Final report for WPDP19-05
Reducing plastic waste in agriculture will increase environmental sustainability, and biodegradable plastic mulch (BDM) can be a sustainable technology as long as BDM provides benefits equal to polyethylene (PE) mulch, reduces labor costs for removal and disposal, completely biodegrades, and causes no harm to soil ecology or the environment. We will develop an in-service training program to disseminate research findings from projects funded by USDA Specialty Crop Research Initiative (SCRI) and Washington State Department of Agriculture (WSDA) at Washington State University for assessment of BDM in annual and perennial vegetable and fruit crop production. Training will include: reading product labels to determine if mulch is biodegradable; impact of BDM on crop production; evaluating BDM weed control during the crop season; costs of BDM; assessing soil for BDM fragments post soil-incorporation; composting BDM; and impact of BDM use on soil health and quality. The training program will include a day-long workshop in year 1, and the development of a web-based training curriculum in year 2. We will disseminate the training through email list serves, Extension in-service training events and professional conferences. The workshop in year 1 will include classroom lectures and discussion combined with hands-on field and laboratory demonstrations of laying BDM as it differs slightly from laying PE mulch, tilling BDM into the soil, and sampling the soil to assess the amount of plastic fragments remaining. All of this information will be video recorded and combined with recordings we gathered during our SCRI and WSDA grant projects. We will catalog all recordings and select and edit for incorporation into the web-based asynchronous curriculum. The curriculum will include PowerPoint presentations, videos and handouts that trainers can use for their own presentations. All training participants will be required to take a pre- and post-training survey to assess knowledge gain and information gaps.
Increase awareness and knowledge of sustainability issues regarding mulch use for crop production, specifically: (1) disposal of PE mulch; (2) BDM ingredients, how they are derived, and how to use this information to assess potential for biodegradation and compostability; (3) impact of using BDMs on annual and perennial vegetable and fruit crops; (4) breakdown of BDMs in soil and compost: and (4) sampling to assess BDMs in soil after till-down.
Year 1 – Develop and deliver a hands-on in-service training program to agricultural professionals for the use and assessment of BDM for annual and perennial vegetable and fruit crop production. This will include a day-long workshop at WSU NWREC in Mount Vernon, where we have tested BDM for the past 4 years in a field experiment. Video record workshop sessions and combine with recordings we gathered during our SCRI and WSDA grant projects. Catalog all recordings and select and edit for incorporation into the web-based curriculum. All training participants will be required to take a pre- and post-training survey to assess knowledge gain, information gaps, and potential changes in practices with producer constituents.
Year 2 – Refine training materials, fill information gaps identified in the hands-on training, and develop the asynchronous curriculum, which will include PowerPoint presentations, videos and handouts that participant-trainers can use for their own presentations. Post the curriculum on-line so it is accessible throughout the western region. Disseminate the training through email list serves, Extension in-service training events and professional conferences throughout the western region. Surveys of participants pre- and post-training will be used to identify any remaining information gaps, and education materials will be developed to fill these gaps. We will include an introduction to the training in our WSU undergraduate and graduate lectures, and we will submit a peer-reviewed article to the Journal of Extension.
- (Educator and Researcher)
- (Educator and Researcher)
The following educational approaches were used in the project:
- Developed training materials including PowerPoint slides, lecture slides for high school, undergraduate and graduate courses, presenter notes, fact sheets, and videos
- Developed website and posted all the educational materials online
- Advertisement of BDM training curriculum
- Conducted professional development workshops
- Farm visit
- Farmers’ field day
Education & Outreach Initiatives
Disseminate BDM knowledge to extension specialists throughout the western region
The following PowerPoint slide sets with accompanying presenter notes on BDM were developed:
- What is BDM?
