NC STATE UNIVERSITY
Modification of Microclimates in High
Tunnels: A case study at CEFS
Cary Rivard and Steve Moore
February 17th, 2009
High Tunnel Workshop
Center for Environmental Farming Systems
Microclimate Modification
High tunnels can provide:
• Frost protection
• Rain protection
• Solar energy retention
• Wind protection
Factors to consider:
• Ventilation
• Adequate drainage
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
Minimum Daily Temperature (degrees F)
90
80
Avg Field
Avg Tunnel
70
60
50
40
30
20
10
Easter freeze
33 deg F – Tunnel
24 deg F – Field
0
9-Mar
29-Mar
18-Apr
8-May
28-May
17-Jun
7-Jul
27-Jul
16-Aug
Daily Avg Temperature - CEFS 2007
100
Daily Average Temperature (degrees F)
90
Avg Field
Avg Tunnel
80
70
60
50
40
30
Tunnel
Planting
20
10
Field Planting
0
9-Mar
29-Mar
18-Apr
8-May
28-May
17-Jun
7-Jul
27-Jul
16-Aug
Maximum Air Temperature - CEFS 2007
140
Field
Tunnel
Field Planting
Daily Maximum Air Temperature
120
100
80
60
40
Tunnel
Planting
20
0
9-Mar
29-Mar
18-Apr
8-May
28-May
17-Jun
7-Jul
27-Jul
16-Aug
Soil Temperature - CEFS 2007
100
90
Field
Tunnel
Daily Avg Soil Temperature (degrees F)
80
70
60
50
40
Tunnel
Planting
30
20
Field Planting
10
0
9-Mar
29-Mar
18-Apr
8-May
28-May
17-Jun
7-Jul
27-Jul
16-Aug
CEFS 2008: Gray Leaf Spot
• Stemphylium spp.
–
–
–
–
Foliar leaf spot
Warm wet conditions
Wind / rain dispersal
Severe defoliation
CEFS 2008: Gray Leaf Spot
CEFS Main Effects - 2008
60
55
50
Tunnel
Field
% LAD - Gray Leaf Spot
45
40
35
30
25
20
15
10
5
0
13-Mar
2-Apr
22-Apr
12-May
1-Jun
21-Jun
11-Jul
31-Jul
20-Aug
Pesticide Retention
Field and High Tunnel Hornworm Populations Following Bt Spray
0.8
0.7
H o rn w o rm P o p u lat io n
0.6
0.5
High Tunnel
0.4
Field
=
Spraying of
Bt in High
Tunnel and Field
0.3
0.2
0.1
0
3-Jun
=
Spraying of Bt in
Field
7-Jun
11-Jun
15-Jun
19-Jun
23-Jun
27-Jun
1-Jul
Time
5-Jul
9-Jul
13-Jul
17-Jul
21-Jul
25-Jul
29-Jul
Soil Microclimate
• Soil ecosystems can be affected by tunnel
microclimate.
– Soil moisture
• Fluxations
– Temperature
• Solarization
– Physical characteristics
– Biological properties
– Salinity / Leaching
Removal of plastic for leaching
Soil Moisture - CEFS 2007
0.25
Field
Tunnel
= >.25” rain
Soil Water Content (m3/m3)
0.20
0.15
0.10
0.05
0.00
9-Mar
29-Mar
18-Apr
8-May
28-May
17-Jun
7-Jul
27-Jul
* - Modified
broken sensor
rep C of field.
Rain
eventsfor
increased
soil inmoisture
in the field
16-Aug
Soil Moisture - CEFS 2008
0.35
Daily Avg Soil Water Content
0.30
Field
Tunnel
0.25
0.20
0.15
0.10
0.05
0.00
8-Mar
28-Mar
17-Apr
7-May
27-May
16-Jun
6-Jul
26-Jul
Daily average soil mositure fluxuations
15-Aug
4-Sep
EFFECT
Systems Effects onSYSTEM
Fruit Quality
High Tunnel
vs.
