Intracanopy lighting reduces electrical energy utilization by closed cowpea stands

Area of Science:

• Plant physiology
• Space agriculture
• Sustainable life support systems

Background:

• High planting densities in space systems create self-shading canopies, limiting light penetration.
• Traditional overhead lighting is inefficient for dense canopies, leading to understory leaf shading.
• Intracanopy lighting offers a solution by distributing light within the plant canopy.

Purpose of the Study:

• To evaluate intracanopy lighting's effectiveness in improving light distribution and crop productivity.
• To compare different fluorescent lamp geometries for optimizing PAR absorption.
• To determine the impact of intracanopy lighting on cowpea growth in simulated space conditions.

Main Methods:

• Comparing fluorescent lamp geometries within cowpea canopies.
• Analyzing leaf orientation plasticity for maximizing photosynthetically active radiation (PAR) absorption.
• Varying lamp density and photosynthetic energy input within canopies.
• Assessing the effects of combined above/within-canopy lighting.

Main Results:

• Cowpea leaves showed plasticity in orientation to maximize PAR absorption from intracanopy lamps.
• Increasing intracanopy lamp density by 38% increased stand productivity by 45%.
• Combined above/within-canopy lighting did not improve PAR interception or yield compared to intracanopy lighting alone.

Conclusions:

• Intracanopy lighting significantly enhances light interception and absorption in dense canopies.
• Optimizing intracanopy lighting is crucial for reducing energy demands in space agriculture.
• This approach holds substantial potential for sustainable food production in future space life support systems.