemicals, such as creosote and CCA (chromated copper arsenate). CCA is the chemical that was used in the manufacturing of pressure-treated wood.

    Does mulch give off gases? ›

    The wood mulch undergoes anaerobic fermentation, a process where organisms convert organic matter into compounds such as ethanol and methanol. These volatile compounds accumulate and are released as gases that are toxic to plants.

    What is the best mulch non toxic? ›

    10 Best Organic Mulches for Your Yard
    • Compost.
    • Tree bark.
    • Wood chips.
    • Leaves.
    • Grass clippings.
    • Pine needles.
    • Straw.
    • Aged sawdust.
    Jun 16, 2022

    What is the white stuff under old mulch? ›

    The white stuff is a beneficial fungus that is decaying the organic matter you put into the bed. These fungi, called saprophytic fungi, do not attack plants or cause plant diseases. They feed on dead organic matter, like mulch, compost, soil conditioner, etc.

    What is the problem with mulch? ›

    Mulching Problems

    If not properly selected or used, mulches have disadvantages, such as favoring root diseases and certain weeds and interfering with irrigation. Keep organic mulch and waterproof synthetics 6 inches or more back from trunks to avoid promoting root and crown diseases.

    Does biodegradable plastic degrade in water? ›

    Biodegradable – Biodegradable plastic can be broken down completely into water, carbon dioxide and compost by microorganisms under the right conditions. “Biodegradable” implies that the decomposition happens in weeks to months.

    How long does biodegradable plastic take to decompose in water? ›

    If bioplastics were to end up in the ocean, they would break down into tiny pieces similarly to traditional plastics. According to BBC Science Focus, biodegradable plastics take only three to six months to fully decompose, far quicker than traditional plastic that can take hundreds of years.

    How long does it take for biodegradable products to break down? ›

    Biodegradable plastics take three to six months to decompose fully. That's much quicker than synthetic counterparts that take several hundred years. Exactly how long a biodegradable bag takes to break down depends on various factors, such as temperature and the amount of moisture present.

    Is biodegradable plastic actually plastic? ›

    Biodegradable plastics are still plastics – they are intended for short-lived use and often stay in the environment for a very long time before they actually degrade.

    Is black plastic mulch biodegradable? ›

    It is Certified as Biodegradable and Compostable!! ** NO Residues and toxicities in the ground. Our Bio360 mulch film has been approved by BPI!

    Do biodegradable plastics release toxins? ›

    Highlights. Most bioplastics and plant-based materials contain toxic chemicals. Cellulose and starch-based products induce the strongest in vitro toxicity. Most samples contain >1000 chemical features; the maximum is 20,000 features.

    What is the concern on biodegradable plastic? ›

    It can release harmful substances when breaking down.

    While biodegradable plastic releases fewer harmful chemicals when breaking down, that doesn't mean it's harm-free—certain types of biodegradable plastics can release harmful substances like metals and methane.

    What are the disadvantages of biodegradable plastic? ›

    A downside of biodegradable plastic is that there is a need for costly industrial processors and composters, especially those that require high industrial-scale temperatures to be broken down. Apart from cost, there is a need for the availability of equipment, which may be a problem.

    What are the three harmful effects of biodegradable waste? ›

    Effects of biodegradable substances on environment:
    • Decomposition of biodegradable wastes is accompanied by foul smell which spreads in the environment and affects the people in nearby areas.
    • Heaps of biodegradable wastes act as breeding grounds for houseflies etc, which act as vectors of various diseases.

    What are the effects of biodegradable pollutants? ›

    POLLUTANTS | Effects on Microorganisms

    Biodegradable pollutants will generally increase the net carbon mineralization (respiration) of a soil because of overall increases in microbial activity and microbial cell densities.

    Do biodegradable plastics turn into microplastics? ›

    Under the effects of wave erosion, sunlight, and biodegradation, biodegradable plastic waste will be gradually decomposed into small pieces and left in the ocean to form biodegradable microplastics (BMPs).

