Influence of the spectral composition of LED lighting system on plants cultivation in a darkroom

Agriculture is one of the most important areas of the world economy. However, due to dependency on weather conditions, it is strongly industrialized, for example by introducing additional lighting improving the efficiency of plants growth. Construction and operation of light-emitting diodes provides new possibilities in research and application of new concepts in agricultural lighting.
The aim of the work was to investigate the effect of various spectra of light on the efficiency of photosynthesis and the growth of selected species of plants. For this purpose two grow-boxes with dedicated LED-based lighting systems were constructed and placed in the darkroom with controlled temperature. In each box lighting system provided different spectral composition of light and it was possible to adjust the ratio of blue and red as well as the irradiance level.
In the paper we present the construction of the grow-boxes and the results of 3 cycles of experiments conducted with this system. During the first cycle two groups of tested plants were cultivated in the LED grow-boxes with constant irradiance level and the third group in natural light conditions. During the second cycle the irradiance in both boxes was gradually increased from 8W/m2 to 38W/m2. During the third cycle the irradiance was set to 38 W/m2 during the whole period (max power MRED module) to get the maximum possible intensity of photosynthesis.

This research was conducted with financing from the statutory work S/WE/4/2013 (Ministry of Science and Higher Education Republic of Poland) in the Department of Electric Power Engineering, Photonics and Lighting Technology, Bialystok University of Technology.