Growth and Biomass Yield of Lettuce (Lactuca sativa var. Eden) in Aquaponic and Conventional Substrates

Abstract

Background: Lettuce production is essential for food security and urban nutrition in Côte d’Ivoire, but faces challenges related to land scarcity and intensive chemical use. Aquaponics offers a sustainable alternative by combining fish farming and soilless cultivation to enhance productivity with lower environmental impact. Aims: This study aimed to evaluate the growth performance and biomass yield of lettuce (Lactuca sativa var. Eden) cultivated in an aquaponic system compared with coconut fiber enriched with poultry manure and untreated soil as alternative cultivation substrates. Study Design: A comparative experimental design involving three cultivation systems was used. Place and Duration of Study: The experiment was conducted at the experimental facilities of the École Normale Supérieure (ENS), Abidjan, Côte d’Ivoire, over a five-week cultivation period after transplanting. Methodology: Lettuce seedlings were transplanted into three cultivation substrates: an aquaponic system connected to Nile tilapia (Oreochromis niloticus) tanks, coconut fiber enriched with poultry manure, and untreated soil. Growth parameters (plant height, number of leaves, and leaf area) were recorded weekly for four weeks. Fresh and dry biomass yield were measured at harvest. A total of 96 plants per cultivation system were monitored, with biomass assessed on a random sample of 16 plants per treatment. Statistical analyses were performed using the Kruskal-Wallis test followed by Tukey’s test at a 5% significance level. Results: Significant differences were observed among cultivation systems (p < 0.05). Plants grown in the aquaponic system showed the highest growth performance. Mean fresh biomass yield reached 166.79 g per plant compared with 74.62 g and 38.83 g in coconut fiber enriched with poultry manure and untreated soil, respectively. Dry biomass followed the same trend (11.27 g, 6.25 g, and 1.91 g). Conclusion: Aquaponics represents a sustainable technique for lettuce production in urban agriculture systems with limited resources.