    What happens if mulch gets wet? ›

    The mulch can become waterlogged and start to break down, releasing nutrients into the soil that can then be washed away. Additionally, the excess water can lead to mold and mildew growth, both of which can be harmful to your plants.

    What are the disadvantages of plastic mulch? ›

    The Drawbacks of Using Plastic Mulch

    Unlike organic mulch, plastic mulch is not biodegradable. It doesn't break down completely so it ends up in landfills. Plastic products are derived from petroleum-based materials, which are not only costly to produce but also bad for the environment.

    Is it OK to water in mulch? ›

    Watering will lock the mulch in place and help the finer pieces settle to the bottom for maximum weed control. Periodically monitor the soil under the mulch for moisture levels. The soil should feel damp, not soaked. In the summer, if high winds are expected, give your mulch a good soaking to help it stay in place.

    Should you cover unused mulch? ›

    For long-term storage, pour the mulch out onto a tarp and cover it with another tarp to keep it dry. Let some of the edges poke up so air can circulate underneath and keep the mulch dry. Ventilation is important when storing bagged mulch to slow down the decay process and prevent fungal blooms.

    What happens to mulch over the years? ›

    Over time, mulch colors fade due to frequent exposure to sunlight. Regular non-dyed mulch may become a grayish color in one to two months, while dyed brown or black mulches may keep their color for a year or longer. Eventually, all mulches will fade without maintenance.

    Is it OK to store mulch in garage? ›

    Storing Bagged and Bulk Mulch

    Then, simply set the mulch in a dry area for the winter, like a garage or garden shed. To store surplus bulk mulch, place the landscape material on a tarp and cover the pile with a second tarp to keep the supply dry.

    Does mulch break down into compost? ›

    You might wonder if mulch will naturally turn into “compost” if left alone. Given enough time, any natural material will decompose. But most mulching materials take a long time to compost on their own. Wood chippings, bark, and straw are all examples of “brown” (carbon-rich) compost materials.

    Does old mulch turn into soil? ›

    If the old mulch has decomposed appreciably over the course of the winter, work it into the ground as organic matter so that it can serve as a soil amendment, along with the compost.

    Does mulch absorb water? ›

    Mulch acts as a blanket over your soil that cuts down on erosion and protects plant roots from temperature changes. Adding mulch over top of bare soil and around other plants reduces runoff by absorbing water – helping to cut water costs and keep pollutants out of our waterways!

    Is it better to mulch or not mulch? ›

    As you can see, the advantages of mulching far outweigh the disadvantages. Mulch is attractive and benefits the garden by reducing the loss of soil moisture, moderating soil temperatures and inhibiting weed growth. And, if organic mulch is used, it will improve the soil structure and add nutrients as it decomposes.

    What is difference between mulch and compost? ›

    Compost and mulch are terms often used synonymously. However, there is a big difference between the two and are not to be used the same way. Compost is biologically active material that breaks down from organic matter. Mulch, on the other hand, is any material, organic or inorganic, that covers a given soil surface.

    Does biodegradable waste rot? ›

    In composting, the biodegradable wastes are dumped into a big pit and covered for a time period. During this action of microbes, they will decompose and will be used as compost for cultivation purposes.

    What are 3 effects of mulching? ›

    This process has many advantages: mulches are known to buffer soil temperature [2], prevent soil water loss by evaporation [3], inhibit weed germination, and suppress weed growth [4].

    What are the pros and cons of organic mulch? ›

    Organic mulches improve aeration of the soil and guarantee the proper development of the roots because roots can extend deeper into the soil. One of the main disadvantages of organic mulches is that it is expensive to transport because it is bulky. The dried organic mulches are a fire risk.

    What are the effects of biodegradable materials? ›

    Harmful effects of biodegradable waste

    A large amount of microbial flora around the wastes is produced which may increase the risk of communicable diseases in humans, plants, and animals caused by microbes. Bad odor on burning may be produced due to the emission of certain gases.