- Use of PE mulch in strawberry production
- Use of BDM in crop production
- Applying BDM
- Weed control
- Deterioration, degradation, and tilling BDM
- Soil sampling for visible plastic fragments post tillage
- Impact of BDM on soil health and quality
- Economics of BDM use
- Sociological perceptions of BDM
- BDM and fumigation
Five course lectures for high school, undergraduate and graduate courses were developed:
- Brief introduction to BDM
- BDM in agriculture
- BDM for organic production
- BDM overview and weed control
- BDM is effective and affordable
The following fact sheets were developed or updated:
- In-field biodegradation of BDM
- Update on BDMs in organic agriculture
- Glossary of terms associated with BDM for specialty crops
- Soil-fumigation and BDM
- Soil sampling for visible plastic fragments post tillage
- Using mesh bags to assess degradation of BDM
- What is in a BDM?
- Frequently asked questions about BDM
- Mulch use flow chart: Pumpkin
- Mulch use flow chart: Raspberry
- Mulch use flow chart: Strawberry
The following videos were created:
- How to assess mulch deterioration as PSE?
- Soil sampling for visible plastic fragments post tillage
- Using mesh bags to assess degradation of BDM
All these educational materials are posted on our website https://smallfruits.wsu.edu/plastic-mulches/ and can be directly accessed by anyone. We advertised our training curriculum to the agricultural professionals and stakeholders throughout the United States through email listserves.
Students, extension agents and other agricultural professionals have found the website very informative and helpful. Here are a few comments on our curriculum from our colleagues and stakeholders:
- We found your website to be without a doubt the most useful and user-friendly resource in navigating the field of biodegradable mulches! (Undergraduate students working on developing a biodegradable polymer, University of California, Santa Cruz)
- It's really helpful to have all the information about BDMs on one page. It's an impressive wealth of information and once again, WSU sets the bar high! (P. Sarazin, VP R&D and Sustainability at PolyExpert)
- This is extremely useful and helpful for anybody interested in BDM Well done. Thank you and your team for putting this together and making it available for others to use! (Dr. M. Flury, Department of Crop and Soil Sciences, Washington State University)
Provide agricultural professionals the current science-based information on soil-biodegradable plastic mulch and a resource guide for reference information
Professional development trainings were conducted at three different levels (local, regional, and national) to provide agricultural professionals the current science-based information on BDM and a resource guide for reference information. All training participants were encouraged to take a pre- and post-training survey to assess knowledge gain and information gaps.
A local level professional development training was conducted in Watsonville, CA on 4 Feb. 2020. The topics covered in the training are presented in Figure 1. A regional level professional development training was conducted virtually for agriculture professionals in the northeastern United States on 18 Nov. 2020. The topics covered in the training were: 1) introduction to BDM; 2) application and use of BDM; 3) deterioration and degradation of BDM; 4) impact of BDM on soil health and quality; and 5) economics of using BDM. A national level professional development training was conducted virtually for members of the American Society for Horticultural Science (ASHS) on 27 July 2020. The topics covered in the training were: 1) introduction to BDM; 2) application and use of BDM; and 3) deterioration and degradation of BDM.
Local level. There were 28 participants in the workshop among which 21% were representatives from agricultural industries, 29% from organizations, 14% from government agencies, 22% were growers, and 14% were educators. The participants’ overall level of knowledge on BDM increased 41% due to the training program (N = 28, n = 28 where N is the total no. of participants and n is the total no. of respondents) (Fig. 1).
Regional level. There were 58 participants at the training program among which 55% were extension specialists, 20% were teaching or research faculty, 3% were industry representatives, and the rest belonged to the ‘other’ category. After the webinar, 27% of participants responded that they learned a lot from the training session and 41% learned some new information (N = 58, n = 38) (Fig. 2).
National level. There were 30 participants at the training program among which 24% were extension specialists, 38% were teaching or research faculty, 19% were graduate students, and the rest belonged to the ‘other’ category. After the webinar, 48% of participants responded that they learned a lot from the training session and 48% learned some new information (N = 30, n = 21) (Fig. 2).
Figure 1. Participants’ rating (1= low, 5 = high) of their knowledge before and after our professional development workshop in Watsonville, CA on 4 Feb. 2020, and percentage change (N = 28, n = 28).
Change in knowledge on BDM as a result of professional development training:
Figure 2. Grading of knowledge change due to the professional development workshop for extension personnel in the northeastern United States (N = 58, n = 38) (right) and for ASHS members (N = 30, n = 21) (left).
