Studies on Growth and Development of Tomato (Solanum lycopersicum L.) under Aquaponics System in Côte d’Ivoire

Abstract

Aquaponics is the co-culture of fish and plants in a closed-loop, controlled-environment agricultural system. It offers a sustainable and environmentally friendly production system. Evaluating the growth of tomatoes (Solanum lycopersicum L.) in an aquaponics system in Côte d’Ivoire could provide valuable information on the adaptability of this crop to this agricultural system. This study was conducted in the context of increasing land pressure and the search for sustainable agricultural practices in Côte d’Ivoire. It aimed to enhance tomato production by testing the Nutrient Film Technique (NFT) in an aquaponics system. To achieve this, tomato growth in the aquaponics system was compared with cultivation in soil and in a soilless medium of coconut fibre enriched with composted poultry manure. A homogeneous block was established for each growing medium. The experiment was conducted at the École Normale Supérieure (ENS) of Félix HOUPHOUËT-BOIGNY University in Abidjan. The plant material consisted of hybrid tomato seeds of the F1 COBRA 34 variety, and Nile tilapia (Oreochromis niloticus) of Brazilian origin were used in the aquaponics system. Three treatments were established, with 12 plants selected per treatment: T1, unamended soil irrigated with tap water (growing bags filled to 2/3 capacity with soil); T2, an aquaponics system with perforated plastic supports secured with gravel; and T3, coconut fibre plus composted poultry manure (2/3 fibre and 1/3 manure in growing bags). Vegetative growth parameters (height, collar diameter, number of leaves, leaf area, and branching) and floral transition were measured for each treatment. Statistical analysis revealed highly significant differences among treatments in plant height, collar diameter, and leaf area. However, the number of leaves did not differ statistically between plants in the unamended soil treatment (T1) and those in the aquaponics treatment (T2). Tomato plants in the aquaponics system showed the greatest growth, with the highest plant height (43.7 cm), largest collar diameter (6.49 mm), and largest leaf area (193 cm²) compared with those grown in soil and coconut fibre. First flowering occurred 21 days after transplanting in the aquaponics system, earlier than in the soil and coconut-fibre treatments. These results may be related to the composition of the fish-culture water and suggest that aquaponics could represent a sustainable agronomic alternative for improving vegetable production, particularly in urban areas under climate-change conditions. The study highlights the potential of aquaponics to promote crop growth and shorten the time to flowering, thereby contributing to more efficient and environmentally friendly urban agriculture. However, the relatively small sample size (12 plants per treatment) may limit the generalisability of the results. Future studies with larger sample sizes, longer cultivation periods, and further investigation of the plant-to-fish ratio are recommended to validate these findings and assess economic viability.