sustainable greenhouse production - growsave · blew line: hd under sls 10 up + fixed ac foil (*)...

Sustainable Greenhouse Production Saving Energy & Managing Water

Chairman

Paul Howlett Head of Agronomy

WIGHT SALADS GROUP

What is Sustainable Greenhouse

Cultivation? Stuart Lambie, Sustainability Manager, GRODAN

Sustainable Greenhouse Production - Saving Energy & Managing Water.

Stoneleigh, January 29th 2014

What is Sustainable Greenhouse Cultivation?

• Measuring sustainability performance & identifying the key

sustainability “hotspots” in greenhouse cultivation

• Sustainability measurement in practice - the development

of sustainability measurement tools by The Sustainability

Consortium

Sustainability

Sustainability: Meeting the needs of the present without compromising

the ability of future generations to meet their own needs.

Protecting the environment, economic growth and social

development must be balanced.

Sustainable growing practices in greenhouse

horticulture will lead to economic benefits for your

business.

Definition adopted at the UN Conference on Environment and Development , Rio de Janeiro, 1992

Life Cycle Analysis (LCA):

The "Compilation and evaluation of the inputs, outputs and the

potential environmental impacts of a product system throughout

its life cycle" (ISO 14040, 1997).

LCA examines environmental aspects such as:

• Energy consumption

• Use of other raw materials

• Emission of hazardous substances

• Contamination of ground water, rivers and seas

• Use of agricultural land

Expressed as a score. The higher the score, the greater the impact on

the environment. Apart from the overall score, an LCA reveals the

“hotspots” which can be focus areas for improvement.

Measuring sustainability performance

using life cycle analysis (LCA)

End point score for greenhouse

tomatoes in The Netherlands

End point score for greenhouse

tomatoes in The Netherlands

Share of the environmental impact of growing medium in year-

round cultivation of greenhouse tomatoes is less than 1%

Impact sources within each LCA impact category

Distribution of LCA impacts for a tomato crop in The Netherlands, 2011

Reducing energy input

LCA end point score

LCA end point score

-27%

LCA end point score

-40%


• Measuring sustainability performance & identifying the key

sustainability “hotspots” in greenhouse cultivation

• Sustainability measurement in practice - the development

of sustainability measurement tools by The Sustainability

Consortium

Who are The Sustainability Consortium?

What do The Sustainability Consortium do?

• informing decision makers on product sustainability across

the entire product lifecycle.

• creating sustainability-related knowledge about particular

product categories.

• continuously adding to the scope of products covered by

the Sustainability Measurement and Reporting System

(SMRS).

Mission

“Through multi-stakeholder collaboration, our mission is to design and

implement credible, transparent and scalable science-based measurement

and reporting systems accessible for all producers, retailers,

and users of consumer products”.

SMRS: Measuring the sustainability impact of a category

5. On-farm energy

efficient

management

practices and

technologies:

Reduce energy use

associated with

agricultural production

through methods

such as improved crop

varieties, improved

cropping techniques,

energy efficient

technologies, or

reduced transportation

on-farm.

Category Sustainability Profile: Tomatoes


12. Implement

practices for

greenhouse energy

efficiency: Adopt

practices and

technologies that

reduce energy use

by greenhouses.

This may include

energy efficiency

technologies and

efficient HVAC

systems as well as

favouring the use of

renewable energy.

7. Practices and

technologies that

reduce fertilizer run-

off: Adopt practices

and technologies

that reduce fertilizer

run-off. This may

include fertilizer use

efficiency, precision

fertilizer application

practices, or

irrigation

techniques.



13. Implement

programs, practices,

and technologies to

optimize irrigation

water use: increased

water use efficiency,

improved irrigation

technology,

precision irrigation,

water re-use and

recycling.

Case example: using TSC tools

In conclusion…………

• Greenhouse cultivation which fully addresses “On-farm” energy use

as the sector’s biggest single sustainability “hotspot”

• Greenhouse cultivation which makes measurably more efficient use

of fertilisers and water to improve sustainability performance

• Greenhouse cultivation which addresses the sustainability concerns

of global food retailers:

– using academically developed measurement tools

– by addressing “hotspots” and “improvement opportunities”


Sustainable Greenhouse

Production

Saving Energy and Managing Water

Birmingham, 29th of January 2014

Aat Dijkshoorn

Programma Kas als Energiebron greenhouse as source of energy

Voor een krachtige klimaatneutrale glastuinbouw

What can you expect?

