Development of Mathematical Models for Use in Management of Irrigation, Fertilization and Run-off from Ornamental Greenhouse Production.

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Development of Mathematical Models for Use in
Management of Irrigation, Fertilization and
Run-off from Ornamental Greenhouse Production.

• Prof. Heiner Lieth
• Environmental Horticulture, University of
  California, Davis

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Approach

• Models can package quantitative scientific
  information
• to make calculation (optimization)
• to gain understanding
• direct use in managing greenhouse crop
  production systems
• Project will result in a model to simulate the
  growth and development of a greenhouse crop in
  relation to root zone variables
• moisture content
• concentrations of various ions
• dissolved oxygen concentration
• Model system
• Greenhouse cut-flower rose (the most extensively
  produced greenhouse cut-flower crop).

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Collaborators on Rose modeling research

• Scientists from elsewhere
• Michael Raviv, Moshe Silberbush, Israel Enrique
  Eymar, Spain Hak Ki Shin, Wan Soon Kim, S.
  Korea Pushpendra Chauhan, India
• Post doctoral researchers
• LinYing Li, Loren Oki
• Graduate students
• Soo Hyung Kim, Loren Oki, Ling Sun, Melody Meyer,
  Carola Gonzalez-Kessler, Robby Flannery, Neil
  Mattson
• Undergraduate students
• Jennifer Griset, Julie Hooper, Kimberly Layne,
  Jackie Bergquist, Nancy Sweet, and others
• High school students
• Pam Ng, Stella Chun, Hattie Brown, Rochelle Lee
  and others

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Rose shoot/crop model

• Objective of the research project
• develop a model to help us better understand rose
  crop physiology and crop productivity
• simulate rose crop growth and development in
  relation to the variables that determine
  production
• Particular focus root-zone variables.

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Our rose modeling project

• Strategy Modular approach start at the
  physiological level and work up to crop systems
  level

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Our rose modeling project

• Strategy Modular approach start at the
  physiological level and work up to crop systems
  level

• The approach deal with various submodels for the
  processes/physiological mechanisms
• Model for rose leaf photosynthesis
• Model for dry matter partitioning
• Model for shoot growth
• Model for rose shoot development

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Model for rose shoot development

• occurrence of sequence of events over time
• e.g. leaf unfolding and flowering stages

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Model for rose shoot development

• Code Event
• CT Cutting/pinching (harvesting) leading to the
  breaking of the bud
• BB Bud Break (break10 mm long)
• Ln Unfolding of leaf number n (n1,2,3...)
• VB Flower bud is first visible to the naked eye
  (Visible Bud)
• LL Unfolding of the Last Leaf
• HV Shoot becomes harvestable (reflexed sepals,
  petals unfurling)

Basically we track how long a shoot spends in
each phase. (e.g. phase from VB to HV is denoted
as VBHB)
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Modeling crop development

• Temperature drives shoot development
• Thermal units or heat units can be used to
  represent the plants sense of time
• Thermal units Sum of all degrees of
  temperature above some base temperature

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Graphical view of model

• Provides a time-table for when each event occurs

Accumulated thermal units (integral of T-Tb)
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Phases of Rose Development

• Cultivar CTBB BBL1 L1VB VBLL LLHV
• 'Cara Mia' 209 95 165 83 202
• 'Royalty 201 77 174 66 263
• 'Sonia' 194 93 160 85 172
• units C day

Implication we can fine-tune the timing of
holiday crops
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Rose Shoot model

• Carbon budget model
• main compartments Lleaf, Sstem,
  Freproductive, Clabile carbon pool, Bbase
• input variables IIrradiance, Ttemperature,
  CO2CO2 concentration
• rates Tup, Tdown CHO import/export rate,
  PSYNphotosynthesis rate, RG, RM growth and
  maint. respiration rate
• shoot (canopy) architecture iinternode number,
  Lileaf i, Iilight, ...

