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Crops Models for Varying Environmental ConditionsNew variable environment Modified Energy Cascade (MEC) crop models were developed for all the Advanced Life Support (ALS) candidate crops and implemented in SIMULINK. The MEC models are based on the Volk, Bugbee, and Wheeler Energy Cascade (EC) model and are derived from more recent Top-Level Energy Cascade (TLEC) models. The MEC models simulate crop plant responses to day-to-day changes in photosynthetic photon flux, photoperiod, carbon dioxide level, temperature, and relative humidity. The original EC model allows changes in light energy but uses a less accurate linear approximation. The simulation outputs of the new MEC models for constant nominal environmental conditions are very similar to those of earlier EC models that use parameters produced by the TLEC models. There are a few differences. The new MEC models allow setting the time for seed emergence, have realistic exponential canopy growth, and have corrected harvest dates for potato and tomato. The new MEC models indicate that the maximum edible biomass per meter squared per day is produced at the maximum allowed carbon dioxide level, the nominal temperatures, and the maximum light input. Reducing the carbon dioxide level from the maximum to the minimum allowed in the model reduces crop production significantly. Increasing temperature decreases production more than it decreases the time to harvest, so productivity in edible biomass per meter squared per day is greater at nominal than maximum temperatures, The productivity in edible biomass per meter squared per day is greatest at the maximum light energy input allowed in the model, but the edible biomass produced per light energy input unit is lower than at nominal light levels. Reducing light levels increases light and power use efficiency. The MEC models suggest we can adjust the light energy day-to- day to accommodate power shortages or Lise excess power while monitoring and controlling edible biomass production.
Document ID
20040013151
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Jones, Harry
(NASA Ames Research Center Moffett Field, CA, United States)
Cavazzoni, James
(Rutgers - The State Univ. New Brunswick, NJ, United States)
Keas, Paul
(Orbital Sciences Corp. Moffett Ield, CA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2001
Subject Category
Man/System Technology And Life Support
Meeting Information
Meeting: 32nd International Conference on Environmental Systems
Location: San Antonio, TX
Country: United States
Start Date: July 15, 2002
End Date: July 18, 2002
Funding Number(s)
OTHER: 131-20-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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