• Introduction KaE

• History of HNT- The New Way of Greenhouse Cultivation

• Knowledge transfer and interaction growers

• What’s next in HNT?

Why a progam like KaE?

Founders of KaE

Ambitions towards 2020

• New greenhouses 2020 climate neutral

• Energy use in existing Greenhouses reduced by 50% cf 2010

Multiple strategies and solutions

Energy saving Sustainable energy Efficient Fossil CO2

Heat demand Light Solar energy Geothermal Biofuels

(bio CHP)

CHP Sustainable CO2

nutrition

Trias Energetics

Approach

R&D

Demonstration projects

Communication

Monitoring

& Evaluation

exploration

Solving problems

Results ultimo 2013

• Energy efficiency doubled cf 1990

• Geothermal Energy: 10 sites realised

• > 200 ha (semi-) closed greenhouses

• HNT: 5-10 m3/m2 savings

• Diffuse glass

• Starting new innovations:

– “Daylight Greenhouse, climateneutral

– VenlowEnergy Greenhouse (60% reduction heat demand)

– New dehumidifying options

– (Hybrid) LED options

(Semi) closed greenhouses

• Summer cooling

• Less ventilation

• CO2 + fotosynthesis higher

• Use of storage in aquifer and

heating pump

Conclusions:

• Over taken by CHP

• Only economic when cooling is

needed

• Economics depend on prices

gas/elec

Het Nieuwe Telen

HNT step 1

Nivolator: 4500 m3/hr

at 250 m2

V-FloFan: 5050 m3/hr

at 350 m2

vertifan: 3500 m3/hr

at 450 m2

Vertical air movement

Verticale luchtbeweging

Alternative ATE’s

Easy to fit in existing greenhouses

Activities on HNT 2009-2013

• Demonstrations at GreenQ IC on 1.000 m2

• Monitoring on commercial scale

• Supporting development of technologies

• Growing concepts for more crops

• Subsidies on ATE’s + 2nd screens

Application of ATE and 2nd screen

New approach 2014

HNT – 0: More emphasis on energy saving in

common nurseries using the knowledge of

HNT

HNT – 1: ATE’s and 2nd screens

HNT – 2: more isolation, less respiration

=> climate neutral

Definition HNT:

combination of knowledge from physics

and plants for optimal growth with

minimum of energy

Activities on knowledge transfer

• All results and backgrounds on website

• Research reviewed by growers committees

• Trade press

• Seminars and events

New:

• Small regional gatherings

• Study groups on HNT

– Combining theory + practice

– Using Let’s grow

HNT climate simulation tool

hnt.letsgrow.com/Hnt

http://hnt.letsgrow.com/Hnt



New research on HNT

Control of Humidity • lowering night + early morning evaporation

• effects compensation higher EC

• more equality in greenhouse climate

More isolation • double glass + AR coating

• new materials on screening: less heat emittence night, more light transmittance day

Use of latent heat • Heat pump

• Hygroscopic dehumidification

• Other alternatives

Emphasis on knowledge transfer

Large savings for some (new to built) greenhouses

Small savings for everyone add up to more results:

• More study groups to come

• Helpdesk on HNT

• More E-learning

• Continious monitoring

Thank You for your attention

www.energiek2020.nu

Aat Dijkshoorn

(+31) 681 613 617

[email protected]

http://www.energiek2020.nu/

http://www.kasalsenergiebron.nl/

Coffee Break

Please be back to your seat at 11.25

Double energy screens optimal climate and high energy savings

Paul Arkesteijn

29-01-2014

1. Energy saving screen-types

2. Which screens to choose?

3. How to screen?

4. Climate under double screens

5. How much energy can be saved?

Agenda

1. Energy saving screen-types

Type

Direct light

(blew sky)

Diffuse light

(clouds)

Energy saving

XLS 10 REVOLUX 87% 80% 47%

XLS 10 ULTRA REVOLUX 85% 76% 47%

SLS 10 ULTRA PLUS 88% 81% 43%

- Double screen: energy saving is 63%

- H2no upgrade

XLS 10 ULTRA REVOLUX, diffuse

XLS 10 REVOLUX, clear as glass

Relative humidity

Humid, produced by the

plants, is transported

through the Svensson

screen.

