Effect of Nutrient Solution Exposure Interval to Magnetic Field on the Growth and Yield of Hydroponically Grown Lettuce (Lactuca sativa)

Objectives: This study explored the effect of the varying nutrient solution exposure intervals to a magnetic field on the growth and yield parameters for lettuce grown in a soilless cultivation system. Method: The study utilized a two-factor factorial experiment arranged in Randomized Complete Block Design (RCBD). The two factors were the number of magnets (Factor A) and nutrient solution exposure intervals (Factor B) to magnetic field. Statistical significance was determined through ANOVA and Tukey’s HSD. Findings: Except for root fresh weight, all growth and yield parameters were significantly influenced by the two factors considered in the study. In addition, annual electrical energy consumption increased by 180-200% when shifting from every-three-day to daily exposure, alongside the increase in frequency of exposure (shorter intervals). However, this was accompanied by a 23.76% improvement in lettuce leaf fresh weight which could justify additional energy expenditure. In conclusion, increasing the number of magnets and increasing frequency of exposure (shorter intervals) resulted in improved lettuce growth and yield performance. Novelty: This study provides novel data on the interaction between magnetization frequency and energy efficiency. The results could be used as a framework for the optimization of the combination of MWT and hydroponics system.