Issues surrounding water scarcity and malnutrition in the rural household of sub-Saharan Africa continue to be a problem and pose threat to food security. In such cases, traditional and underutilized crops have been proposed because of their likely suitability in these marginal areas of crop production characterized by abiotic (drought and heat) and biotic environmental stresses (pest and diseases). Bottle gourd is one such crop with multipurpose use and a huge potential to contribute to food security. The crop is grown for its leaves, fruits, and seeds from landraces providing important nutrition for both humans and livestock. A lot has been documented about its medical properties. The crop exhibits wide genetic variation for qualitative and quantitative traits, which can be used for cultivar development. The objective of this review was to provide information on why bottle gourd is an important food security crop in sub-Saharan Africa. The first section of the paper presents water scarcity, food production, and climate change. This is followed by the section on the neglected underutilized crops species. Then the section of drought tolerance of the crop is presented, and lastly, the section on potential contribution of the crop to food security is presented.

Soil macrofauna are a critical component for ecosystem function and strongly affect production sustainability. The effect of fertiliser management practices, in different cropping systems, on soil macrofauna communities remains poorly understood in semi-arid to arid regions. The objective of this study was to investigate the effect of tillage practices i.e., no-till (NT), rotational tillage (RT) and conventional tillage (CT) and nitrogen fertiliser application rates (0, 100 and 200 kg/ha N) (urea) on abundance and order diversity of soil macrofauna in a maize continuous monocropping system. The sampling of macrofauna in the trial was conducted in April 2019, August 2019 and March 2020 using 25 cm × 25 cm × 25 cm steel monoliths in randomly selected positions, and this was replicated four times. The study found a significant (p < 0.05) increase in the abundance of soil macrofauna in NT (127 ind/m²) and RT (110 ind/m²) compared to CT (51 ind/m²) treatment. The abundance of macrofauna was also negatively affected by increasing the rate of fertiliser, with 0, 100 and 200 kg/ha resulting in 133, 94 and 62 ind/m². Orders Haplotaxida and Diplopoda were found to be sensitive to increases in the fertiliser application rate. Haplotaxida (48.4%) was the most abundant order, followed by Coleoptera (18.2%). Other orders included Diplopoda (9.2%), Gastropoda (6.3%), Isoptera (4.7%), Chilopoda (4.7%), Araneae (4%), Hymenoptera (3.2%), Orthoptera (0.9%) and Dermaptera (0.3%). No-till (NT) and rotational tillage (RT) with mulch favoured the establishment of various macrofauna communities in the studied cropping system.

Knowledge of the long-term complex relationship between soils, crops, and management practices, such as conservation agriculture, is critical in developing nutrient management strategies to optimise crop yields. This study examined the concentration, and the distribution of, soil micronutrients along the soil profile (0–10, 10–20, and 20–30 cm depths) under different tillage practices: no-till (NT), rotational tillage (RT), and conventional tillage (CT), and nitrogen fertilizer application rates (0, 100, 200 kg/ha) in a semi-arid environment after 17 years of implementation of the trial. The results found the lowest concentration (p < 0.05) of copper (Cu) (1.254 mg/kg) and iron (Fe) (22.671 mg/kg) in CT compared to NT [Cu (1.447 mg/kg), Fe (41,156 mg/kg)] and RT [Cu (2.389 mg/kg), Fe (120,437 mg/kg)] treatments. This correlated with the lower soil pH in NT compared to CT treatment, and slightly higher (p > 0.05) under NT (1.782 mg/g) compared to RT (1.715 mg/g) and CT (1.750 mg/g). There were no differences (p > 0.05) in zinc (Zn) in NT (2.856 mg/kg) and RT (2.782 mg/kg) but CT (2.010 mg/kg) treatment was significantly (p < 0.05) lower compared to these treatments. Manganese (Mn) also followed a similar trend whereby CT still had the lowest concentration (p < 0.05) of Mn (8.01 mg/kg) compared to RT (10.71 mg/kg) and NT (11.98 mg/kg). The concentration of Mn, Zn, and Fe was found to be similar (p > 0.05) with an increase in sampling depths. On the other hand, Cu was found to be different (p < 0.05) at different sampling depths. Manganese (10.46 mg/kg) and Soil Organic Carbon (SOC) (2.026 mg/g) were found to be concentrated near the 0–10 cm soil surface depth while Zn (2.558 mg/kg), Fe (66,217 mg/kg) and Cu (1.867 mg/kg) were more at the 20–30 cm depth in reduced tillage treatments. The results also showed no differences (p > 0.05) in the concentration of Cu, Mn, and Zn at different levels of nitrogen fertilizer under all tillage treatments. It was concluded that NT and rational tillage with mulch, favoured the availability of micronutrients (Cu, Mn, Fe, and Zn) in the studied cropping system.