Humid transport screen is of importance

Standard screens

Condense

droplet

screen

yarn

Condense water more easily reach the yarn

Screen is more dry More light passes through

H2no results in high light transmission,

also when the screen is condensed

H2no in practice

SLS10UP H2no SLS10UP

Photo’s are made in the morning, both screens were condensated

2. Which screen to choose?

Diffusity is an advantage in summer when a bit of light shading is needed. Example: Paprika, cucumber, strawberry, flowers and plants XLS 10 ULTRA REVOLUX

In case of no shading in summer Example: Tomatoes XLS 10 REVOLUX 4% extra Light

In case of double screen 2x XLS 10 REVOLUX XLS 10 REVOLUX + XLS 10 ULTRA REVOLUX

Option1:

XLS10 REVOLUX + XLS17 REVOLUX

Option2:

XLS10 REVOLUX + XLS 10 REVOLUX

Screens and “New way of Growing”

Energiesaving:

70% 47%

Energiesaving:

63% 63% en 47%

0

20

40

60

80

100

120

0:00 2:00 04:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00

Axis

Tit

le

Radiation in januar and screen closure

radiation

0

20

40

60

80

100

120

0:00 2:00 04:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00

Radiation in januar and screen closure

radiation

Screen 1, transparent

0

20

40

60

80

100

120

0:00 2:00 04:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00

Radiation in January and screen closure

radiation


screen 2, alu

0

20

40

60

80

100

120

0:00 2:00 04:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00

Sun radiation in January in Holland and screen usage

radiation


screen 2, alu


3. How to screen?

Winter:

• Open and closing of the energy screen?

• Screen gap for RH, HD?

Double screen:

• Which screen to open first?

Summer:

• Close at what radiation level?

• Screen gap

www.svenssonglobal.com

4. Climate under double screens

Blue line: RH under single screen (*) The New Growing

Yellow line: RH under double screen

Tomato, Relative Humidity under single and double screen (*) in closed position

0

1

2

3

4

5

6

7

8

VD afd 3

Blew line: HD under SLS 10 UP + fixed AC foil (*)

Yellow line: HD under XLS 10 REVOLUX + SLS10UP

Paprika, Humidity Deficit under single (*) and double screen in closed position

Screen hours in practice

0

500

1000

1500

2000

2500

3000

3500

4000

tomato XLS10REV tomato doubleHNT

paprika double paprika AC foil cucumber cucumber AC foil

screen hours

screen hours double

sceen hours day

5. New Svensson-app shows the savings of the screen

Energy saving report

How much energy can be saved?

tomato paprika cucumber

XLS 10 REVOLUX 10,9 m3 14,2 m3 14,2 m3

2 x XLS 10 REVOLUX 15,6 m3 19,9 m3 19,9 m3

New way of growing

22,3 m3

24,1 m3

24,1 m3

Questions?

[email protected]

Peter Geelen Plantmonitoring.NL

81

More growth with less energy ?


Tel : 06 – 33 852 838

E-mail : [email protected]

2014 UK Energy Event 29 january 2014

1 : More growth with less energy ?


82

A :

you never can

reach the best

production and

quality with a

minimum use of

gas

B :

it is absolutely

possible to reach

a higher yield

with less gas

2 : saving of energy


83

A :

the best way to

save energy is to

rase temperature

during the day

together and

decrease the

night temperature

B :

energy saving is

easier when you

can afford a

higher night

temperature

3 : saving of energy


84

A :

energy saving

is easier in

week 1 t/m 15

B :

energy saving

is easier in

week 15 t/m 30

4 : releasing humidity


85

A :

releasing

humidity is easier

with a closed

energy screen

B

you always

release humidity

better with an

open energy

screen

Peter Geelen Plantmonitoring.NL 86

10 gr / kg

20 °C

70 %

15 °C

95 %

Is export of

humidity

decreased ?

