Closed growing systems in the Netherlands towards a sustainable horticulture

1
Closed growing systems in the Netherlandstowards
a sustainable horticulture

• Wim Voogt Jop Kipp

Applied Plant Research PPO division Greenhouse
horticultre Naaldwijk The Netherlands
2
Content

• History
• Developments
• Soil-les systems
• (Soil grown crops)
• Bottle necks
• Developments

3
Protected horticulture

• High yields
• High fertiliser inputs

4
Fertiliser use in protected horticulture
5
The problem
Nutrient efficiencies of cropping systems
6
So 40 50 of the N-input is lost and moves
into environment
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Water Pollution Act

• discharge decree glasshouse horticulture (1994)
• Obligatory
• Rainwater collection basin, 500 m3/ha
• Closed growing system (except orchids)
• Soil crops, reuse of drainage water

8
Regulations

• Basically discharge of drainage water to surface
  water is prohibited
• Residual water only discharge to sewage system
• Salt accumulation, discharge allowed if Na gt
  defined value
• With calamities (disease outbreak), discharge
  only on permission

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Result

• New greenhouses all with closed systems
• Existing greenhouses change over to closed
  systems period 1994 1999
• Problems with technical lay-out
• Problems with water quantity / quality
• Problems with crop development
• Problems with control of regulations

10
Convenant Glasshosue Industry and Environment
(GLAMI)

• Partners
• Growers,
• Minstry of Agriculture nature and food quality,
• Ministry of Transport and communications
• Ministry of economic affairs
• Ministry of spatial planning, housing and the
  environment
• Municipalities
• Polder boards

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Decree glasshouse horticulture

• Covers all other regulations on water,
  fertilisers, energy and Plant Protection
  Chemicals.
• Aim Integral Environmental Task,
• reduction in use of energy
• reduction emission and residues of pesticides
• reduction of N and P emission
• Targets for 2010
• Consumption of Energy, PP-chemicals, N and P
  fertilisers

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Fertilisers

• Targets for N and P consumption 2000 - 2010
• Total input (manure, organic, chemical
  fertiliser)
• Specified per crop
• Lineair reduction from 2000 - 2010

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Targets for max consumption kg ha-1 yr-1
1985 2000 2010 N P N P N P Total
fertiliser supply 1826 220 1043 156 911 182 Crop
uptake 772 159 815 140 858 178Denitrification 219
- 41 - 6 -Emission 835 61 187 16 47 4
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Examples of target values N kg/ha P
kg/ha Crop 2000 2010 2000 2010 Gerbera 1550 1270 1
92 174 Rose 1460 1124 236 221 Chrysanthemum 1049 7
32 123 114 Carnation 865 781 162 157 Alstroemeria
675 535 153 150 Freesia 575 435 90 88 Amaryllis 41
0 354 75 71 Orchid 232 190 53 48
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Developments soil-les systems

• 1 open systems
• Rockwool slabs free drainage of leachate
• Potting plants open drainage
• substrate beds

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Bottle- necks

• Restricted Root Volume
• 10 - 15 l m-2
• Restricted quantity water and nutrients
• 2 - 5 of total demand
• Adequate water and nutrient supply !

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Bottle - necks 2

• Heterogeneity in crop growth / transpiration
• Heterogeneity in water supply (drip - irrigation)

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Measured crop transpiration and water supply at
24 random spots in a rockwool
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Improvements reduction leaching

• Reduction heterogeneity water consumption
• equal crop growing conditions
• technical greenhouse constuction, temperature
  differences
• substrate

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Reduction heterogeneity irrigation

• water source
• devoid of organic matter
• perfect de-ironing
• flushing methane gas
• water treatment
• sand filtration
• chemical pre-treatment
• maintenance
• frequent high pressure
• flushing main pipes
• cleaning filters
• chemical cleaning between crops

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Reduction in N and P supply

• Reduction of NO3, increasing Cl
• Lower P supply

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Effect of NO3 Cl ratios,
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Developments soil-les systems

• 2 Closed systems
• Watercultures
• NFT
• DFT
• Substrate systems
• substrate in through/gutter
• substrate in foil, with drainage collection
  gutter
• Substrate on foil, drainage lines in foil
• Potting plants on tablet eb - flow system

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Principle of closed systems

• I input
• U uptake
• R root environment
• D drainage

I
U
Growing system
R
D
No losses
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Bottle necks

• Rapid spread of root / stem diseases
• fungal spores
• virus
• eelworms
• Rapid change in ionic concentrations
• salt accumulation
• macro nutrients accumulation, depletion,
  unbalanced ratios

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Important

• Nutrient input
• I Uopt
• Otherwise accumulation / depletion
• Na, Cl input
• Imax ? Umax
• Otherwise accumulation salinity problems

