African leafy vegetables (ALVs) are mostly gathered from the wild, with few selected species being cultivated, usually as part of a mixed cropping system in home gardens or smallholder plots. They have important advantages over exotic vegetable species, because of their adaptability to marginal agricultural production areas and their ability to provide dietary diversity in poor rural communities. Despite their significance in food and nutrition security, there is limited availability or access to these crops leading to underutilisation. The objective of this review was to document the state of utilisation and production of ALVs in South Africa. A qualitative systematic approach review of online sources, peer reviewed papers published in journals, books and other publications was conducted. There is lack of suitable production systems, innovative processing, and value-adding techniques that promote utilisation of ALVs. Furthermore, there is a perception that ALVs are food for the poor among the youth and urban folks, while, among the affluent, they are highly regarded as being nutritious. To promote ALVs from household consumption and commercialisation, further research on agronomy, post-harvest handling, storage and processing is required in South Africa.

African leafy vegetables (ALVs) are nutrient dense and can contribute to crop and dietary diversity, especially in water-stressed environments. However, research on their productivity under limited water availability remains scant. The objective of the study was to evaluate growth, physiology and yield responses of three ALVs (Vigna unguiculata, Corchorus. Olitorius and Amaranthus cruentus) and a reference vegetable (Beta vulgaris var. cicla) to varying water regimes [30%, 60% and 100% of crop water requirement (ET_c)]. Field trials using a randomised complete block design, replicated three times, were conducted over two summer seasons, 2015/16 and 2016/17. Leaf number, plant height, chlorophyll content index (CCI), chlorophyll fluorescence (CF), and yield were measured in situ. For A. cruentus and C. olitorius, water stress (30% ET_c) was shown to produce a lower yield, although leaf number, plant height and chlorophyll content index were unaffected, while for B. vulgaris, leaf number and yield were reduced by water stress. For V. unguiculata, CF, CCI, plant height, leaf number, and yield were not affected by water stress, indicating its suitability for production in water scarce environments. Using 60% ET_c was suitable for the production of A. cruentus, C. olitorius and B. vulgaris var. cicla, whereas 30% ET_c is recommended for V. unguiculata. The yield results of V. unguiculata indicate that it performs better, while the yield of A. cruentus and C. olitorius is comparable to that of B. vulgaris under similar conditions, indicating potential for marginal production.

Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata are traditional leafy vegetables with potential to improve nutritional security of vulnerable people. The promotion of these crops is partly hindered by the lack of agronomic information. The effect of plant spacing on growth, physiology and yield of these three leafy vegetables was evaluated under commercial-scale production at Roodeplaat, Pretoria over two summer seasons, 2011/12 and 2012/13. A randomised complete block design was used with plant density (100 000, 66 666 and 50 000 plants ha⁻¹) as a factor. Chlorophyll content index (CCI), chlorophyll fluorescence, stomatal conductance, leaf number, leaf area index (LAI) and biomass were measured in situ. Planting at 100 000 plants ha⁻¹ resulted in lower (P < 0.05) LAI, CCI and biomass per plant for A. cruentus and C. olitorius. Total yield of A. cruentus, C. olitorius and V. unguiculata was higher (P < 0.05) at 100 000 plants ha⁻¹ relative to 50 000 and 66 666 plants ha⁻¹. For A. cruentus and C. olitorius, higher leaf attributes (CCI, plant height, leaf number, biomass per plant and LAI) were obtained and this indicated that traditional leafy vegetables can be produced commercially under lower densities using a drip irrigation system. Using 66 666 plants ha⁻¹ is suitable for commercial production of A. cruentus and C. olitorius, whereas 50 000 plants ha⁻¹ may be recommended under low water availability. For V. unguiculata 100 000 plants ha⁻¹ is recommended.