Growth parameters, maize (Zea mays L.) silage and bambara groundnut (Vigna subterranea L.) grain yield in an intercropping system.
Intercropping is practised throughout the tropics with a range of different crop combinations. As sustainable agriculture includes the enhancement and management of natural resources while meeting the human and animal needs for food/feed and fibre, intercropping has been shown to conserve resources and produce more nutritious food and feed. Therefore, intercropping can contribute to the complex livelihoods of African smallholder farmers by improving their returns on minimal inputs and producing more and quality food per land area. The aim of the study was to evaluate productivity and efficiency of intercropping maize and bambara groundnut, an underutilised legume crop, as alternative dual purpose crops with potential to feed both humans and livestock. Maize (ZM 305) and bambara groundnut landraces were planted in a randomised complete block design (RCBD) consisting of three replications. The experiment consisted of three treatment combinations [sole maize (M), sole bambara groundnut (BG) and maize + bambara groundnut intercrop (MBG)]. Seed quality of both maize and bambara groundnut was determined prior to planting to establish field planting value of seed lots. Data collection included plant growth (leaf number and plant height), physiology (chlorophyll content index and stomatal conductance) and yield and yield components. Intercrop productivity was evaluated using the land equivalent ratio (LER). Maize and bambara groundnut were further analysed for silage properties. The results showed that both maize and bambara groundnut seeds had high seed vigour and viability. There were no differences with respect to growth and physiological parameters of the two crop species. Significant differences (P<0.05) were observed with respect to yield and yield components of bambara groundnut when intercropped with maize. The land equivalent ratio (LER) obtained for the biomass yield of maize was 1.016, which showed an advantage to intercropping. Intercropping increased soil fertility and improved water use efficiency. With respect to the nutrient composition of the two crops, the results obtained were within the range found in the literature. Protein and neutral detergent fibre contents obtained for maize sole crop and intercrop were 7.18% and 7.5% and 77.12% and 70.30%, respectively. For bambara groundnut sole crop and intercrop, the protein and neutral detergent fibre contents obtained were 19.47% and 20.45% and 43.21% and 60.68%, respectively. Despite low yields of bambara groundnut, these findings suggested that intercropping of maize and bambara is advantageous for resource poor smallholder farmers in South Africa.