Shading and nitrogen management affect quality, safety and yield of greenhouse-grown leaf lettuce

摘要

Two growing factors (light and nitrogen) supplied at optimal and sub-optimal levels were studied with the aim of evaluating their effects on greenhouse-grown lettuce' biomass and quality performances. According to a split-plot design with three replications, greenhouse lettuce was subjected to sixteen experimental treatments consisting of four photosynthetically active radiation (PAR) availability levels (0, 50, 65 and 85% PAR reduction) and four nitrogen fertilization rates (0, 75, 150 and 300 kg N ha(-1)).