National Organic Standards Board

Crops Subcommittee Material Discussion Document

Biodegradable biobased mulch film

January 7, 2020

I Summary of biodegradable biobased mulch film 

This material has been on the National List of approved synthetic substances since September 30, 2014, 

based upon an October 2012 NOSB recommendation. Historical information on this material is as 

follows:

Reference on the National List: 205.601(b) As herbicides, weed barriers, as applicable (2) Mulches (iii) 

Biodegradable biobased mulch film as defined in §205.2. Must be produced without organisms or 

feedstock derived from excluded methods.

Technical Report: 2012 TR; 2015 Report; NOP Policy Memorandum 15-1; Supplemental Technical 

Evaluation Report 2016

Petition(s): 2012

Past NOSB Actions: 10/2012 NOSB Recommendation; Memo to the NOSB with Report on 

Biodegradable Biobased Mulch Films in Organic Crop Production (Michigan State University, September 

2019) (pdf).

Recent Regulatory Background: Final Rule published 09/30/14 (79 FR 58655); Sunset renewal notice 

published 10/08/2019, 84 FR 53577

I. Background from Subcommittee: Biodegradable biobased mulch films were approved for placement 

on the National List of approved synthetics (Biodegradable Mulch Film Made from Bioplastics) without 

detailing if non-biobased content would be allowed. The vast majority of mulch films in this category 

contain 20% or less of biobased materials, with the remainder consisting of polymers, colorings, and 

other synthetic materials. There are some products that might meet the biobased aspect of this 

material’s definition on 205.2, but are either not biodegradable or are not used widely in production due 

to brittleness or other production issues. 

In January 2015, the National Organic Program issued Policy Memorandum 15-1, to clarify that 

biodegradable biobased mulch film must not contain any non-biobased synthetic polymer feedstocks. 

The NOSB requested a limited scope Technical Review in 2016. The questions asked for this limited 

scope TR from 2016 were as follows:

1. What is the effect on overall soil health, including soil biology, when this material biodegrades?

2. What is the cumulative effect of the continued use of this biodegradable biobased mulch film, 

on soil nutrient balance, soil biological life, and soil tilth, when used in the same area of the field 

for 3-5-10 years?

3. What effect does the breakdown of these polymers have on soil and plant life as well as 

livestock that would graze either crop residues or forages grown the subsequent year after this 

mulch film was used?

4. Are there different cropping systems, climate, soil types or other factors that affect the 

decomposition rate (Examples would be long cold winters, or exceptionally dry conditions, such 

as found in a desert)?

5. Are there metabolites of these mulches that do not fully decompose, and if so, is there an effect 

upon soil health or biological life?

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The TR focused upon biobased biodegradable mulches which contain polymers and the soil and crop 

health effects they may have as they biodegrade. This supplemental TR was inconclusive, since research 

on these materials is currently limited, and the questions above were not answered to the NOSB crop 

subcommittee’s satisfaction. In addition, there are fossil based synthetic fertilizers, used extensively in 

nonorganic agriculture, that break down in the soil and provide nutrients for plants. The reliance on 

natural fertility inputs is one of the areas where organic agriculture is different from nonorganic 

agriculture.

An argument can be made that even though the non-biobased polymers degrading into the soil 

originate from petroleum (a nonrenewable fossil fuel) , the use of this product could be considered 

environmentally friendly since it replaces plastic mulches that are currently removed at the end of the 

harvest season and end up in landfills that do not breakdown for decades if not centuries. The

biodegradable mulches from petroleum-based polymers save labor and time, since the mulch does not 

have to be removed from the field and transported for disposal. 

The NOSB reviewed this material for its five-year sunset renewal in 2017, and decided to relist it as 

written, with the understanding that there were no products on the market that were commercially 

viable made from 100% biobased (no petroleum) materials. The crops subcommittee needed more 

information that addressed our questions above to consider a change to the annotation. If it remained 

on the National List, perhaps manufacturers would be able to develop a product that met that 

requirement of 100% biobased “ingredients”, which was the preferred outcome. 

