e valuating b iodegradable m ulches for h igh t unnel t omato p roduction : a m ulti - faceted a...
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EVALUATING BIODEGRADABLE
MULCHES FOR HIGH TUNNEL TOMATO PRODUCTION:
A MULTI-FACETED APPROACH Jeremy S. Cowan
Department of Horticulture and Landscape Architecture, Washington State University, WSU Mount Vernon NWREC, 16650 State Route 536,Mount Vernon, WA 98273
Evaluating Biodegradable Plastic Mulches for Use in
High Tunnel Tomato Production
Effects of BDM on tomato yield and fruit quality oBrix, Juice, Acidity, pH, Firmness, *Phenolics,
*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
Post-tillage degradation in the soil Using photographic image analysis to measure
number and size of mulch fragments in the soil every 3 months
Fruit Quality Assessments
Measurement High Tunnel Open Field P-value
Juice 94.40 a 94.08 b 0.0080
oBrix 4.72 b 4.98 a 0.0007
pH 4.17 a 4.09 b 0.0330
Acidity 0.364 b 0.404 a 0.0001
Lycopene 10.8 a 8.2 b 0.0008
No significant mulch effect in 2011 on any fruit quality parameter
No location effect on firmness or β-carotene
Table 1. Comparison of tomato yield in each field location (HT and OF) in Washington in 2011.
Table 2. Comparison of tomato yield by mulch treatment in Washington in 2011
Location Total No. Total Wt. (kg)Marketable %
(No.)Marketable %
(kg)
High Tunnel 88.5 a 25.6 a 57.3 59.4
Open Field 20.8 b 4.1 b 49.3 51.8
P = (0.05) 0.0007 0.0041 0.1224 0.2367
Mulch Total No. Total Wt. (kg)Marketable %
(No.)Marketable %
(kg)
BioBag 56.5 a 15.2 a 46.6 bc 50.0 b
BioTelo 62.3 a 16.5 a 49.0 b 50.4 b
Spunbond 47.8 b 13.9 b 52.8 b 54.2 b
Black Plastic 59.8 a 15.8 a 36.5 c 38.6 c
Bareground 55.3 ab 15.1 ab 68.7 a 71.7 a
WeedGuardPlus 46.6 b 12.7 b 66.4 a 68.5 a
P = (0.05) 0.0036 0.0259 <0.0001 <0.0001
Rips, tears, and holes are counted twice monthly and apercent rating assigned based on exposed soil
Mulch Visual Assessments
Table 3. Comparison of area under mulch degradation progress curve (AUDPC) values in Washington in 2011
Treatment% Degradation
AUDPCLocation
High Tunnel 357 b
Open Field 1367 a
P = (0.05) 0.0002
Mulch
BioBag 927 b
BioTelo 966 ab
WeedGuardPlus 2220 a
Spunbond 85 d
Black Plastic 112 c
P = (0.05) <0.0001
Digital imaging of mulch samplesTransformation to monochromatic
imagesHistogram of luminosity is obtainedCompare 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
Soil sampling (known volume) every 3 months
Mulch fragments removed by hand and using sieves
Cleaned samples photographedUse ImageJ (NIH) to count and
measure mulch fragments to obtain average number and size per volume soil
Image-based Analysis of Post-tillage Degradation
Current StatusYear 1 completeYear 2
Photographing BDM samplesMeasuring fruit total phenolicsTill-down sampling - ongoing
Year 3Protocols for image analysis being
refinedPlanning field season
Many Thanks to:Carol MilesKaren Leonas, Debbie Inglis, Preston
Andrews, & Jessica GoldbergerJonathan Roozen, Babette
Gunderson, Karen Hasenoehrl, and the MV Veg Hort Team and Grad Students
Hang Liu and the Leonas’ LabThe rest of the SCRI Team