Engineering and Development of a LED narrow wavelength system for plant growth

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As humanity will be challenged with providing food for an estimated 10 billion people by 2050, energy-efficient light-emitting diode (LED) lighting for improved crop production could provide a partial solution to mitigating global food shortages. Understanding how plants grow is imperative to increasing our agricultural output, as a function of light. LEDs are slowly becoming the primary light source in controlled environments. However, high pressure sodium (HPS) are still preferred by most horticulturalists and greenhouse growers. LEDs are superior to HPS lamps and other conventional lighting sources because less energy is required and specific light wavelengths can be selected to improve crop quantity and quality. With the development of LEDs that cover the complete photosynthetically active radiation range (400-700 nm), including ultraviolet and far red/ infrared, it is now possible to determine the impact of narrow wavelengths (< 5 nm) on photosynthesis and plant growth. Yet, most LED manufacturers only provide red and blue LEDs to the horticultural and agricultural industry, with limited wavelengths outside of this spectrum and little consideration for "amber" light, the range emitted by conventional HPS for maximal crop production. The goal of this Discovery proposal is to improve energy-efficient crop production by monitoring plant production and related phenomena, targeting specific light wavelengths that enhance photosynthesis and plant growth to optimize LED technology. This will be accomplished by filtering light to 5 nm of precision and designing light combinations that will enhance plant growth. To achieve this narrow filtering and produce enough light for measuring photosynthesis and plant growth, our first research objective will be to reconfigure a LED narrow wavelength plant growth (LED-NWPG) optical filter system that will select for 5-nm wavelengths emitted by high irradiance LEDs. This system will comprise LED arrays made with optical light fractionating equipment (diffraction gratings, filters and power controller) arranged in a growth chamber that limits external environmental effects. The LEDs will be overpowered and chilled to reach desired irradiance levels required to maintain optimal LED life spans. Plant yield, morphology, photosynthetic efficiency, and metabolite production will be explored in depth using the LED-NWPG. Plants will additionally be monitored in real time to optimize the plant growth environment, allowing for maximal crop production while consuming less energy. The reconfigured LED-NWPG will permit monitoring of light, environment (temperature, humidity, carbon dioxide levels), and plant monitoring (leaf temperature, leaf expansion, transpiration rate). This research will allow for a better understanding of photosynthesis that can be used to develop optimum light recipes to maximize plant production in controlled environments, with the potential to increase food crop quantity and quality.