Next Generation Growing INTRODUCTORY MEETING PLANT EMPOWERMENT Ing Mark van der Werf Tel : +31 (0)6 23 47 44 85 E-mail : gwn-consult@kpnmail.nl November 7th 2017
Timetable Introduction History Next Generation Growing Plant & Greenhouse balances Practise Summary en Evaluation
Introduction
Introduction Quikly write down: Name; Crop; Questions: What is the main reason why you are joining the NGG-group? What do you hope to learn today? Are there already cases available that we can discuss?
History of Next Generation Growing
2002/2004 First fully closed greenhouse 6
Back to the basics of physics Plaatjes 7
Plant balances 1. Assimilate balance 2. Energy balance 3. Water balance
Next Generation Growing Next generation Growing is a matter of knowledge and mind-set rather than technology and investments
2009: Kas als Energiebron starts NGG
2013: Study groups were formed
2015: NGG book
2017: Whitepapers by Hoogendoorn
Next Generation Growing = Plant Empowerment
Next Generation Growing
Plant in control!! Next generation Growing integrates Green fingers with physics & plant fysiology Plant is in control; Energy saving is not the goal, but a logic consequence.
(Dis)Advantages of NGG Advantage: Plant is starting point on each decision (3 balances); Every problem/issue/situation can be back related to the 3 balances; With every decision you have have to ask yourself: why do I do it this way and do I get the result I want? NGG forms a foundation for future investments (what is the added value). Disadvantage New ways of thinking (and acting) are against our green fingers and experience ; Especially in the beginning when things go wrong, people point at NGG.
How to listen to the plant needs?
Two engines work simultaneously PLANT/PHOTOSYNTHETIC ENGINE SOIL MICROBIOLOGY ENGINE Both need to function at their highest possible level of performance in order to grow healthy plants
It s all about photosynthesis
Highlights of NGG 1.Homogenous temperature 2.Improved Humidity control 3.Beware of Outgoing Long Wave Radiation 4.Keep an active climate 5.Use leeside and wind site vents 6.Maximize photosynthesis 7.Keep the right plant balance 21
Essence of NGG Assimilate balance Energy balance Water balance
It s all about balance Energy balance Energy balance Water balance Assimilates balance
Assimilate balance
Assimilate balance PRODUCTION: Source size: LAI Source process: Photosynthesis CONSUMPTION: Sink size: Plant load Sink process: Temperature Growth (shoots, leaves, roots & trusses); Production; Plant resilience. Temperature
Transport Transport through SIEVE TUBES: 1) Sugars (glucose) are loaded in the sieve tubes (Source); 2) Water follows by osmosis; 3) The inflow of water increases turgor pressure water starts moving; 4) Sugars are taken out of the sieve tubes (Sink). Transport kan beide kanten op zijn!! Sugars Starch
Ideal assimilate balance 1. Optimum production of sugars (maximum fotosynthesis); 2. Optimum distribution of produced sugars (no forming of starch in leaves); 3. Optimum ratio between sinks: Growing points (forming new chlorofyl); Roots (growth and supporting bio life root exudates); Fruits. PROCESSES ARE ALL CONTROLLED BY ENZYMES TEMPERATURE CONTROLLED 4. Feedback Sink and Source (next slide).
Interaction Sink-Source SOURCE = Fotosynthese LICHTINTENSITY CO2 / Humidity (VPD) High Sink gives positive signal to the Source + - PAR Light Temperature Lage Sink gives negative signal to the Source SINK = Growth/Roots/Fruit TEMPERATURE
Warm heads Cold fruits Low Sink signal; Storage of sugars (scarch) in leaves; Fotosynthesis slowing down (previous sheet); = 3 X LOWER PRODUCTION!! Quick growth at the top (more new trusses); Slow ripening. = HIGH FRUITLOAD!!
Optimize light/temperature ratio SUN 4 JUL WED 7 JUL TUE 6 JUL MON 5 JUL Too generative Balance FRI 9 JUL SAT 3 JUL THU 8 JUL Balance Too vegetative
Step 1: Monitor Ratio Temperature Radiation
Step 2: Control Ratio Temperature Radiation
How to support the assimilate balance Optimize photosynthesis Keep a steady ratio between temperature and radiation sum (RTR). This ratio is specific for each crop, variety, fruit load, season, etc.
Energy balance Plant (energy balance): Input: Radiation / artificial light; Heating pipes; Convection from warmer greenhouse air. Output: Evaporation; Longwave heat radiation; Convection to colder greenhouse air. Greenhouse (energy balance): Enthalpie (kj/kg): 1. Sensible heat; 2. Latent heat.
Energy balance - +
How to support the energy balance? Positive balance = growth Negative balance = risk & trouble Ensure sufficient air movement Protect the plant against heat emission
Water balance Plant (water balance): Water uptake; Water supply; Water drainage (evaporation, guttation). Greenhouse (water balance): Supply: evaporation of plants Drainage: ventilation Main objective is an increase of fresh weight and keeping the stomata open when growing light is available.
Water balance
Waterbalance Functions of evaporation: 1. Cooling (making the energy balance complete); 2. Transport of nutrient to and through the plant; 3. Uptake of some difficult nutrient (Ca en B). NGG and evaporation: 1. Energie balance is the foundation for evaporation! 2. Circumstances have great impact on the water balance (kind of evaporation, sunny/cloudy day, etc.).
