how to obtain a high tomato yield - ep heuvelink
DESCRIPTION
TRANSCRIPT
How to obtain a high tomato yield100 kg per m2 per year or more ?
Ep HeuvelinkHorticultural Supply Chains, www.hpc.wur.nl/uk
Plant Sciences Group, Wageningen University
1st Agriconference on Tomatoes from Morocco9 December 2009, Agadir, Morocco
Yield development (Netherlands)
Sweet pepper
Cucumber
Tomato
+ 96%
+ 117%
+ 34%
Sweet pepper
Cucumber
Tomato
0
20
40
60
80
1980 1990 2000 2010
Year
Yie
ld (
kg m
-2)
+107%
+94%
+125%
Cucumber
Tomato
Sweet PepperTomato in Morocco
(Kwantitatieve Informatie voor de Glastuinbouw (KWIN 2008))
What factors are important for high yield ?� Greenhouse technology (e.g. light transmission)
� Cultivation techniques (e.g. high wire system, rootstocks)
� Modern cultivars
� Greenhouse climate control(temperature, CO2, humidity, supplementary light)
� Most recent developments(semi~closed greenhouses, diffuse light)
Also important is:
� High education level of growers
� Moderate climate: winters not too cold, summers not too hot
Nor
thNor
thse
ase
a
Obtain high light transmissivity of the greenhouse� 1% more light ≈ 1% more yield
� Greenhouse transmissivity in 1980 ≈ 65% nowadays ≈ 78%
represents about 20% yield increase
� Large glass panes, small construction parts, white !
Cultivation techniques� High wire system; same plant almost year-round� Long season, up to 50 weeks; no production gaps
Cultivation techniques� Stonewool + drippers; better control of root environment
� Extra stems in summer (2.5 plants m-2 → 3.8 stems m-2)� Use of grafted plants (cultivar on rootstock)
StonewoolStonewool
CubeCube & Slab& Slab
0.0 1.0 2.0 3.0 4.0
Leaf Area Index
0.0
0.2
0.4
0.6
0.8
1.0F
ract
ion
light
inte
rcep
ted
y = 1 - e -k LAI
Influence of Leaf Area Index (LAI) on the fraction of light intercepted
by a tomato crop (k = extinction coefficient = 0.8)
LAI: mLAI: m22 green leaf area per mgreen leaf area per m22 ground area)ground area)
Measured LAI throughout the season for tomato(measurements at modern commercial farms)
0
1
2
3
4
5
50 100 150 200 250
Day of year
Leaf
Are
a In
dex
(m2 m
-2)
Year 2003
Year 1990
� Now much higher than in early nineties, probably becauseextra side shoots are retained from spring onwards + rootstock?
Effect of cultivar on tomato yield (Spring crop)
40% yield increase since 1950, mainly because of higher light use efficiency
Greenhouse climate
� Modern climate computers makemore accurate control possible
� Important factors: temperature, CO2, humidity
• Heating
→ boiler + hot water pipes
• Cooling
→ vents in roof
→ fog cooling
→ roof cooling
Production techniques in modern greenhouses (1)Greenhouse climate: temperature
Fruit weight (dry mass) and
fruit growth period (FGP) tomato
Temperatuur (oC) Gewicht (g) Uitgroeiduur (d)17 4.8 7419 4.3 6321 3.2 5623 2.7 50
Source: A.N.M. de Koning
At lower temperature harvest starts later and fruits are more heavy
Temperature (oC) Fruit weight (g) FGP (d)
High temperature stress (tomato)
� No effect on total growth
� Poor fruit set
� Cause: bad pollen, poorly released 0
4
8
12
16
Controle Hoge Temp
Aan
tal g
ezet
te v
ruch
ten
p
er p
lan
t
0
20
40
60
80
100
Controle Hoge Temp
Lev
end
e st
uif
mee
lko
rrel
s (%
)
Control: 28/22oC D/N; High temp. 32/26oC
Source: Sato et al. 2006
� Questions like: is 1 h 36oC a problem? Or: Is 1 h 38oC same as 10 h 36oC?
Not yet clear !
Control High temp.
Control High temp.Via
ble
polle
n (%
)N
umber
of se
t fr
uits
per
pla
nt
AlsoAlso tootoo low low temperaturestemperatures limit fruit set !limit fruit set !
Greenhouse climate: CO2
� Natural gas for heating: flue gasses for CO2
� Pure CO2
Source: E. Nederhoff
Rule of thumb for CO2 effect:
For each 100 ppm increase in CO2 % increase in growth can be calculated as
1500 × 1000
CO2 × CO2
� From 350 to 450 ppm: 12% growth increase
� From 600 to 700 ppm: 4% growth increase
� From 1000 to 1100 ppm: 1.5% growth increase
� But from 350 to 250 ppm: 19% reduction in growth!!
Source: E. Nederhoff, 1994
Greenhouse climate: High humidity
Deficit < 0.2 kPa (<1.5 g/m3) or RV >94% at 25°C
� Too low Ca in leaves KK> smaller leaves KK> less light interception KK> less photosynthesis
� Pollination less optimal (without bumble bees)
� Higher disease risk (botrytis)
� Higher risk fruit “disorders”(cracking)
Greenhouse climate: Low humidity
Deficit > 1 kPa (>7.5 g/m3) or RH < 70% at 25°C
� Water stress in plant
� Stomata close
� Cell elongation reduced KK> smaller, thicker leaves
� Less photosynthesis
� Reduced water content fruit
� BlossomKendKrot (BER)
New trends: semiKclosed greenhouse
AirAir--conditioned (active cooling) so vents more closedconditioned (active cooling) so vents more closed
Too high temperatures can be avoidedToo high temperatures can be avoided
Higher COHigher CO22 levels levels �� higher yieldshigher yields
In the Netherlands: Winter: 80% diffuse radiationSummer: 60% diffuse radiation
Advantages of diffuse radiation:� More even distribution of light (horizontally; no shadows)� Light penetrates deeper in the crop� Lower risk of light saturation� Mild micro-climate
New trends: Diffusing cover materials
Control Low diffuse High diffuse
Haze 0% 30% 70%
Transmission 83% 83% 80%
New trends: Diffusing cover materials
Experiment with cucumber crop: Bleiswijk 2008, Netherlands
Diffuse light: 9% higher cucumber production
(crop planted in March)
0
25
50
75
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30Weeks
Cum
ulat
ief p
rodu
ctie
(kg/
m2)
Hoog diffuus
Laag diffuus
Controle
+9.2%
+6.5%
Weeks
Pro
duc
tion
(kg m
K2)
Source: T. Dueck
High diffuse
Low diffuse
Control
Conclusion: main reasons for high tomato yield� Almost yearround cultivation
(high wire system, extra stems in summer, rootstocks)
� Cultivation out of soil
� Hightech greenhouses (high light transmissivity,good temperature and CO2 control)
� High yielding cultivars (breeding)
Future developments: semiKclosed, LED lights
Thank you for your attention
The following colleagues contributed to this presentation:
Menno Bakker, Silke Hemming, Leo Marcelis, Anke van der Ploeg