The dynamics of nitrogen availability in soil result from the net amount of organic and inorganic inputs undergoing decomposition, mineralization, and immobilization. This varies with soil type, climate, and cropping system management practices. Hence, the interaction of these factors in a specific environment is important for nitrogen management and availability in any cropping system. This study evaluated the concentration of nitrate (NO₃⁻) and ammonium (NH₄⁺) in a maize monocropping system in a long-term trial under different tillage practices, i.e., no-till (NT), conventional tillage (CT), and rotational tillage (RT), and with different nitrogen (Urea) fertiliser application rates (0, 100, and 200 kg/ha N). The experimental area was a split plot with randomized tillage strips as the main plots, with the nitrogen fertiliser application rates forming the subplots. The results found the highest concentration of NO₃⁻ (7.728 mg/kg) and NH₄⁺ (0.762 mg/kg) under the NT (p < 0.05) compared to the other treatments. CT recorded the lowest amount of NH₄⁺ (0.648 mg/kg) (p < 0.05) compared to RT (0.758 mg/kg), while the concentration of NO₃⁻ (6.755 mg/kg) under the CT was relatively higher than under the RT (4.720 mg/kg). The results also showed that the 0–10 cm depth had a significantly (p < 0.05) higher concentration of NO₃⁻ (6.787 mg/kg) and NH₄⁺ (0.851 mg/kg), followed at the 20–30 cm depth with 6.229 mg/kg NO₃⁻ and 0.832 mg/kg NH₄⁺. Soil samples taken at 10–20 cm depth recorded the lowest NO₃⁻ (6.188 mg/kg) and NH₄⁺ (0.485 mg/kg). The study also found the highest NO₃⁻ concentration (0.452 mg/kg) with 200 kg/ha N (p < 0.05), while the highest concentration of NH₄⁺ (0.954 mg/kg) was found with 0 kg/ha N. The lowest concentrations of both NO₃⁻ (6.333 mg/kg) and NH₄⁺ (0.561 mg/kg) were found with 100 kg/ha N. the no-till also had a significantly (p < 0.05) higher NO₃⁻ (8.518 mg/kg) concentration with 200 kg/ha N compared to the CT (6.005 mg/kg) and RT (4.833 mg/kg). On the other hand, more NH₄⁺ (1.478 mg/kg) was found with 0 kg/ha N under the NT compared to the CT (0.717 mg/kg) and the RT (0.669 mg/kg). The concentration of NH₄⁺ was relatively low with 200 kg/ha N in the NT (0.545 mg/kg) and CT (0.598 mg/kg) but higher in the RT (0.813 mg/kg). In conclusion, the NT favoured the availability of NO₃⁻ and NH₄⁺ in the studied cropping system; however, the concentration of these was affected by fertiliser application rate and depth. This suggested that each tillage system should be compatible with the type and the rate of inorganic nitrogen fertiliser for better crop production.

Maize contamination with aflatoxin B1 (AFB1) is of significance on a global scale due to its major contribution to food security. It is very probable that substantial amounts of AFB1 may be absorbed by germinating seeds grown in contaminated soil and cause deleterious effects on the growth and development of maize. In this study, the effect of green-synthesised ZnO-CuO hybrid nanoparticles (NPs) on antifungal activity and reducing the toxic effects of AFB1 on seed germination was examined. A notable inhibitory effect of green-synthesised ZnO-CuO nanoparticles (NPs) on A. flavus was observed at a concentration of 0.5 ppm, resulting in 13.1% inhibition, which was more effective than the higher concentration of 1.0 ppm and the control. The results showed that the final germination percentage of the seeds that were inoculated with 320 ppb was significantly increased by the treatment with 125 mg/mL of green ZnO-CuO hybrid NPs. This study indicated the potential of green-synthesised ZnO-CuO hybrid NPs as alternative antifungal agents to control aflatoxin production in maize to improve food security and safety by supressing the threat posed by AFB1.

Bottle gourd [Lagenaria siceraria (Molina) Standly] is a neglected underutilized species that is available only as a landrace in sub-Saharan Africa. The objective of this study was to evaluate responses of bottle gourd landraces to water stress compared with pumpkin (Cucurbita maxima) and cucumber (Cucurbita pepo), the closest relatives. For this purpose, two bottle gourd landraces and one green pumpkin cultivar and a cucumber cultivar were grown under controlled conditions at three levels of water stress. Landraces had longer vines than hybrids while hybrid varieties produced more leaves than landraces at all levels of water treatments. The responses of landraces and hybrids to water stress were similar in that they all showed lower chlorophyll content index, stomatal conductance and plant growth in response to decreasing water availability. However, the landraces showed better stomatal regulation indicating better acclimation to water stress. The comparable performance of landraces to the exotic pumpkin and cucumber varieties and their water stress tolerance suggests that bottle gourd could be promoted as an alternative food security crop in rural communities.