We observed significant changes in awareness and knowledge among Extension and agricultural agency personnel regarding the sustainability issues of using PE mulch and BDM for crop production. Overall, personnel had increased understanding of: (1) impact of BDM on crop yield and quality; (2) petroleum- and biobased feedstocks used to make BDMs, and that the origin of these feedstocks is not a factor determining biodegradability of the BDM; (3) GMOs are commonly used in the fermentation process to produce biobased polymers; (4) naturally occurring soil microorganisms and environmental conditions impact the rate of BDM biodegradation; (5) pathways of BDM biodegradation, from film to fragment to micro-particle to nano-particle to carbon dioxide (CO2), water (H2O) and microbial biomass; (6) how to sample soil to assess the amount of visible mulch (PE or BDM) in the field; (7) how to calculate the on-farm costs associated with BDM use; and (8) how to distinguish a BDM from a non-biodegradable mulch (e.g., oxo- and photodegradable plastic). With this knowledge, participants indicated in the surveys that they were prepared to provide technical assistance to producers. The participants also indicated that they are likely to use the information and resources learned at the workshops.
Gain an understanding of experiences and perceptions of growers using BDM for 1 to 25 years.
A webinar discussing global BDM use was conducted on 1 Mar. 2022 in collaboration with WSU Small Fruit Program, California Marine Sanctuary Foundation, University of California, University of Connecticut, and Cal Poly. A total of 74 participants attended the webinar. Growers from across the United States and Italy who have been using BDM for 1 to 25 years were invited as panelists to share their experience with BDM.
The common reason for switching to BDM as shared by the growers was labor constraint for PE mulch removal at the end of the growing season. The following are key experiences shared by the grower’s panel:
- In the last 20 years, BDM was almost completely gone by spring after tilling it in the previous fall. BDM fragments were quarter the size of initial fragments after tillage.
- BDM degradation is very weather-dependent. BDM biodegrades faster in healthier soil.
- Cost difference per acre between conventional PE mulch and BDM is about $180 and the cost of labor and materials for retrieving plastic fragments is more than $180.
- Fundamental reason for switching to BDM was labor saving. Picking up fragments in wet and cold season during the end of October and November was not favored by employees.
- Use of BDM allows timely planting of cover crops in the fall.
- Customers are happy to see less plastics used on the farm.
Interact with growers in the northeast U.S. who have been using BDM in their commercial production for several years and to gain an understanding of their experiences and perceptions about BDM.
We visited four farms, Cold Spring Brook farm in Berlin, Stone Garden farm in Shelton and Gresczyk farm in Litchfield, Connecticut, and also Confreda farm, the largest farm in Rhode Island. These growers have been using BDM for 4‒5 years and Confreda farm has stopped using PE mulch and today uses BDM on all of their 60 acres. Growers are using the following BDM productes: FilmOrganic, Biogold, Bio360 and Organix. Crops grown with BDM are mainly pepper, tomato, sweet corn, watermelon and squash. Biogold mulch observed in Cold Spring Brook Farm seemed to be photodegradable in consideration of its mechanical strength and cost. White on black and black BDMs were most used on the farms.
Some of the common experiences of growers were:
- Conventional plastic mulch leaves more fragments in the field compared to BDM
- The cost of BDM is expensive in the beginning of the growing season (purchase cost), but cheaper at the end of the season (removal cost)
- Growers can prepare the field for cover crops at the end of the season when the crop is grown with BDM; the mulch is harrowed in after drip tape is removed, which does not require extra field work
- Even with mulch deterioration in the later season, no weed growth occurs
- Some growers shared experience of mulch adhesion with cantaloupes and tomatoes, but this has not affected marketability of crops
- Removal of conventional plastic mulch and picking up fragments at the end of the season is the least liked job of growers
- Weed control and yield is comparable between BDM and conventional plastic mulch
- Growers do not have any concern with BDM fragments after incorporation in the field as they observe that BDM degrades after a year or so
We identified some future opportunities for BDM:
- Develop a fact sheet on how to identify conventional plastic mulch and BDM fragments in the field
- Make videos of growers’ experience with BDM and use them for extension outreach in the western United States
Create awareness of BDM as a new technology, share information and experience among growers.
