Phasic temperature and photoperiod control for soybean using a modified CROPGRO model

Area of Science:

• Agricultural Science
• Plant Physiology
• Biotechnology

Background:

• Optimizing soybean production is crucial for NASA's Advanced Life Support program.
• Elevated CO2 levels (1100 micromol mol-1) were used in baseline soybean experiments at Utah State University (USU).

Purpose of the Study:

• To optimize soybean production using a modified CROPGRO model for phased temperature and photoperiod control.
• To evaluate the potential of combined temperature and photoperiod phasing to enhance soybean seed yield.

Main Methods:

• A modified CROPGRO model was employed to simulate soybean growth under different temperature and photoperiod regimes.
• Baseline simulations were established using experimental data from soybean temperature studies at elevated CO2.

Main Results:

• Phasic temperature control alone showed minimal improvement in seed yield rate over existing experimental values.
• Simulations combining phased temperature (two phases) and photoperiod (two phases) indicated a potential 15% increase in seed yield (g m-2 day-1).
• Extending photoperiods during later crop stages may increase seed mass by lengthening grain fill duration.

Conclusions:

• Combined phased temperature and photoperiod control offers a practical strategy to enhance soybean yield for space agriculture.
• Careful management of photoperiod timing and duration is essential to avoid negative impacts on seed number and photosynthesis at elevated CO2.