The National Organic Program reached out to Dr. Ramani Narayan, a researcher with the Department of 

Chemical Engineering and Materials Science at Michigan State University to provide more information 

beyond the Technical Review that had been done in 2016 to the NOSB. The focus of Dr. Narayan’s 

report is the biodegradability of both biobased and petroleum-based mulch films with limited research 

on the effect of these products degrading into the soil over time. Section 2.7 of the report states:

Environmental studies have not shown any adverse impacts associated with the incorporation of 

biodegradable mulch films (BDMs) into the soil to date. More research is needed to monitor any 

potential formation of terrestrial micro and nanoplastics from biodegradable mulch films and 

ensure that there is no residual soil ecotoxicity. There is need for tuning the physicochemical 

properties of the biodegradable mulch films with the needs of specific cropping systems and 

climates. The biodegradable mulch films could provide additional environmental benefits by 

formulating them to deliver macro and micronutrients to the crop as they biodegrade in soil, or 

deliver pesticides directly into the soil. Sintim et al. showed that there was no significant effect 

on soil health over two years of monitoring and that the soil microbial communities did not differ 

much either. They found significant enrichment in bacterial and fungal gene copies under BDM 

treatments over 2 years, but no significant change under PE and no mulch. Another important 

observation was that repeated tillage of BDMs into the soil across 4 years did not impact crop 

yield significantly and had no major effect on crop quality.

While this section points out possible negative issues with some polymers used in the biodegradable 

mulch, the vast majority of the report focused on the positive aspects when the mulch does biodegrade. 

There is discussion that our current regulation protects organic integrity and would not allow the use of 

excluded methods (some of the polymers are extracted from petroleum through the use of bacteria 

created through excluded methods), and does not allow materials to be used that “contribute to 

contamination crops, soil or water.” Organic producers in the European Union are allowed to use this 

petroleum based biodegradable mulch with no requirement on the percentage of bio-based ingredients. 

The EU will be reviewing these mulches in 2024 with possible changes to their annotation. The crops 

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subcommittee has reviewed Dr. Narayan’s report, but feels there are questions that still need to be 

answered, and invite the public to provide their input on these issues.

The NOP has also rescinded policy memorandum 15-1 in October 2019, stating that it was redundant 

with current regulations. The requirement for 100% biobased feedstocks is articulated in the preamble

of the final rule and the status quo remains. Removal of the policy memorandum provides an 

opportunity for the NOSB to revise the current definition (§ 205.2) to reduce the biobased content 

requirement. This discussion document hopes to gain insight from the public and possibly lead to a work 

agenda item for the NOSB to work on this issue.

II Questions:

1. Is the biodegradability of the mulch film the main issue, or should a future annotation 

include other issues?

2. Is there information on the toxicity or effect of all secondary metabolite residues as the 

product breaks down?

3. What is your opinion on mulch films that could be engineered to include macro or micronutrients or pesticides that would then make the mulch film provide more benefits than just 

a mulch?

4. Is the risk/benefit of keeping plastic mulches out of landfills part of the Organic Food 

Production Act criteria the NOSB should consider when reviewing this material?

5. Are there any studies that track the impact on livestock or wildlife (terrestrial, avian and 

aquatic) that might be attracted to consume pieces of the biodegradable plastic before it 

has completely degraded in 2 years or secondary metabolites that remain in the soil and are 

taken up by crops?

6. Should a future annotation try to include consideration that different soils and climates 

might not be able to meet the biodegradability standard set in the annotation, and how 

would certifiers be able to verify the use of the material met the biodegradability standard? 

III Vote in Crops Subcommittee 

Motion to accept the biodegradable biobased mulch film discussion document 

Motion by: Harriet Behar

Seconded by: Asa Bradman

Yes: 6 No: 0 Abstain: 0 Absent: 1 Recuse: 0 

Approved by Jesse Buie, Crops Subcommittee Chair, to transmit to NOSB January 7, 2020

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