Photosynthetic Efficiency and Canopy Architecture Optimization for High-Yield Vegetable Production Under Controlled Environment Agriculture in Nigeria

Controlled environment agriculture (CEA) presents a pathway to year-round, climate-independent vegetable production in Nigerian cities, yet optimizing photosynthetic efficiency and canopy architecture within CEA systems under Nigerian-specific resource and economic constraints has not been systematically investigated. Maximizing light interception, photosynthetic carbon fixation, and biomass partitioning efficiency in CEA vegetable systems is essential for economic viability in a high-energy-cost environment. This dissertation develops and validates canopy architecture optimization models for tomato and lettuce production in controlled environment conditions calibrated to Nigerian solar radiation levels, ambient CO2 concentrations, and economically feasible LED lighting specifications. Process-based crop models (TOMGRO and VegSyst) were adapted and validated using growth chamber experiments at the University of Agriculture, Abeokuta and the University of Ibadan. Model scenarios evaluated density, training, leaf pruning, and supplemental light placement strategies for maximizing radiation use efficiency and marketable yield per unit energy input. Field validation was conducted across three prototype CEA units in Lagos, Abuja, and Enugu. Results indicate that canopy optimization strategies combining moderately high planting density with strategic leaf pruning and lateral LED supplementation can improve radiation use efficiency by 38 percent and increase marketable tomato yield per unit energy input by 25 percent. The study provides validated canopy management guidelines for economically viable CEA vegetable production in Nigeria. Keywords: controlled environment agriculture, photosynthesis, canopy architecture, vegetable production, Nigeria