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Rose Crop Simulation model

• Population of flowering rose shoots proposed
• various shoot ages (bud break dates)
• various positions in the canopy (vertically)
• shoot model is then used for each class of shoots
  to form crop model

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Prior to Floriculture Initiative funding

• Workshop sponsored by Roses Incorporated focused
  on needed research related to modeling effort and
  benefits to growers
• Resulted in the following grower recommendations
  for where to focus in the modeling research

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Rose Crop Simulation model
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Rose Crop Simulation model
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Rose Crop Simulation model
lamp light
CO2
Day Temp
Night Temp
The rose grower funding was known to be
inadequate to accomplish all this research.
The rose grower funding was known to be
inadequate to accomplish all this research. At
start of Initiative funding we had a
grower-guided project which could be used as a
basis for research into issues related to
irrigation and fertilization, such as run-off and
TMDL.
productivity
flower head size
foliage quality
?
RFR
potential flower head size
soil water potential
NO3
NH4
K
PO4
Micros
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Focus of Initiative-funded research

• Focus on model development specifically for
• Cut-flower rose production, especially
  hydroponics
• Nutrient uptake and nutrient content of effluent

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Why we need this research

• Hydroponic rose production
• Roses grow in containers
• In coconut coir or some other substrate
• Plastic containers may have drainage holes or
  special reservoir with overflow

• Automated drip system irrigation
• Numerous irrigations per day
• Drainage is channeled into reservoir for
  recirculation or to be discarded.

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Focus of Initiative-funded research

• Focus on model development specifically for
• Cut-flower rose production, especially
  hydroponics
• Nutrient uptake and nutrient content of effluent

Why we need this research

• So we need to know how much of each nutrient the
  roses have removed from the irrigation solution
  to be able to
• Reuse it (optimizing it)
• Minimize environmental impacts

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Focus of Initiative-funded research

• Focus on model development specifically for
• Cut-flower rose production, especially
  hydroponics
• Nutrient uptake and nutrient content of effluent
• Goal
• Develop tools based on models, that growers can
  use in production management
• Help growers reduce fertilizer in waste water
  (run-off)
• Optimization of fertigation program by
  calculating what plants have removed from
  solution.
• Leverage funds to attract additional resources to
  multiply funding to get additional research done!

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Remainder of presentation

• Highlight three of the areas of the project
• Example of developing grower tool
• Development of grower tool for rose production
  timing
• Example of research to improve our understanding
• Oxygen in the root zone
• Example of simulation model of nutrients in rose
  production
• Simulation of N and K in rose crop production

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Development of grower tool for rose production
timing

• Based on model for rose shoot development
  (presented earlier in the talk)
• Prediction of occurrence of sequence of
  events/stages such as leaf unfolding and flower
  development stages

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Observable stages of development
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Phases of Rose Development

• Cultivar CTBB BBL1 L1VB VBLL LLHV
• 'Cara Mia' 209 95 165 83 202
• 'Royalty' 201 77 174 66 263
• 'Sonia' 194 93 160 85 172
• units C day

Implication this can be used in timing rose
crops for holidays Software was developed to
help growers make use of this model
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Software to make use of this information

• Used as follows (1) load program

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Click on File and load parameter data
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Select the variety of rose
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Enter the greenhouse conditions (average day and
night temperature,)
Select the stage that is fixed and put in the
date corresponding to it.
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Example Valentines Day calculation

• Select a target harvest date for the Valentines
  day cut

• Put in expected temperatures in greenhouse
• Calculation shows the previous cut or pinch needs
  to occur on 12/22/2002, Bud break will occur
  12/30 and Visible Bud will be on 1/16/03.

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Remainder of presentation

• Highlight three of the areas of the project
• Example of developing grower tool
• Development of grower tool for rose production
  timing
• Example of research to improve our understanding
• Oxygen in the root zone
• Example of simulation model of nutrients in rose
  production
• Simulation of N and K in rose crop production

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Dissolved Oxygen Concentration in the
Rootzone(Research Assistant Robby Flannery)

• Background
• Roots need oxygen to stay alive and to be able to
  
• absorb nutrients
• absorb water
• Roots need oxygen to obtain energy from
  carbohydrates generated through leaf
  photosynthesis
• In our research we saw signs of oxygen
  deficiency, despite well-aerated medium

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Dissolved Oxygen Concentration in the Rootzone

• Recently we found new instrumentation to measure
  dissolved oxygen concentration in small samples
  and in-situ.

