Integrated Analysis of Physiological, Productive, and Nutritional Response of Hydroponic Chard (Beta vulgaris L. var. Cicla) Under Different Photoperiods and Nutrient Solution Concentrations in a Controlled Environment

Currently, controlled-environment agriculture (CEA) and hydroponic production systems represent sustainable alternatives for improving leafy vegetable production by controlling the variables that influence their growth. This research studied the effect of variations in photoperiod and nutrient solution concentration on the development of a hydroponic crop. The response variables analyzed were growth, physiological response, and nutrient content of chard. The hydroponic cultivation technique used was the Nutrient Film Technique (NFT) under controlled environmental conditions. The experimental design was developed with two photo-period treatments: 12 h light/12 h darkness and 10 h light/14 h darkness, combined with three levels of nutrient concentration at 100%, 75% and 50% of the standard Steiner formulation. The data were analyzed using two complementary approaches: (1) ANOVA with Tukey’s post-hoc test to identify specific group differences, and (2) principal component analysis (PCA). It was observed that the concentration of the nutrient solution had a significant effect on the growth and nutritional quality variables of the crop. Treatments with a 100% nutrient solution resulted in higher values for plant height, biomass, protein, potassium, and calcium. Reducing the nutrient solution concentration resulted in a clear decrease in crop growth variables. The effect of photoperiod on crop development was found to be less significant. The PCA accounted for 96.8% of the total variability. This indicates that nutrient concentration was the primary factor associated with growth and nutritional content in chard. The results show that nutrient reduction directly affects crop productivity and nutritional quality. However, moderate variations in photoperiod had a secondary effect under the conditions evaluated. This research provides relevant information for developing nutritional management strategies and sustainable production in controlled-environment hydroponic systems. It also contributes new knowledge on integrating hydroponic crops in controlled environments into sustainable agri-food systems using Internet of Things (IoT) technologies for efficient crop management.