Abstract:
To improve the diet of rural families, small scale production of leafy vegetables, as a source of vitamin A and other nutrients should be encouraged. In this study, conducted under controlled environmental conditions (day temperatures in the greenhouse varied between 22 and 29°C with night temperatures between 13 and 16°C), Beta vulgaris (Swiss chard) and Amaranthus spp. (imbuya) were grown, using gravel and pumice as substrates for 'Ebb-and-Flood' and 'constant level' production systems. The results of this study showed that a combination of an 'Ebb-and-Flood' system with gravel as substrate, gave the best results of root development and leaf yield, especially for 'imbuya'. The water-use-efficiency (WUE) of 'imbuya' was significantly higher than that of Swiss chard. The yield and leaf chlorophyll content of 'imbuya' was low for the 'constant level' system with gravel used as substrate. Pumice improved root production, leaf yield and leaf chlorophyll content only for the 'constant level' system, probably owing to capillary action in pumice and associated improved root aeration.