HANDLE WITH CARE: B IODEGRADABLE M ULCH H ANDLING AND C LEANING Jeremy S. Cowan Department of Horticulture and Landscape Architecture, Washington State University, WSU Mount Vernon NWREC, State Route 536, Mount Vernon, WA 98273

Mount Vernon, Washington field site, July 23, 2010

Evaluating Biodegradable Plastic Mulches for Use in High Tunnel Tomato Production in Western Washington  Effects of BDM on tomato yield and fruit quality  o Brix, Acidity, pH, Firmness, *Ascorbic Acid, *Lycopene  Visual ratings of BDM degradation and image analysis  Calibrate visual assessments w/ image analysis and compare with physical properties to determine efficacy for measuring loss of BDM integrity  Potential Barriers to Adoption  Demonstration plots, field days, focus groups, surveys

Crop Yield & Fruit Quality Assessments  Marketable fruit (USDA grading) for fresh tomato: average weight and total fruit count  Unmarketable fruit categorized by predominant disorder or disease  Fruit quality assessments include:  Juice content  Soluble solids (Brix)  pH & titratable acidity  Lycopene and β-carotene  Ascorbic acid

Table 1. Comparison of tomato yield in each field location (HT and OF) in Washington in Table 2. Comparison of tomato yield by mulch treatment in Washington in 2010

Notice the tenting of SB PLA mulch and edge degradation of cellulose mulch at soil interface. SB PLA Cellulose

Table 3. Comparison of area under mulch degradation progress curve (AUDPC) values among mulch treatments by field location (HT and OF) in Washington in 2010

 Digital imaging of mulch samples  Transformation to monochromatic images  Histogram of luminosity is obtained  Compare area under histogram curves of BDM samples at Times 1 – 3 with visual assessments and physical properties data to establish correlation coefficients Image-based Analysis of BDM Degradation

 BDM samples collected & analyzed upon receipt from manufacturer (Time 0), at mulch laying (Time 1), at first flower (Time 2), and at final harvest (Time 3)  Evaluating primary physical/ structural characteristics by measuring:  Thickness  Weight  Tensile strength  Elongation  Tearing strength Mulch Treatment Degradation & Biodegradation Assessments

The Question If biodegradable plastic mulches provide both environmental benefits (no landfilling or burning) and economic benefits (one study reports a 25% cost savings) then why are farmers slow to adopt in the United States, specifically Western Washington? And, how might an opportunity to see degrading mulches affect growers perceptions?

Theoretical Framework  Neoclassical Economic Theory  Diffusion of Innovations  Bourdieu’s Theory of Capital  Forms of Cultural Capital  Epistemic Barriers

Current Status  Year 1 complete  Year 2  Tunnels are up  BDM’s are laid  Inside tomatoes planted  Protocols for image analysis being developed  Light box designed and under construction  Experimental design for adoption study under development  Demonstration plots are being planned

Many Thanks to:  Carol Miles  Karen Leonas  Debbie Inglis & Babette Gunderson  Jonathan Roozen, Karen Hasenoehrl, and the MV Veg Hort Team and Grad Students  Hang Liu and the Leonas’ Lab