modification of microclimates in high tunnels: a...

NC STATE UNIVERSITY

Cary Rivard and Steve Moore

February 17th, 2009High Tunnel Workshop

Center for Environmental Farming Systems

Modification of Microclimates in High Tunnels: A case study at CEFS

High tunnels can provide:

• Frost protection

• Rain protection

• Solar energy retention

• Wind protection

Factors to consider:

• Ventilation

• Adequate drainage

Microclimate Modification

Photo courtesy: S. O’Connell (NCSU)

How many modifications of microclimate do you see?

Tunnel / Grafting Research

Environmental Monitoring

How many modifications of microclimate do you see?

Key Questions• What are the thermal dynamics of field and high

tunnel production?– Air and soil temperature

• Does reduced leaf wetness reduce foliar disease?

• How is the soil microclimate affected by tunnel production?– Soil moisture

• How does the microclimate affect fruit yield and quality?– Planting date

• How effective is solarization in tunnels?• Can we utilize microclimates for cover crops?

Minimum Temperature - CEFS 2007

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9-Mar 29-Mar 18-Apr 8-May 28-May 17-Jun 7-Jul 27-Jul 16-Aug

Min

imum

Dai

ly T

empe

ratu

re (d

egre

es F

)

Avg FieldAvg Tunnel

Easter freeze33 deg F – Tunnel24 deg F – Field

Daily Avg Temperature - CEFS 2007

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Dai

ly A

vera

ge T

empe

ratu

re (d

egre

es F

)

Avg FieldAvg Tunnel

Field Planting

Tunnel Planting

Maximum Air Temperature - CEFS 2007

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120

140


Dai

ly M

axim

um A

ir Te

mpe

ratu

re

FieldTunnelField Planting

Tunnel Planting

Soil Temperature - CEFS 2007

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Dai

ly A

vg S

oil T

empe

ratu

re (d

egre

es F

)

FieldTunnel

Field Planting

Tunnel Planting

• Stemphylium spp.– Foliar leaf spot– Warm wet conditions– Wind / rain dispersal– Severe defoliation

CEFS 2008: Gray Leaf Spot

CEFS Main Effects - 2008

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13-Mar 2-Apr 22-Apr 12-May 1-Jun 21-Jun 11-Jul 31-Jul 20-Aug

% L

AD

- G

ray

Leaf

Spo

t

TunnelField

CEFS 2008: Gray Leaf Spot

Field and High Tunnel Hornworm Populations Following Bt Spray

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3-Jun 7-Jun 11-Jun 15-Jun 19-Jun 23-Jun 27-Jun 1-Jul 5-Jul 9-Jul 13-Jul 17-Jul 21-Jul 25-Jul 29-Jul

Time

Hor

nwor

m P

opul

atio

n

High Tunnel

Field

=Spraying of Bt in High Tunnel and Field

=Spraying of Bt in Field

Pesticide Retention

Soil Microclimate

• Soil ecosystems can be affected by tunnel microclimate.– Soil moisture

• Fluxations

– Temperature• Solarization

– Physical characteristics

– Biological properties

– Salinity / LeachingRemoval of plastic for leaching

Soil Moisture - CEFS 2007

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0.25


Soil

Wat

er C

onte

nt (m

3/m

3)

FieldTunnel

* - Modified for broken sensor in rep C of field.

= >.25” rain

Rain events increased soil moisture in the field

Soil Moisture - CEFS 2008

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8-Mar 28-Mar 17-Apr 7-May 27-May 16-Jun 6-Jul 26-Jul 15-Aug 4-Sep

Dai

ly A

vg S

oil W

ater

Con

tent

FieldTunnel

Daily average soil mositure fluxuations

Breakdown of Non-Marketable Fruit: CEFS, 2008

SYSTEM EFFECT

High Tunnel vs. Field System

Systems Effects on Fruit Quality

S. O’Connell (MS Thesis)

Main System Effects: CEFS 2007

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30-M

ay

6-Jun

13-Ju

n

20-Ju

n

27-Ju

n

4-Jul

11-Ju

l

18-Ju

l

25-Ju

l

1-Aug

8-Aug

Cum

ulat

ive

Tota

l Yie

ld (l

bs/p

lot)

TunnelField

25 days

Systems Effects on Fruit Yield

Planting Date

CEFS - 2007

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30-M

ay

6-Jun

13-Ju

n

20-Ju

n

27-Ju

n

4-Jul

11-Ju

l

18-Ju

l

25-Ju

l

1-Aug

8-Aug

Cum

ulat

ive

Tota

l Yie

ld (l

bs/p

lot

03/20 - Tunnel04/03 - Tunnel04/19 - Tunnel

Planting Date

21 days

Planting DatePlanting Date in High Tunnels: CEFS - 2008

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2-May 12-May 22-May 1-Jun 11-Jun 21-Jun 1-Jul 11-Jul 21-Jul 31-Jul 10-Aug 20-Aug

Tota

l yie

ld (l

bs/p

lot)

4-Mar18-Mar17-Apr

Catfacing in Tunnel - CEFS 2007

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18-May 28-May 7-Jun 17-Jun 27-Jun 7-Jul 17-Jul 27-Jul 6-Aug 16-Aug

Cat

faci

ng In

cide

nce

(by

num

ber)

20-Mar3-Apr19-Apr

Planting Date

Catfacing: Main Effects in Tunnel - CEFS 2007

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0.02

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20-Mar 3-Apr 19-Apr Non Self Beaufort Maxifort

Plant Date Rootstock

Cat

face

d / T

otal

Fru

it Yi

eld

(by

wt a

nd n

umbe

r)Fruit WeightFruit Number

NSP<0.01Fruit Number

NSP<0.01Fruit Weight

Soil Solarization

• Thermal inactivation– Soilborne plant pathogens– Insects– Weeds

• Efficacy– Temperature– Exposure time– Soil Depth

(Katan et al., 2003)

2007 Solarization: Maximum Temperatures

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23-Aug 28-Aug 2-Sep 7-Sep 12-Sep 17-SepTemperature (F)

Field Air (F)Field Soil (F)Tunnel Air (F)Tunnel Soil (F)

2007 Solarization: Minimum Temperatures

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2007 Solarization: Daily Avg Temperatures

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Rye/Vetch cover crops inside the high tunnel

Winter Microclimate

• Cover crops• Winter vegetable production• Will tunnel microclimate allow for both?• Leaching / fallow period

CEFS 2009: Daily Minimum Temperature

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12-Jan 17-Jan 22-Jan 27-Jan 1-Feb 6-Feb

Air

Tem

pera

ture

(F)

FieldTunnel

CEFS 2009: Daily Maximum Temperature

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Air

Tem

pera

ture

(F)

FieldTunnel

CEFS 2009: Daily Average Temperature

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Air

Tem

pera

ture

(F)

FieldTunnel

Cover Crops

54.28.51589.1721.8Field

83.29.8329.43749.4High Tunnel

(lbs/acre)VetchRye

Available NC:N

Biomass (lbs/acre)

• Will tunnels provide enough season extension for successful double-cropping?

• Can we find cover crops that can be squeezed between summer and winter crops?

• How can we predict night time temperatures?

• What dynamics do air temperature have on crop growth?

Discussion

Questions

modification of microclimates in high tunnels: a...

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