Following the BDM professional development workshop in Watsonville, CA in Feb. 2020, growers and crop consultants expressed an interest in BDM and curiosity about its performance compared to conventional polyethylene mulch. In CA strawberry production, about 845 lbs of plastic per acre is used each year (drip tape, mulch, fumigation tarp), most of which is landfilled after use. Our team has been collaborating with commercial strawberry growers and research and extension specialists in the Watsonville area of CA, which is a national leader in strawberry production. In June 2020, we hosted a BDM application field day in Watsonville, CA, which was attended by 15 growers and crop consultants. Afterwards, five strawberry growers volunteered to trial 1.1, 1.3, 1.6 and 2.0 mil BDM products on their farms. Mulch application occurred late fall/winter 2020 and strategic interviews and assessments of mulch performance were done with our collaborating extension specialists in CA and co-PI Dr. Lisa DeVetter. Grower response to the BDMs has been very positive and WSU co-hosted a farmers’ field day in Salinas, CA on 17 August 2021 in collaboration with the California Marine Sanctuary Foundation (CMSF), University of California, and Cal Poly. The event included several presentations by faculty and graduate students and covered the topics: 1) Introduction to BDMs and its constituents; 2) Plastics in agricultural soils: distribution and implications; 3) Plastics in soils and its biological consequences; 4) Economics of BDMs; and 5) Measurements for BDM performance. After these presentations, there was a farmer led panel discussion on their experiences with BDMs and tours that showcased the BDM plots. About 40 participants attended the event. Growers reported comparable weed control and fruit yield and quality for BDM and non-degradable plastic mulch (e.g., polyethylene and impermeable films). After 10 months in the field, the BDMs had minimal deterioration. Field trials are expanding in CA as interest builds after these promising first year trial results.
The attendees and growers were impressed with the performance of BDM in comparison to conventional plastic mulch. This led to an increase in the number of growers participating in BDM trials the following years. BDM degradation in the field will further be assessed in this trial.
Educational & Outreach Activities
We developed a BDM training curriculum that includes 11 PowerPoint slide sets with accompanying presenter notes, 11 fact sheets, 3 videos, and 5 lecture slide sets. We posted the training curriculum on our website https://smallfruits.wsu.edu/plastic-mulches/. Students, extension agents, stakeholders and other agricultural professionals have found the website very informative and helpful. Extension and agricultural agency personnel gained awareness and knowledge regarding the sustainability issues of using PE mulch and BDM for crop production. Specifically, personnel had increased understanding of: (1) impact of BDM on crop yield and quality; (2) petroleum- and biobased feedstocks used to make BDMs, and that the origin of these feedstocks is not a factor determining biodegradability of the BDM; (3) GMOs are commonly used in the fermentation process to produce biobased polymers; (4) naturally occurring soil microorganisms and environmental conditions impact the rate of BDM biodegradation; (5) pathways of BDM biodegradation, from film to fragment to micro-particle to nano-particle to carbon dioxide (CO2), water (H2O) and microbial biomass; (6) how to sample soil to assess the amount of visible mulch (PE or BDM) in the field; (7) how to calculate the on-farm costs associated with BDM use; and (8) how to distinguish a BDM from a non-biodegradable mulch (e.g., oxo- and photodegradable plastic). Our project has contributed significantly to filling the knowledge gap regarding BDM. The on-farm demonstration and field day have enabled growers to have first-hand experience with BDM, and awareness about this technology is flourishing among the growers. Consequently, more growers are showing interest to get involved in BDM trials. Our visit to the farms of northeast U.S. has helped us understand the experience and expectations from growers’ perception and identify future opportunities.
- What is in a BDM? (Fact Sheet)
- Glossary of terms associated with soil-biodegradable mulches for specialty crops (Fact Sheet)
- Frequently Asked Questions about Soil-biodegradable mulches (Fact Sheet)
- Soil-Biodegradable Plastic Mulch for Organic Production Systems (Fact Sheet)