Absolute

Humidity

http://www.google.nl/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&docid=Bp21SU15iQx2oM&tbnid=AnShOy-301ZerM:&ved=0CAUQjRw&url=http://nl.wikipedia.org/wiki/Necker-kubus&ei=WW2xUpHcMsec0QW28IAI&bvm=bv.58187178,d.d2k&psig=AFQjCNHhe86tQFjNt8OptXknV_0dtr5clA&ust=1387445972752582


Humidity balance


87

Humidity balance of a greenhouse

is best monitored by

AH : Absolute Humidity - gr / kg

Humidity balance


88

evaporation

condensation

ventilation



AH on your climate computer


89

Balance : evaporation = export

AC foil + energy screen


90

RH and VD


91

Effect of Temperature


92

Background : humidity control and screening


93

20 °C 20 °C

20 °C 12 °C

10 °C

Export of humidity


94

By condensation

Temperature difference between

air temperature under the screen and glass temperature

By ventilation

Difference of AH in the glasshouse and outside the glasshouse

Screening in Summer


95

Results


96

2012 2013 incl. CO2 production

screening hours 3425 4211 +786 hours + 23 %

gas m3 / m2 33,9 31,6 -2,3 m3 - 7 %

Extra monitoring tools


97

Outside

Measuring humidity ( AH ) outside

Measuring emission of radiation with pyrgeo - meter

Above the screen

Measuring humidity ( AH ) + temperature above the screen

Under the screen

Measuring humidity + temperature at 3 levels in the crop

Experience in Holland


98

2013 : 10 – 15 growers

2014 : training for 100 growers

training for consultants

Peter Geelen Plantmonitoring.NL 99

thank you

for your

attention

Lunch

Afternoon

presentations start at 13.15

Precision Irrigation Doing more with less in a better way

Sustainable Greenhouse Production - Saving Energy &

Managing Water. Stoneleigh, January 29th 2014

Greenhouse growing today

Climate

Root zone

Genetics 27m3 gas

The basic rules for irrigation

• Every irrigation results in a

vegetative plant reaction!

• Mistakes i.r.t a lower energy input

are made on the dark mild

(vegetative) days.

• Do not chase substrate EC.

• Drain should not be your “goal” but

the result of a structured irrigation

strategy.

• Control EC with a strong well

balanced crop & structured irrigation

strategy.

More

“Veg”

More

“Gen”

Range

Ec slab ↓ ↑ 2,5-8,0mS

Ec drip ↓ ↑ 2,0-4,0mS

1WC slab ↑ ↓ 45-80%

∆WC ↓ ↑ 6-15%

Start Earlier Later 0 / +3 hrs

SR

Stop Later Earlier 0 / -5 hrs

SS

1Dependant on substrate choice.

General steering parameters in the root zone

More “advanced, generative &

compact young plants are demanded

by growers

Delaying the moment of irrigation

for as long as possible results in

generative development Vegetative Generative

Max block

weight (g)

1560g 2840g

1560g 2840g

Min block

weight (g)

1360-390g 2540-585g

1250-280g 2375-420g

Minimum

WC%

65-70% 45-50%

Time between

irrigation

Shorter Longer

Ec irrigation

water

2,0-2,8mS 3,5-5,0mS

110 x 10 cm Plantop Delta block 210 x 15 cm Plantop Delta block

More “generative” nutrient schemes

are used

NO3 SO4 P Cl NH4 K Ca Mg Fe Mn Zn B Cu

17,2 5,0 1,0 0,0 0,0 6,1 7,4 3,66 16,1 10,7 5,38 43,0 0,01

Example: Target mMol-1 & µMol-1 tomato at EC 2,8mS


17,2 5,0 1,0 0,0 0,0 6,1 7,4 3,66 16,1 10,7 5,38 43,0 0,01

-8,0


17,2 5,0 1,0 0,0 0,0 6,1 7,4 3,66 16,1 10,7 5,38 43,0 0,01

-8,0 2,0 4,0

Start of the cultivation cycle

pre-planting phase or plant

directly to the slab?

Your goal is exactly the same

• Controlled generative plant development &

good quality cluster development.

– Heads visible & higher than the rest of

the plant.

– Tight curling leaves already at midday.