• Allows measurement directly in the rootzone or in
  liquids
• Instantaneous
• Non-invasive non-consuming

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Dissolved Oxygen Concentration in the Rootzone

• Measurement of O2 in media in roses in hydroponic
  buckets

Fiber-optic line on O2 sensor probe
Temperature probe
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Root zone conditions (with plant)
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Focus on a number of root-zone variable

• Model of dissolved oxygen will help us identify
  optimal irrigation practices
• We are also modeling the effect of EC on stem
  elongation (Collaboration with Dr Loren Oki,
  funded by CAN)

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Remainder of presentation

• Highlight three of the areas of the project
• Example of developing grower tool
• Development of grower tool for rose production
  timing
• Example of research to improve our understanding
• Oxygen in the root zone
• Example of simulation model of nutrients in rose
  production
• Simulation of N and K in rose crop production

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Simulation of N and K in rose production

• Collaboration
• Prof Moshe Silberbush, Israel (2001/2002)
• Dr Wan Soon Kim, South Korea (past and future)
• Mr Neil Mattson, UCDavis (current)
• Objective
• Develop submodel that describes how roses take
  nutrients out of the nutrient solution
• 2001/2002 focus on nitrogen and potassium
• Dr Silberbush worked with me at UCDavis on this
  project

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Simulation of N and K in rose production

• Study uptake of nitrogen (N) and potassium (K) in
  the nutrient solution

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Simulation of N and K in rose production

• Measured N and K in the solution in relation to
  biomass accumulation (roots and shoot)
• Used ion-selective probes
• Used lab techniques to verify results
• Measured root growth

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Simulation of N and K in rose production

• Used results to develop a model
• Assumptions
• No interaction between N and K
• Both N and K involve similar mechanisms for
  removal from solution
• Assume growth is not limited by nutrients
• The model

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Simulation of N and K in rose production
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Simulation of N and K in rose production
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Simulation of N and K in rose production
In this simulation five shoots are simulated to
be on the plant these are harvested at 2-day
intervals. Note pattern of replenishment of
nutrient solution
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Current work

• Identification of temporary storage pools of N
  and K in the plant and how these are related
• Three-dimensional visualization of the plant
• Root growth in relation to root-zone variables
  (moisture, oxygen, nutrients,)
• Combining all the various sub-models into the
  main model

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Simulation software of multiple rose shoots
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Success in leveraging funds

• Modeling work by Lieth and Raviv resulted in
  further funding by BARD (350k /3 years) to focus
  on rose root respiration
• Initiative funding helped convince ICFGA to
  continue supporting rose modeling research (10 -
  20k /year)
• Run-off issues and existing rose modeling work
  led California Association of Nurserymen to
  support rose modeling research (10k - 15k
  /year)
• Sabbatical professor salary (Prof Silberbush)
  multiplied my investment in him 10-fold (60k?)
• Sabbatical government scientist salary (Dr. Hak
  Ki Shin) multiplied my investment in him 10-fold
  (60k?)

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Success in leveraging funds

• Collaborative proposal writing with Dr Wan Soon
  Kim (Korea) resulted in additional funds from
  outside the US into this program
• 63k over next three years
• Dr Kims funded program in Korea (his salary and
  research support there)
• Gifts by industry due to high level of relevancy
  (15k over 3 years)

Continued Floriculture Initiative funding is
needed to assure future success in leveraging
funds from other organization, particularly from
outside the US.
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For more info Professor Heiner Lieth Mail
Environmental Horticulture, University of
California, Davis, CA 95616 E-mail
JHLieth_at_UCDavis.edu Tel [phone] -- Fax
530-752-1819
Web page http//LIETH.ucdavis.edu