Organic Specialty Vegetables Youbin Zheng, Dave Llewellyn, Yun Kong, - - PowerPoint PPT Presentation

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Organic Specialty Vegetables Youbin Zheng, Dave Llewellyn, Yun Kong, - - PowerPoint PPT Presentation

Oct 22, 2023 246 likes •585 views

High Tunnel Production of Organic Specialty Vegetables Youbin Zheng, Dave Llewellyn, Yun Kong, Martha Gay Scroggins, Rene Van Acker, Ralph Martin, Mary Ruth McDonald, W. David Lubitz and Evan Elford OMAFRA Content 1. Introduction 2. Results

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High Tunnel Production of Organic Specialty Vegetables

Youbin Zheng, Dave Llewellyn, Yun Kong, Martha Gay Scroggins, Rene Van Acker, Ralph Martin, Mary Ruth McDonald, W. David Lubitz and Evan Elford

OMAFRA

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Content

  • 1. Introduction
  • 2. Results
  • 3. How we did the research
  • 4. Lessons learned and some

take home messages

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Why High Tunnels?

  • Controlled environment plant production is

more resource efficient and with higher yield than field production; however the initial investment can be high…;

  • Extend growing seasons;
  • Prevent some weather related damage;
  • Grow specialty crops which are difficult to

grow in the field;

  • Can be used to reduce pests…;
  • Can be movable;
  • Light, humidity, Temperature can be

controlled to some extend;

  • ….
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SLIDE 4

Project History and Participants’ Expertise

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Huge difference between tunnel and field plants on July 23

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Cherry Tomato --Sarina Hybrid

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Yield loss of field tomato from animals, hail, and disease

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Bitter Melon—Canton Green F1

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Happier bitter melons in the warmer high tunnels

How many fruits have you found

  • n the

plant?

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Glebionis coronaria edible chrysanthemum Tonghao

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PEA PODS（China 6 snow pea)

200 400 600 800 1000 1200 Pod weight Pod number Cumulative yield (g m

  • 2 or No. m-2)

Open field High tunnel High tunnel+insect netting

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Pea shoot ‘HO LAN DOW’

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20 40 60 80 100 120 140 160 Open field High tunnel High tunnel+insect netting Pea shoots yield (g m-2)

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Intercropping

Oasis

Tong Hao

0.0 0.4 0.8 1.2 1.6 2.0 Open field High tunnel High tunnel+insect netting Tonghao yield (kg m-2)

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Transplanting dates

May 6-8，2015 Jun 3-4，2015

How we did the trials?

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Planting density

  • Bitter melon: 1.9 plants/m2
  • Tomato: 2.4 plants/m2
  • Pea pod: 15 plants/m2
  • Tonghao (edible mums): 15gseeds/m2
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Plant Management

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Lessons Learned

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End Walls

  • Careful construction is

essential to proper functioning and tight- fitting doors (jig)

  • Don’t scrimp on latch

hardware

  • Need for securing

propped-open doors on hot and windy days

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Winter Storage of Poly

  • Full roll-up sides is a unique design
  • Clean, on-site storage
  • Can be easily rolled down in spring

to begin warming/drying soil

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Environment Measurement and Control

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Average Temperatures

Field Unscreened Tunnel Screened Tunnel Air Temperature Season 19.3 20.2 21.7 Air Temperature June 17.5 19.1 20.4 Air Temperature July 20.3 21.1 22.9 Air Temperature August 19.1 19.7 21.1 Soil Temperature Season 18.9 20.0 21.0 Additional Degree Days for High Tunnels, Compared to Field (for 107 days – May 26 to Sep. 11, 2015) Unscreened Tunnel: 101 degree days Screened Tunnel: 259 degree days

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Soil Temperatures

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Solar Radiation

  • Average solar radiation (season):

– Field: 231 W/m2 – Unscreened: 171 W/m2 – Screened: 163 W/m2

  • Transmissivity of glazing ~ 70-75 %

– Complicated by presence of plants later in season.

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Early Season Frost Protection Inside Tunnels: Overnight May 13, 2015

  • 5

5 10 15 20 25 30

Temperature (°C)

Air inside tunnel Air under black tent Air under clear tent Soil under black tent Soil under clear tent

Δ 4.9 º C Δ 7.3 º C

Below - 2 º C for ~3 hr

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Summary

High tunnel improved crop yield possibly due to:

  • extended production period;
  • Reduced yield loss from disease, animals

and severe weather (e.g., hail, heavy rain);

  • Created a better microclimate for crop

production. More work is needed for environmental control and on other species

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THANKS

Katherine Vinson, Nora Alsafi, Patrick Kelly, Amy Kong and many more! BioFert Manufacturing Inc. DeCloet Greenhouse Manufacturing Ltd.