Progress 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 and presenter notes
- Created lecture slides for high school, undergraduate and graduate courses
- Created fact sheets
- Posted the new educational materials online
- Advertisement of BDM training curriculum
- Farm visit
- Farmers’ field day
Education & Outreach Initiatives
Disseminate BDM knowledge to a large number of people
We developed a new PowerPoint slide set on ‘BDM and fumigation’ and 2 lecture slide sets on ‘BDM for organic production’ and ‘BDM is effective and affordable’ along with presenter notes. We developed fact sheets entitled ‘Mulch use flow chart’ for pumpkin, raspberry and strawberry, ‘Soil fumigation and BDM’, ‘What is in a BDM?’, and updated the fact sheets ‘Glossary of terms associated with BDM for specialty crops’ and ‘Soil-biodegradable plastic mulch for organic production systems’. 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.
Agricultural professionals and growers have many questions about the benefits, drawbacks and other aspects of BDM. We have provided first-hand information on ‘BDM and fumigation’ to highlight that BDMs are not EPA-approved tarps for soil fumigation and should be only applied after the fumigant’s REI has expired. One frequently asked question is about the use of BDM in organic production. BDMs are allowed for organic production as long as they meet the criteria outlined by USDA National Organic Program, which is explained in our lecture slides. We have emphasized in our presentation slides that growers need to check with their certifier before applying any mulch product on their farm. To address the BDM economics question, our fact sheets demonstrate the cost comparison between the use of BDM, conventional plastic mulch and no-mulch. Growers can follow the format provided in the fact sheets and calculate the costs in their context for comparison, so they become aware of what is suitable on their farm. The majority of growers’ concerns have concentrated around the constituents of BDM as it is incorporated into the soil at the end of growing season. Our fact sheet provides detailed explanation on what is in a BDM along with percent composition and role of each constituent. Another fact sheet entitled ‘Glossary of terms associated with BDM for specialty crops’ enables growers to have a better understanding of the details associated with the mulch. All the information we have written is available through our website and bridges current information gaps regarding BDM. Here are a few comments on our curriculum from our colleagues and stakeholders:
- Thanks for your email! 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)
- Thank you Srijana and Carol for this valuable information. 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)
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, 10 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 that are used to make BDMs, and how the origin of these feedstocks are not the factor determining biodegradability of the BDM (e.g., just because a product is biobased does not mean it is biodegradable); (3) the use of GMOs in the fermentation process used to produce biobased polymers; (4) naturally occurring soil microorganisms and environmental conditions that 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 for mulch fragments (PE or BDM); (7) how to calculate the on-farm costs associated with BDM use; and (8) how to distinguish a BDM from a product that will not biodegrade (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)