Determination of Evapotranspiration Rates for Wheat in Flight by Masterpee

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									Determination of Evapotranspiration
Rates for Wheat in Flight Hardware
      Mock-up Microclimate


             Kimberly Beck
     SLSTP, Texas Woman’s University

 Jessica Prenger, Donna Rouzan-Wheeldon
            Dynamac Corporation

 Howard Levine, Ph.D., Principal Investigator
       NASA, Kennedy Space Center
   Tel: 321-861-3502 Fax: 321-861-3502
    E-mail: Howard.G.Levine@nasa.gov
                                                Fig.1. Kimberly Beck, a 2004 SLSTP
                                                student, setting up the experiment in a
                                                reach-in growth chamber at the SLS
                                                lab. Photograph by Adam Santone.
                 Background
This experiment was part of ground research activity with
the Water Offset Nutrient Delivery ExpeRiment
(WONDER), a mid-deck Space Shuttle payload
investigating crop production for fresh food and advanced
life support. Evaporation and transpiration rates were
measured for wheat grown in a flight hardware type
substrate compartment and environment. Data about water
use and growth rates will be used to develop irrigation
control systems for the WONDER flight experiment.
                            Methods
• 15 wheat seedlings were planted in
  a substrate compartment (SC) with
  granular media and a porous tube
  for nutrient delivery
• SCs were placed in a mock-up flight
  hardware environment: 1) with
  plants (measuring
  evapotranspiration), 2) no plants
  (measuring evaporation) (figure 2)
• SC water balance measured
  evaporation, evapotranspiration,
  and irrigation rates; plant heights
                                        Fig. 2. Experimental set-up of the flight
  were measured to compare              hardware mock-up inside a reach-in
  evapotranspiration rates with         growth chamber. Irrigation lines for the
                                        planted SC are the black tubing on the
  growth                                right. Photograph by Adam Santon.
                                                                                                Results
                                                 DAP 5                          DAP 10                DAP 15                                                      DAP 18                           DAP 24




Fig. 3. Progress of plant growth over time (day after planting (DAP)). Photographs by Jessica Prenger
and Kim Beck.
                                                                                                                                                  12
                                        16
                                                                                                                                                  10
Change in mass (mL per day per plant)




                                                                                                           Transpiration (mL per day per plant)
                                        14         Evaportranspiration                                                                                     WOND 04 08                     R2 = 0.9034
                                                                                                                                                   8
                                                   Evaporation
                                        12
                                                                                                                                                   6
                                        10
                                                                                                                                                   4
                                         8
                                                                                                                                                   2
                                         6
                                                                                                                                                   0
                                         4
                                                                                                                                                  -2
                                         2
                                                                                                                                                  -4
                                         0
                                                                                                                                                  -6
                                             0          5            10               15   20    25
                                                                                                                                                       0     50     100    150      200      250    300   350
                                                                          DAP (day)
                                                                                                                                                                          Avg Growth (mm)

Fig. 4. Transpiration increased over time, and the                                                         Fig. 5. Transpiration rates were directly proportional
decrease in evaporation may be due to change in                                                            to plant growth. A model of water use for the
relative humidity levels.                                                                                  compartments will be developed from measurements
                                                                                                           of growth and microclimate.

								
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