– Dark green coloured leaves.

– Continued uniform growth of the

shoots & LAI.

• General rule-of-thumb:

– 1st cluster flowering <15/1 pre-planting

– 1st cluster >15/1 direct to slab.

Pre-planting phase

• How long beside the plant

hole?

• “Norm” for slab contact when

2nd cluster is starting to flower.

• Length of pre-planting period

depends on block size & type.

– keep control of the irrigation

– increasingly 10 x 15 cm blocks

– make slab contact when you give

450-550ml/block/24hrs.

Part-draining the slab & planting

directly

Control of substrate WC.

Slab EC 4,0 - 5,0 mS.

Even gutter profile.

Well rooted block.

Generative plant material.

Good interaction WC over height of block / slab

Irrigation strategy– Phase 1 & 2 Maximum vegetative effect irrigate after midday

Maximum generative effect irrigate at night

Acceptance of lower humidity deficits highest humidity at night & lowest (plant) temperature in

pre-night

Precision irrigation creating resilient plants as well as steering plant

balance & cluster quality

Survey (WUR) of 100 Dutch tomato growers

found a strong link between water applied in

first 8 weeks of the cultivation and subsequent

incidence of Botrytis infection.

During rooting through the

substrate set yourself goals for

steering WC & EC

Precision irrigation when thinking what is an acceptable EC?

Radiation

(W/m2)

EC substrate

Tomato

EC substrate

Cucumber

EC substrate

Pepper

200 8,0 5,0 6,0

400 6,0 4,0 5,0

600 5,0 3,5 4,0

800 4,0 3,2 3,5

1000 3,5 2,8 3,0

Appreciate the difference between

drain EC and substrate EC

Drain hole configuration & EC

control

Irrigated volume

The quality and position of the drain

hole will affect the functionality (WC

& EC) of the substrate.

Precision irrigation drain is not the goal but should be a result of a

structured irrigation strategy

Max radiation

W/m2

Radiation sum

J/cm2

Traditional

drain %

Precision

Growing drain %

200 500

20-30% 400 1000

600 1500

30-60%

800 2000

1000 2500

Max radiation

W/m2

Radiation sum

J/cm2

Traditional

drain %

Precision

Growing drain %

200 500

20-30%

5%

400 1000 10%

600 1500

30-60%

15%

800 2000 20%

1000 2500 25%

Nutrient balance

• As the fruit load increases in

Phase 3 (week 12 – 18) & you

work with:

– low volumes of applied

irrigation.

– low drain volumes

– combined with recycling

nutrient solution

• In line with emission

reduction!

• BE AWARE OF THE NUTRIENT

BALANCE IN THE ROOT ZONE

Structured irrigation strategy leads to

a stable root zone environment

Low stable WC and high stable

EC: Phase 2/3 (Generative)

High stable WC and low stable

EC: Phase 4/5 (Vegetative)

EC EC WC WC

Summary

• Irrigation results in a vegetative plant reaction

– in line with energy management steer as “generative” at the start of

the crop.

• Generative steering within the root zone starts in propagation

– do not view propagation and production as two separate cultivations.

• Whatever your planting date your goal is to continue controlled uniform

generative plant development.

– set targets for WC & EC

– monitor & keep control.

• Be critical on dark days, accept higher EC levels in the substrate and

above all do not over supply water by chasing substrate EC.

© DLV Plant

Effcient use of energy in a tomato crop

• History – “Low” energy price.

– Early production at high price level.

– Ungrafted plants.

• Planning crop – Planting date => end of the crop

– Options of insolation

– Planting material

– Energy available => planning input energy

– How to do it?

© DLV Plant

Planning of the crop

• Early planting date – Fruitload in January => low 24 H-Temp needed

– RH difficult steering with low Temperature

– Productspecifications and demand from market.

– Cropchange in November

• Later planting date – High 24 T demand at start of the crop => insolation usefull

– Growing with increasing light level

– Keep the crop healthy to the end => energy uptake.

– Cropchange in late December.

© DLV Plant

Planting material => saves energy

62 days plant. Grafted and

pinched at second leave.

First flower at 68 days.

© DLV Plant

Planting material => energy intensive

Grafted single head.

Needs 2 weeks in house to

first flower.

