HANDLE WITH CARE: Biodegradable Mulch Handling and Cleaning

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HANDLE WITH CAREBiodegradable Mulch Handling
and Cleaning

• Jeremy S. Cowan
• Department of Horticulture and Landscape
  Architecture, Washington State University,
• WSU Mount Vernon NWREC, 16650 State Route 536,
  Mount Vernon, WA 98273

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Mount Vernon, Washington field site, July 23,
2010
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Evaluating Biodegradable Plastic Mulches for Use
in High Tunnel Tomato Production in Western
Washington

• Effects of BDM on tomato yield and fruit quality
• oBrix, 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

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Crop Yield Fruit Quality Assessments

• Marketable fruit (USDA grading) for fresh tomato
  average weight and total fruit count
• Unmarketable fruit categorized by
  predominantdisorder or disease
• Fruit quality assessments include
• Juice content
• Soluble solids (Brix)
• pH titratable acidity
• Lycopene and ß-carotene
• Ascorbic acid

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Table 1. Comparison of tomato yield in each field
location (HT and OF) in Washington in 2010.
Location Total No. Total Wt. (Kg) Mrkt. No. Mrkt. Wt. (kg) Unmrkt. No. Unmrkt. Wt. (kg) Mrkt. No. Mrkt. Wt. (kg)
High Tunnel 72.67 a 18.67 a 14.96 a 3.50 a 57.54 a 15.07 a 20.67 a 19.00 a
Open Field 14.04 b 1.98 b 0.58 b 0.07 b 13.46 b 1.91 b 4.08 b 3.67 b
LSD (.05) lt.0001 0.0009 0.0004 0.0014 lt.0001 lt.0001 0.0013 0.0016
Table 2. Comparison of tomato yield by mulch
treatment in Washington in 2010
Mulch Total No. Total Wt. (kg) Mrkt. No. Mrkt. Wt. (kg) Unmrkt. No. Unmrkt. Wt. (kg) Mrkt. No. Mrkt. Wt. (kg)
BioBag 51.13 a 12.49 a 7.00 1.53 43.88 a 10.95 a 8.88 b 7.75 a
BioTelo 49.63 a 12.02 a 7.50 1.77 42.13 a 10.26 a 10.13 b 9.00 a
Spunbond 39.00 b 9.01 b 8.25 1.97 30.50 c 7.08 c 13.38 b 12.75 ab
Black Plastic 43.13 ab 10.14 ab 4.75 1.04 38.00 ab 9.09 ab 8.00 b 7.25 a
Bareground 34.38 b 8.30 b 11.13 2.66 23.25 d 5.31 d 20.25 a 18.88 b
Cellulose Control 42.88 ab 9.99 ab 8 1.74 35.25 bc 8.25 bc 13.63 b 12.38 ab
LSD (.05) 0.0139 0.0321 NS NS lt.0001 lt.0001 0.0006 0.0038
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SB PLA
Cellulose
Notice the tenting of SB PLA mulch and edge
degradation of cellulose mulch at soil interface.
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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
Material Degradation AUDPC
High tunnel  
BioBag 112 bc
BioTelo 148 b
Spunbond 0 c
Black Plastic 44 bc
Cellulose Control 398 a
P (0.05) 0.0001
Open field  
BioBag 200 y
BioTelo 208 y
Spunbond 82 y
Black Plastic 103 y
Cellulose Control 1556 x
P (0.05) 0.0001
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Image-based Analysis of BDM Degradation

• 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

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Mulch Treatment Degradation Biodegradation
Assessments

• 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

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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?

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Theoretical Framework

• Neoclassical Economic Theory
• Diffusion of Innovations
• Bourdieus Theory of Capital
• Forms of Cultural Capital
• Epistemic Barriers

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Current Status

• Year 1 complete
• Year 2
• Tunnels are up
• BDMs 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

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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