Use of Biodegradable Mulch for Vegetable Crop Production

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Use of Biodegradable Mulch for Vegetable Crop
Production

• M. D. Orzolek
• Dept. of Horticulture
• The Pennsylvania State University

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Non-degradable plastic film - 1.0 mil
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Different mulch colors-ND
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Silver/black on continuous raised beds
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Retrieved ND plastic film - What to do with it ?
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ND mulch residue after 10 years applied in the
field
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Burning plastic mulch in field ??

• Polyethylene melts and not incinerates below
  temps of 1,000 F.

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PlastoFuel condensed ag plastics
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PlastoFuel

• PlastoFuel is made by condensing ag and consumer
  polyethylene and polypropylene plastics. It was
  developed at Penn State by Garthe Lemont and
  Orzolek. It was tested in a Korean burner that
  changed the plastic from a solid to liquid to gas
  and incinerated _at_ 2,000F.

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Burner which incinerated plastics
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Degradable Plastic

• Mid-1970s British and American scientists
  discover biodegradable plastic derived from
  cornstarch.
• In 1996, four percent of all plastic production
  was biodegradable at a cost of 2 to 3/pound
  compared to 0.50/pound for nondegradable plastic.

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Photodegradable Plastic

• Mid 1980s photodegradable plastic mulch was
  developed but was very unpredictable in timing of
  initial degradation. The plastic mulch has to be
  completely intact for minimally 30 days for crop
  response.

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Early plastic degradation prior to crop maturity
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Biodegradable Mulch

• Grower considerations
• Degrades in field - no retrieval
• Multiple colors available
• Higher product cost compared to non-degradable
  mulch
• Variable widths available - 3 to 5.

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Trial Specifics

• Crops
• 2005/06/07/08
• Bell pepper,cantaloupe, and eggplant.

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Field Design

• 3 replications
• 12 plants per treatment
• In-row-spacing 2 and between row spacing 6 to
  8.
• All crops were established from locally grown
  transplants.

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Field Observation -7/22/05

• All biodegradable mulch colors were brittle with
  longitudinal cracks (tears) in plastic.
  Approximately 10 to 15 of soil visible on
  raised bed. Currently, few if any weeds in row
  with crops.

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Longitudinal tear in mulch

• Mulch may tear during application in the field.

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Degradation of mulch along soil line

• Biodegradable mulch will initially degrade along
  soil line on shoulder of bed.

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Field Observation -10/20/05

• Retrieved non-degradable black and blue plastic
  mulch and drip tape from field. Biodegradable
  mulch colors were approximately50 to 60
  degraded.

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Biodegradable Mulch
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Field Observation - 7/12/06

• The brown BD mulch appeared to be degrading
  faster than either the black or green BD. Less
  mulch breakdown with melon crop compared with
  pepper crop. No difference in crop growth
  between non-degradable and biodegradable plastic
  mulches.

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Field Observation - 8/24/06

• On the average, 30 to 50 of soil was visible in
  beds where BD mulch had degraded. Significant
  weed growth observed in row when soil was not
  covered with plastic mulch.

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2005 Marketable Pepper Yield
Mulch type fruit Wt. fruit-lbs. Avg.fruit wt. - oz.
ND black 30.0 11.9 6.3
ND blue 9.0 2.6 4.6
BD black 39.7 12.8 5.2
BD brown 44.3 14.5 5.2
BD green 29.0 9.5 5.2
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2006 MarketablePepper Yield
Mulch type Fruit Wt. fruit lbs. Avg. fruit wt. - oz.
ND black 38.7 18.4 7.6
ND IRT 22.0 9.4 6.8
BD black 24.7 10.5 6.8
BD brown 25.0 11.7 7.5
BD green 31.7 13.9 7.0
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2007 Marketable Pepper Yield
Treatment of fruit Wt. fruit lbs. Avg. fruit wt. (oz)
No plastic 47.3 18.8 6.3
ND film 96.0 38.9 6.5
BD film - thin 73.3 31.0 6.8
BD film - thick 74.3 31.3 6.7
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2008 Pepper Trial
Mulch Fruit Wt. - lbs. /plant
MTX25 93.7 36.0 7.8
ND poly 107.3 41.1 8.9
Biotelo 86.0 30.3 7.2
MTX35 108.0 39.9 9.0
MTX32 97.0 36.7 8.1
Bare soil 57.0 15.9 4.8
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2005 Marketable Melon Yield
Mulch type Fruit Wt. fruit Lbs. Avg. fruit Wt. - lbs.
ND black 19.3 53.6 2.8
ND blue 20.0 64.6 3.2
BD black 20.0 68.3 3.4
BD brown 13.7 44.6 3.3
BD green 16.7 43.8 2.6
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2006 MarketableMelon Yield
Mulch type Fruit Wt. fruit Lbs. Avg.fruit Wt. - lbs.
ND black 18.3 76.9 4.2
ND IRT 25.3 79.0 3.1
BD black 16.7 56.0 3.4
BD brown 18.7 64.2 3.4
BD green 17.3 42.3 2.4
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2008 Melon trial
Mulch fruit Wt. - lbs. Avg.wt
MTX25 17.3 58.7 3.4
ND poly 21.0 92.3 4.4
Biotelo 15.0 74.9 5.0
MTX35 17.0 75.1 4.4
MTX32 13.3 41.1 3.1
Bare soil 11.0 42.4 3.9
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2008 Field Trials
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2008 Field Trials
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2008 Field Trials
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2008 Eggplant Trial
Mulch fruit Wt.-lbs. /plant
MTX25 51.0 38.0 6.4
ND poly 68.0 48.0 8.5
Biotelo 46.7 34.9 5.8
MTX35 48.7 36.2 6.1
MTX32 59.0 40.8 7.4
Bare soil 18.0 12.6 2.3
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Soil Temp - 7/14 at 100pm - 2 below soil
Mulch Temp-F
MTX25 97.5
ND poly 93.8
Biotelo 91.1
MTX35 98.8
MTX32 97.9
Bare soil 80.4
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Conclusions from study

• Yield of both pepper and cucurbit fruit from
  plants grown on biodegradable plastic mulch is
  equal to or sometimes higher compared to pepper
  and cucurbit crops grown on non-degradable
  plastic mulch.

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Conclusions from study

• Biodegradable (BD) plastic mulch does not have to
  be retrieved from field, but can be incorporated
  with a rototiller or disk in the fall.
• It appears that BD mulch will start to degrade
  about 45 to 50 days after laying the mulch in the
  field.

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Incorporating biodegradable plastic mulch-9/23/08
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Conclusion from study

• Response of various vegetables to mulch color
  similar in both non-degradable and biodegradable
  plastic mulch.

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Conclusions from study

• Under dry or drought conditions, the rate of
  degradation of BD plastic mulch is slower
  compared to growing seasons with weekly rainfall.
• If BD mulch degrades earlier than 45 days, weed
  populations may be very competitive with crop -
  exception 2008 field study.

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Grower considerations with BD mulch

• Initial cost of roll of BD plastic mulch about
  50 higher than ND mulch.
• Currently, rolls of BD mulch available in 3,
  4,or 5 foot widths.

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Any questions?

• from audience