Seasonal Dynamics of Electrical Conductivity on Lettuce Growth in a Nutrient Film Technique Hydroponic System

Authors: ADHIKARI, BIKASH - Mississippi State University; OLORUNWA, OMOLAYO - Bayer Cropscience; WILSON, JEFF - Mississippi State University; Barickman, Thomas - Casey Barickman

Submitted to: Technology in Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2024
Publication Date: 8/16/2024
Citation: Adhikari, B., Olorunwa, O.J., Wilson, J.C., Barickman, T.C. 2024. Seasonal Dynamics of Electrical Conductivity on Lettuce Growth in a Nutrient Film Technique Hydroponic System. Technology in Horticulture. 4:1-7. https://doi.org/10.48130/tihort-0024-0015 .
DOI: https://doi.org/10.48130/tihort-0024-0015

Interpretive Summary: The growing season can heavily influence how specialty crop producers fertilize their lettuce crops, especially in a greenhouse environment. The seasonal changes and the amount of fertilizer are very influential on the nutritional quality and how much marketable fresh weight a producer can get from a lettuce crop. Thus, producers need to pay special attention to the changing of the environment from spring to summer to winter and be able to keenly adjust the fertilizer concentrations depending on these temperature swings. For example, producers need to increase the fertilizer to water concentrations in the winter because the crops grow much slower due to colder temperatures. On the other hand, producers need to lower the fertilizer concentrations in the summer because plants need more water to fertilizer concentrations due tot he rising temperatures to have high quality lettuce heads. In the current study, the authors demonstrate these concepts and determine the fresh and dry weights of the lettuce over different seasons, and how efficient the lettuce plants grow under low to high fertilizer concentrations under these different environment conditions.

Technical Abstract: Lettuce, a staple in worldwide agriculture, has gained widespread acclaim for its adaptability and growing efficiency in hydroponic systems, demonstrating rapid growth cycles and economic significance. Electrical conductivity impacts the growth and physiology of lettuce cultivated under hydroponics. Maintaining the appropriate EC level during the lettuce growth cycle is critical for optimizing hydroponics practices. The greenhouse experiment examined the response of the 'Cegolaine Bibb' lettuce variety in a nutrient film technique hydroponic system throughout three seasons (summer, winter, and spring). The findings revealed significant physiological responses to varying EC levels. Stomatal conductance consistently decreased with rising EC in lettuce grown in summer and spring, indicating plant adaptive mechanisms to varying EC level. Contrarily, lettuce during winter showed an unexpected increase in gs with greater EC, implying a unique seasonal adaptation. Es followed a similar pattern, declining with increasing EC in summer and spring but improving in winter. Furthermore, Tleaf fluctuations across EC levels remained moderate throughout the summer, indicating minimal influences on lettuce temperature regulation. Morphological features, particularly fresh mass (FM), demonstrated a consistent pattern of increased production with higher EC levels in certain seasons, whereas lower EC levels were related to decreased FM. Overall, the study emphasizes the dynamic interrelationships of EC levels and seasonal fluctuations influencing lettuce physiology and morphology. These findings highlight the importance of considering these aspects when optimizing hydroponic environments for increased lettuce growth and yield across seasons.