Eco-designed Recirculating Vertical Aquaponic Lettuce Production System Through Mamdani Fuzzy Logic-Based Adaptive Fertigation

Soilless food production, such as hydroponics, aeroponics and the more complex aquaponics, has been prevalent in urban and peri-urban regions to produce green leafy vegetables for human consumption but to no comprehensive exploration on how it impacts the environment. Adding of synthetic fertilizer in the water system has been the first-hand regiment to compensate for the below-threshold nitrate converted by Nitrosomonas that are suitable for plant growth, however, this causes additional environmental emissions when not properly treated. This study developed an integrated Mamdani Fuzzy Logic-based adaptive fertigation system (FLfert) in a recirculating three-layer partially controlled vertical aquaponics for lettuce and tilapia production which injects the optimum volume of KNO3, NH4H2PO4, and Ca(NO3)2 solutions appropriate to induce the apparent growth and quality of lettuce through a non-invasive vision system that captures leaf images and indirectly measures the nitrate, phosphate, and potassium macronutrients present in the water system. This vision system is embedded with a model that predicts the total chlorophyll concentration, vitamin C, and fresh weight of lettuce which makes the fertigation adaptive as these predicted phenotypes dictate the volume of fertilizer to be injected. The gate-to-gate Life Cycle Assessment confirmed that by implementing FLfert, the environment quality, economical resources, and human toxicity was reduced. Thus, it is recommended for large scale food production.