Field System
Breakdown of Non-Marketable Fruit: CEFS, 2008
S. O’Connell (MS Thesis)
Systems Effects on Fruit Yield
Main System Effects: CEFS 2007
140
Tunnel
Field
120
100
80
60
25 days
40
20
Au
g
8-
Au
g
1-
l
25
-J
u
l
18
-J
u
l
11
-J
u
4Ju
l
27
-J
un
20
-J
un
13
-J
un
6Ju
n
ay
0
30
-M
Cumulative Total Yield (lbs/plot)
160
Planting Date
Planting Date
CEFS - 2007
180
160
120
100
21 days
80
60
40
20
8Au
g
1Au
g
Ju
l
25
-
Ju
l
18
-
Ju
l
11
-
ul
4J
Ju
n
27
-
Ju
n
20
-
Ju
n
13
-
un
6J
M
ay
0
30
-
Cumulative Total Yield (lbs/plot
140
03/20 - Tunnel
04/03 - Tunnel
04/19 - Tunnel
Planting Date
Planting Date in High Tunnels: CEFS - 2008
180
160
Total yield (lbs/plot)
140
4-Mar
18-Mar
17-Apr
120
100
80
60
40
20
0
2-May
12-May 22-May
1-Jun
11-Jun
21-Jun
1-Jul
11-Jul
21-Jul
31-Jul
10-Aug 20-Aug
Planting Date
Catfacing in Tunnel - CEFS 2007
0.60
Catfacing Incidence (by number)
0.50
20-Mar
3-Apr
19-Apr
0.40
0.30
0.20
0.10
0.00
18-May
0 10
28-May
7-Jun
17-Jun
27-Jun
7-Jul
17-Jul
27-Jul
6-Aug
16-Aug
Catfacing: Main Effects in Tunnel - CEFS 2007
Catfaced / Total Fruit Yield (by wt and number)
0.16
Fruit Weight
Fruit Number
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
20-Mar
3-Apr
19-Apr
Non
Self
Beaufort
Plant Date
Rootstock
Fruit Weight
P<0.01
NS
Fruit Number
P<0.01
NS
Maxifort
Soil Solarization
• Thermal inactivation
– Soilborne plant pathogens
– Insects
– Weeds
• Efficacy
– Temperature
– Exposure time
– Soil Depth
(Katan et al., 2003)
2007 Solarization: Maximum Temperatures
160
140
120
100
80
60
40
20
Field Air (F)
Field Soil (F)
Tunnel Air (F)
Tunnel Soil (F)
0
23-Aug
28-Aug
2-Sep
7-Sep
Temperature (F)
12-Sep
17-Sep
2007 Solarization: Minimum Temperatures
100
90
80
70
60
50
40
30
20
10
Field Air (F)
Field Soil (F)
Tunnel Air (F)
Tunnel Soil (F)
0
23-Aug
28-Aug
2-Sep
7-Sep
Temperature (F)
12-Sep
17-Sep
2007 Solarization: Daily Avg Temperatures
120
100
80
60
40
20
Field Air (F)
Field Soil (F)
Tunnel Air (F)
Tunnel Soil (F)
0
23-Aug
28-Aug
2-Sep
7-Sep
Temperature (F)
12-Sep
17-Sep
Winter Microclimate
•
•
•
•
Cover crops
Winter vegetable production
Will tunnel microclimate allow for both?
Leaching / fallow period
Rye/Vetch cover crops inside the high tunnel
CEFS 2009: Daily Minimum Temperature
50
45
Field
Tunnel
Air Temperature (F)
40
35
30
25
20
15
10
5
0
12-Jan
17-Jan
22-Jan
27-Jan
1-Feb
6-Feb
CEFS 2009: Daily Maximum Temperature
100
90
Field
Tunnel
Air Temperature (F)
80
70
60
50
40
30
20
10
0
12-Jan
17-Jan
22-Jan
27-Jan
1-Feb
6-Feb
CEFS 2009: Daily Average Temperature
70
Air Temperature (F)
60
Field
Tunnel
50
40
30
20
10
0
12-Jan
17-Jan
22-Jan
27-Jan
1-Feb
6-Feb
Cover Crops
Biomass (lbs/acre)
Available N
C:N
Rye
Vetch
(lbs/acre)
High Tunnel
3749.4
329.4
9.8
83.2
Field
721.8
1589.1
8.5
54.2
Discussion
• 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?
Questions