Evaporation wet bolb evaporation Convection or wet bolb evaporation (energy supply through convection = air movement): Temperature difference between leaf (lower) and greenhouse air (higher); Humidity of the greenhouse air (lower dan 100%); Air movement.
Evaporation flute kettle evaporation Radiation- or flute kettle evaporation (energy supply through radiation):
VPD (Vapor Pressure Difference) Energy supply through radiation; Inside the plants water starts to evaporate; Water pressure builds up; Vapor pressure leaf > vapor pressure surroundings; Water vapor leaves the leaf through the stomata. De difference in vapor pressure between leaf and surrounding is VPD. VPD > 0 otherwise no evaporation 0,2 > VPD < 1,5 VPD > 1,5/2,0 water stress
Stomata and VPD Evaporation = VPD x SC (Stomata conduction) 12 = 2 x 6 (stomata open) better uptake CO2 12 = 6 x 2 (stomata closed) Stomata with low VPD Stomata with high VPD
Greenhouse water balance
Climate control based on Psychrometric chart
Absolute humidity Absolute humidity to control Balance: Evaporation = drainage Radiation Time
How to support the water balance Irrigate to the plants needs Align irrigation to evaporation Provide high humidity RH under high radiation Monitor and avoid plant stress
Summary: How to grow productive, strong and resilient crops? Optimize photosynthesis Ensure sufficient activity for nutrient uptake Protect the plant against excessive conditions Support the plant in maintaining its balances That s Growing by Plant Empowerment!
Practical applications
NGG in practise 7 growing tips 1. Homogenous temperature 2. Improved Humidity control 3. Beware of Outgoing Long Wave Radiation 4. Keep an active climate 5. Use leeside and wind site vents 6. Maximize photosynthesis 7. Keep the right plant balance
Tip 1: More equal temperature Insulated walls Well designed heating system Ridge partitioning / APEX seals Double screens No screen gaps
Tip 1: More equal temperature Screening without moisture gaps Ventilation above a closed screen (instead of minimum pipes)
Tip 2: Improve humidity control 1. Stomata must stay open for optimum fotosynthesis; 2. Prevent plantstress by monitoring VPD; 3. Air movement for continuous evaporation;
Tip 2: Improve humidity control
Tip 2: Improve humidity control Screening at night and humidity control: Action 1: Start venting (lee and wind side); Action 2: Create chimney with gap in screen (for extra drainage of humidity); Action 3: Additional heating with minimum pipe.
Tip 2: Improve humidity control (summerized) Improved Humidity control Keep an eye on Absolute Humidity (AH) Keep screens closed Ventilate above closed screen Use (vertical) fans rather than minimum tube Avoid unnecessary evaporation Fix leaks in drain systems, etc
Tip 3: Beware of Outgoing Long Wave Radiation
Tip 3: Beware of Outgoing Long Wave Radiation Sunny day in autumn Solari Pyrgeo Break even Break even Sunrise Sunset
Close screen earlier but keep an opening to balance temperature and humidity towards night Outside 10 C Greenhouse T > heating setpoint Greenhouse T = heating setpoint
Tip 3: Beware of Outgoing Long Wave Radiation
Tip 3: Beware of Outgoing Long Wave Radiation
Tip 4: Keep an active climate
Tip 2: Keep an active climate Calcium uptake Root activity and plant turgor / guttation Stimulate evaporation by air movement rather than heating / minimum tube Screen control
Tip 5: Using windside much quicker
Tip 5: Using windside much quicker Use leeside and wind site vents Above closed screens But also with open screens Better temperature and humidity control with smaller vent openings
Tip 6: Maximize fotosynthesis Less ventilation -> + RV, +CO2, + Temp Avoid water stress (a too high VPD) Use misting rather than shading Monitor VPD
Example plant temperature & VPD Tomato
Example plant temperature & VPD Phaleanopsis
Tip 7: Keep the right plant balance TUE 6 JUL SUN 4 JUL Generative Balance FRI 9 JUL WED 7 JUL SAT 3 JUL THU 8 JUL MON 5 JUL Balance Vegetative
Tip 7: Keep the right plant balance WED 7 JUL TUE 6 JUL SUN 4 JUL TUE 6 JUL SUN 4 JUL FRI 9 JUL SAT 3 JUL THU 8 JUL MON 5 JUL FRI 9 JUL WED 7 JUL SAT 3 JUL THU 8 JUL MON 5 JUL Without light/temp. optimization With light/temp. optimization
Tip 7: Keep the right plant balance Proactive control vs correction Long term light / temp integration is good Daily balance light / temp is better
Summary and Discussion
Overal summary Plant empowerment: The Plant performs at best when in balance Focus on Optimizing the driving factors of Photosynthesis Water & Energy balance can be improved by irrigation based on evaporation energy Assimilate Balance can be improved by controlling Temperature Light Ratio
Evaluation next step Tips 1 7: 1. Homogenous temperature; 2. Improved Humidity control; 3. Beware of Outgoing Long Wave Radiation; 4. Keep an active climate; 5. Use leeside and wind site vents; 6. Maximize photosynthesis; 7. Keep the right plant balance. Monitoring climate by Lets Grow.com