Nutritive profile of selected leafy vegetables grown on enriched Soilles growing media

This thesis investigated the nutritive profiles of leafy vegetables cultivated on enriched soilless potting growth media under greenhouse conditions, focusing on spinach (Spinacia oleracea L.), cowpea (Vigna unguiculata L. Walp.), amaranth (Amaranthus viridis L.), and collard (Brassica oleracea L.). Three substrate ratios of charcoal dust to coffee husk (2:1, 1:1, 1:2) were combined with three fertilizer treatments Tithonia diversifolia leaf powder, inorganic NPK (15:15:15), and an unfertilized control to evaluate morphological traits, yield and nutrient composition (protein, carbohydrate, fibre, ash, fat, dry matter, and iron). Fertilizer regimes significantly influenced nutrient profiles: inorganic inputs enhanced protein (p= 0.00514) and fibre (p= 0.0372), while organic amendments promoted carbohydrate (p= 0.0319) and iron accumulation. Growth media composition also affected plant responses, with amaranth and collard benefiting most from tailored blends, whereas spinach and cowpea showed resilience across treatments. Cowpea’s adaptability was evident in stable dry matter and consistently high protein, reflecting its nitrogen-fixing capacity. Nutrient outcomes were shaped by both fertilizer type and media composition, highlighting interaction effects. However, ANOVA revealed that growth media, fertilizer treatments, and their interaction did not significantly affect yield (p > 0.05), with species differences accounting for most variation. Overall, the results show that differences in growth media and fertilizer had no significant impact (p >0.05) on dry matter, crude fat, and total ash content, suggesting these traits may be more strongly influenced by genetic variability, environmental conditions, or nutrient interactions. Comparative analysis indicated that soilless systems generally produced higher protein, fibre, and dry matter, while soil-based cultivation yielded greater iron and carbohydrate. In conclusion, integrating waste-derived soilless media with tailored fertilizer regimes offers a scalable and sustainable pathway for leafy vegetable production, with relevance not only for Uganda but also for regions worldwide confronting resource constraints. By advancing resource-efficient cultivation, enriched soilless systems can contribute to global food security and climate-resilient agriculture