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• Input uptake
• I U
• I gt U accumulation
• I lt U depletion
• More specific
• Input lt uptake at max. acceptable
  concentration Rmax
• Imax ? Umax

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Waterquality

• Important parameters
• EC lt 1.5
• Na and Cl lt 1 mmol/l
• HCO3 lt 5 mmol/l )
• Fe-total lt 10 umol/l
• Ca, Mg, SO4, K, NH4, NO3 lt uptake capacity
  crop
• Mn, B, Zn, Cu lt limniting value (crop specific)
• ) acid neutralisation

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Na and Cl uptake
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Maximum acceptable Na (or Cl)and maximum uptake
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Na
I 1 mmol/l Na
U 1 mmol/l Na
Growing system 10 mmol/l Na
D ? gt 10 mmol/l Na
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EC, Na and Cl in recycling nutrient solution
Rainwater gone, change over to surface water with
gt 4 mmol/l Na
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If I gt Umax

• Discharging of nutrient solution necessary

I
U
Growing system
Discharge
R
D
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Uptake

• I input
• U uptake
• R root env.
• D drainage

I
U
Growing system
R
D
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Nutrient uptake

• Continuous proces
• Quantity growth dependent
• Concentration transpiration dependent
• Mutual nutrient ratios plant stage dependent

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• Uptake ? crop need

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Summary

• Large differences between elements
• Uptake strongly dependent of concentration at
  root
• Yield not affected in wide range
• Strong depletion (Nitrogen) possible

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Root environment

• I input
• U uptake
• R Root environment
• D drainage

I
U
Growing system root environment
R
D
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The input

• I Input / supply
• U uptake
• R root environment
• D drainage

I
U
Growing system
R
D
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Taking care of uptake ratios

• Basic composition tuned to uptake ratios of the
  crop
• Crop stage specific adjustments

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Important differences

• For closed systems, relatively
• higher monovalent ions (K, NO3-
• lower bivalent ions ( Ca2, SO4-)

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Mind !

• Effect of plant uptake affects compostion
  drainage water strongly
• In open systems, problems are leached out

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Nutrient management

• Right supply (nutrient solution)
• Adjustments to crop stage in time
• Regularly samplings and adjustments

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Why ?

• Governmental policy
• reduction of environmental polution
• Ground water (lt 60 mg NO3/l)
• Surface water (lt 2.2 mg N/l)
• North Sea Conference agreement (1985)

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Background
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Framework

• Closed systems for all substrate crops by nov.
  1999
• Re-use of drainage water obligatory
• few exceptions
• In case of calamity (disease)
• In case of exessive Na or Cl (plant specific)
• discharge to sewage system !

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Soilless culture

• Water quality
• Substrate
• Irrigation method
• Crop

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Soilless culture

• Restricted root volume
• 10 - 15 l m-2
• Small quantity solids
• Improved water quality
• rainwater / desalinized water

Poor availability of nutrients !
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Bottlenecks (water and nutrients)

• Water quality
• Nutrient supply

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I 1 mmol/l Na
U 1 mmol/l Na
Growing system 10 mmol/l Na
D ? gt 10 mmol/l Na
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EC, Na and Cl in recycling n.s. with tomato
Rainwater gone, change over to surface water with
gt 4 mmol/l Na
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If I gt Umax

• Discharging of nutrient solution necessary

I
U
Growing system
Discharge
R
D
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Uptake

• I input
• U uptake
• R root env.
• D drainage

I
U
Growing system
R
D
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Nutrient uptake

• Continuous proces
• Quantity growth dependent
• Concentration transpiration dependent
• Mutual nutrient ratios plant stage dependent

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• Uptake crop need

/
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Shift in uptake during growth
Trosontwikkeling
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Summary

• Large differences between elements
• Uptake strongly dependent of concentration at
  root
• Yield not affected in wide range
• Strong depletion (Nitrogen) possible

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Root environment

• I input
• U uptake
• R Root environment
• D drainage

I
U
Growing system root environment
R
D
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Potassium and quality
6
5
4

3
2
1
0
0,0
0,5
1,0
1,5
2,0
2,5
K/Ca ratio
Low Mg
moderate Mg
High Mg
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Taking care of uptake ratios

• Basic composition tuned to uptake ratios of the
  crop
• Crop stage specific adjustments

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Mind !

• Effect of plant uptake affects compostion
  drainage water strongly
• In open systems, problems are leached out

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Nutrient management

• Right supply (nutrient solution)
• Adjustments to crop stage in time
• Regularly samplings and adjustments

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To summarize

• Environmentally friendly
• No minerals to groundwater table and surface
  water
• Savings on water and nutriënts
• Requirments
• Proper water quality
• adequate nutrient supply and control
• Capital intensive
• growing system
• Drainage desinfection