First truss at leave nr. 12

© DLV Plant

Planning energy consumption

• Energy savings options – Movable screen

– Combination AC foil

• Speed of the crop. – Result of energy input ( fixed max pipe ) and insolation of

the glasshouse and outside temperature.

– The growers is restricted.

• Planning energy – Become conscious of the possible options

– Planning 2014

• Normal glasshouse; one screen.

-

0,20

0,40

0,60

0,80

1,00

1,20

1,40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

-

5,00

10,00

15,00

20,00

25,00

30,00

35,00

Weekly

consumption

Cumulative 2014

24 H Temp

© DLV Plant

Climate control

• Temporarily accept a less optimum situation

=> focus on long term.

• Pre-night aggressive => root pressure to

wounds of leaf cutting?

• Steady appraoch is energy friendly.

© DLV Plant

heating setpoint

10,0

15,0

20,0

25,0

30,0

0 1 2 2 3 4 5 5 6 7 8 8 9 10 11 11 12 13 14 14 15 16 17 17 18 19 20 20 21 22 23 23 24

time

tem

pe

ratu

re

Work on balance

Appearance of the crop

Day length => 24 hr T

nor

mal

light

increase

A 24h 17,4 18,4

A N 15,9 16,3

A D 19,4 21,5

© DLV Plant

24 Temperature versus Light

• Basic need of the crop 100 Js/cm

• Fruitload 100 Js/cm a full set truss

• Basic 24 T => Beef 17,5 C

=> Classic 17 C

• Light increase => 300 Js/cm for 1 C

• Example => 600 Js lightlevel

3 trusses => 300 Js

Crop => 100 Js

Left over => 200 Js => 17 + 0,6

Correction to stem distance and light transmission

glasshouse

© DLV Plant

Improve energy efficiency

• Equal temperatures in the house; horizontal and vertical.

– Improve knowledge => use measuring equipment

– Air movement needed

• by pipe?

• force ventilation

• Crop type – Higher dry matter => “hard crop type”

– how:

• CO2

• EC and adjustment to fertilisation

– Open crop type LAI under control

• Expose 2 leaves a truss

• Variety choice

• De-leafing strategy

© DLV Plant

New view on set point min pipe

• Only use min pipe when needed – Keeping constant 30 or 35oC during day and night => energy slips away!

• Example – Basic pipe is air temp => so no pipe needed => set point 0oC

– At RH from 87% til 90% + 50oC

– So 87% => no min pipe

– 90% => 50oC min pipe

• I.C.W. min vent

– Calculated pipe < 40oC => min vent 1-3%

– Calculated pipe > 42oC => min vent 0%

– Creates an “open climate”

© DLV Plant

Suitable applications

• Accept humidity deficit < 2.0 gm3

– In day one also < 1.0 gm3 measured

– Correct in day two

• Grow a powerful crop => in balance

• Sensitivity Botrytis – Crop with dry matter content ( so dark green appearance)

– EC drip adjust to cooling and growth

• Weather conditions change to cool => increase EC drip

• Extra attention for hygiene and performance of crop

work – When raining no leaf cutting or truss scratching

© DLV Plant

Results from 2001

• Change of variety.

• Use of grafted plants.

• Change of the planting date.

• Change of planting material.

• EC level from 3 to 5 in the slab.

• Min drip 2,8 EC; at the start 4 EC.

• Focus on energy; daily measuring uptake.

• High performance of the cropwork.

• IN 10 years + 12 kg and minus 15 m3 gas.

© DLV Plant

Yield (Kg/m2) and energy input (m3 gas) for a Dutch tomato

greenhouse with standard boiler & pipe rail system

Pulling it Together

Chris Plackett

Farm Energy Centre

• How much of today’s information are you already applying?

• How much could you apply?

• What’s stopping you using it?

Some questions?

• CO2

– How much do you need?

– Can you get it from gas?

– Alternative sources?

– How & when should you use it?

Other Technical Areas?

• What work is needed

– HDC?

– GrowSave?

– Collaboration with Groups in Holland?

– Other providers?

R&D or Technology Transfer

sustainable greenhouse production - growsave · blew line: hd under sls 10 up + fixed ac foil (*)...

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