    Is bioplastic soluble in water? ›

    The bioplastics were also found to be soluble in water and degradable in soil by conducting respective tests, thereby making it environment-friendly. Such bioplastic formulations can be effectively used in packaging applications, due to their advantageous characteristics.

    What are the advantages and disadvantages of biodegradable materials? ›

    Biodegradable plastics don't have a time frame required for certification and are therefore mostly intended to reduce fossil fuel demand. However, these plastics are usually easier to break down and have less chemicals in them. Although, they can certainly possess similar chemicals to plastic such as BPA's.

    What type of mulch does not decompose? ›

    Unlike natural mulches, rubber mulch doesn't decompose, so it's "sustainable." It doesn't add any nasty organic matter to the soil the way bark and pine straw do. Rubber mulch keeps the soil surface cool by trapping all of the sun's heat atop it where your feet are.

    What is the best mulch for decomposition? ›

    Cedar and Cypress bark are good choices. This will decompose more slowly than other options. You'll likely only need to perform minimal maintenance after a couple of years if you're using a good natural mulch.

    What mulch will decompose? ›

    Wood chips, pine bark, leaves, straw, grass clippings – these are all examples of beneficial mulch because they decompose and provide many more benefits to your soil.

    What are the side effects of biodegradable plastic? ›

    List of Disadvantages of Biodegradable Plastics
    • Need for Composters. The flipside of using biodegradable plastics is that there will be a need for industrial composters to turn them into composts and availability of the equipment in some countries can be a problem. ...
    • Engineering Issues. ...
    • Risk of Contamination.

    Does mulch deteriorate? ›

    The practical life of mulch can be between four to seven years. This time is how long it takes for a layer of mulch to break down. When it completely degrades, the mulch will no longer provide ground cover or create heat to protect your plants.

    What is the white powder under old mulch? ›

    The white stuff is a beneficial fungus that is decaying the organic matter you put into the bed. These fungi, called saprophytic fungi, do not attack plants or cause plant diseases. They feed on dead organic matter, like mulch, compost, soil conditioner, etc. They are critical to soil health.

    Does mulch absorb rainwater? ›

    Mulch beds do a much better job of slowing down and absorbing rainwater then lawns. This is because the mulch, as it decays, helps return porosity to our urban soils.

    Should you blend last years mulch into soil? ›

    For an annual bed, remove old mulch before you till the soil and add compost. If you're applying mulch to a perennial bed, you might be tempted to just add a new layer of mulch on top, but this can cause rot, nutrient starvation, and plant death. Remove as much of the old layers as possible before you add more.

    What happens to mulch over time? ›

    Over time, mulch colors fade due to frequent exposure to sunlight. Regular non-dyed mulch may become a grayish color in one to two months, while dyed brown or black mulches may keep their color for a year or longer. Eventually, all mulches will fade without maintenance.

    Is wood mulch biodegradable? ›

    Conventional mulch is also widely used on organic farms although organic farmers and others have questioned its use because it is often non- recyclable, and is generally made from non-biodegradable based materials.

    How do you store unused mulch? ›

    For long-term storage, pour the mulch out onto a tarp and cover it with another tarp to keep it dry. Let some of the edges poke up so air can circulate underneath and keep the mulch dry. Ventilation is important when storing bagged mulch to slow down the decay process and prevent fungal blooms.


    1. Lecture 32 : Biodegradable Plastics
    (IIT Kharagpur July 2018)
    2. Clearflow : No Silt. An Accelerated Sediment Removal Technology
    (Salix - Building with Nature)
    3. Bioplastics & Dissolvable Plastics Video
    (EcoEnclose, LLC)
    4. TPH Risk Evaluation at Petroleum-Contaminated Sites
    (Interstate Technology and Regulatory Council)
    5. how to make leaf compost quickly
    (Home Garden)
    6. Installing Turf Alternatives Workshop 2018
    (ParkTV St. Louis Park)


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