About 60% of southern Africa’s population lives in rural areas with limited access to basic services and amenities such as clean and safe water, affordable and clean energy, and balanced and nutritious diets. Resource scarcity has direct and indirect impacts on nutrition, human health, and well-being of mostly poor rural communities. Climate change impacts in the region are manifesting through low crop yields, upsurge of vector borne diseases (malaria and dengue fever), and water and food-borne diseases (cholera and diarrhoea). This study applied a water–energy–food (WEF) nexus analytical livelihoods model with complex systems understanding to assess rural livelihoods, health, and well-being in southern Africa, recommending tailor-made adaptation strategies for the region aimed at building resilient rural communities. The WEF nexus is a decision support tool that improves rural livelihoods through integrated resource distribution, planning, and management, and ensures inclusive socio-economic transformation and development, and addresses related sustainable development goals, particularly goals 2, 3, 6 and 7. The integrated WEF nexus index for the region was calculated at 0.145, which is marginally sustainable, and indicating the region’s exposure to vulnerabilities, and reveals a major reason why the region fails to meet its developmental targets. The integrated relationship among WEF resources in southern Africa shows an imbalance and uneven resource allocation, utilisation and distribution, which normally results from a ‘siloed’ approach in resource management. The WEF nexus provides better adaptation options, as it guides decision making processes by identifying priority areas needing intervention, enhancing synergies, and minimising trade-offs necessary for resilient rural communities. Our results identified (i) the trade-offs and unintended negative consequences for poor rural households’ livelihoods of current silo approaches, (ii) mechanisms for sustainably enhancing household water, energy and food security, whilst (iii) providing direction for achieving SDGs 2, 3, 6 and 7.

Increasing agricultural productivity has always been a prominent feature on the regional agenda due to a high incidence of food and nutrition insecurity. This review assessed the current status of irrigated agriculture in southern Africa from a water–energy–food (WEF) nexus perspective. Gaps and opportunities for improving irrigated agriculture within the context of the WEF nexus were also assessed in terms of the feasible limits to which they can be exploited. Southern Africa faces water scarcity, and climate projections show that member states will face increased physical and/or economic water scarcity by as early as 2025, which will have negative impacts on water, energy and food production. Recurrent droughts experienced across the region reaffirm the sensitive issues of food and energy insecurity as well as water scarcity. Projections of an increasing population within the region indicate increased water, energy and food demand. With agriculture already accounting for about 70% of water withdrawals, increasing the area under irrigation will place additional demand on already strained energy grids and scarce water resources. This poses the question—is increasing irrigated agriculture a solution to improving water access, food security and energy supply? While there are prospects for increasing the area under irrigation and subsequent improvement in agricultural productivity, adopting a WEF nexus approach in doing so would mitigate trade-offs and unintended consequences. Consideration of the WEF nexus in integrated resources planning and management eliminates the possibilities of transferring problems from one sector to other, as it manages synergies and trade-offs. While it is acknowledged that improving water productivity in irrigated agriculture could reduce water and energy use while increasing yield output, there is a need to decide how such savings would then be reallocated. Any intervention to increase the irrigated area should be done in the context of a WEF nexus analytical framework to guide policy and decision-making. Technical planning should evolve around the WEF nexus approach in setting targets, as WEF nexus indicators would reveal the performance and impact of proposed interventions on any of the three WEF nexus components.

Sustainable Development Goals (SDGs) acknowledge the inter-linkages between human wellbeing, economic prosperity, and a healthy environment and, hence, are associated with a wide range of topical issues that include the securities of water, energy and food resources, poverty eradication, economic development, climate change, health, among others. As SDGs are assessed through targets to be achieved by 2030 and monitored through measurable indicators, this study applied the nexus planning model to monitor and evaluate progress towards SDGs using South Africa as a case study. The study highlighted pathways to ensure socio-ecological sustainability and environmental health by establishing the connectivity between SDGs and nexus approaches. The linkages between SDGs and nexus planning facilitated the sustainable management of resources in an integrated manner. They addressed the cross-sectoral synergies, value-addition, and trade-offs within interlinked sectors. The connectedness of current challenges facing humankind (climate change, rapid urbanisation, migration, and the emergence of novel infectious diseases) require transformative approaches that address these cross-cutting challenges holistically. Managing the intricate relationships between distinct but interconnected sectors through nexus planning has provided decision support tools to formulate coherent strategies that drive resilience and sustainability. The established linkages between nexus planning and SDGs have strengthened cross-sectoral collaboration and unpacked measures for cooperative governance and management through evidence-based interventions. As food production, water provision, and energy accessibility are the major socio-economic and environmental issues currently attracting global attention; the methodology promotes attaining sustainability by 2030.

The AquaCrop model was calibrated and validated for canola (Brassica napus) under Moistube irrigation (MTI) and various water regimes [(i) 100%, (ii) 75%, and (iii) 55% of crop water requirement (ET_c)] over two seasons, 2019 and 2020. The normalised root mean square (nRMSE), Model Efficiency (EF), R², and the Willmot’s index of agreement (d) statistics were used to evaluate the model’s efficiency in simulating biomass (B), canopy cover (CC), yield (Y), and harvest index (HI). The calibration results indicated the model simulated with accuracy the CC (under 100% ET_cR² = 0.99, EF = 0.92, nRMSE = 6.4%, d = 0.98) and 75% ET_c (R² = 0.99, EF = 0.92, nRMSE = 10.3%, d = 0.98). The model simulated CC well for validation for 100% ET_c (R² = 0.97, EF = 0.93, nRMSE = 22.5%, d = 0.98) and 75% ET_c (R² = 0.84, EF = 0.45, nRMSE = 59.2%, d = 0.86) irrigation regimes. Final biomass simulations were reasonably good under 100% ET_c, 75% ET_c, and 55% ET_c irrigation regimes (R² > 0.90, d > 0.65). The study showed the usefulness of AquaCrop for assessing yield response of canola to full and deficit irrigation scenarios under MTI.

The Buffalo River catchment in KwaZulu-Natal, South Africa, has limited water resource infrastructure development, and climate change is predicted to increase its water supply deficits by exacerbating water distribution inequalities. This study evaluates and optimises current climate change policy plans on the Buffalo River catchments water system to aid in assessing the sustainability of policies that address the aforementioned challenges. The water–energy–food (WEF) nexus approach, which encourages system thinking by considering interconnections among water, energy, and food resources when developing integrated natural resource management strategies, was used to perform the evaluation. The water system's reliability in meeting projected domestic, agricultural, and energy water demands under climate change conditions was used for gauging the sustainability of the development plans. Findings projected the existing water policy plans to increase the domestic water provision by >70% under climate change; however, the 20% under climate change, are thus recommended for future water resource management research and dialogue in the Buffalo River catchment.

Efficient agricultural water management (AWM) practices enhance crop water productivity and promote climate change adaptation and resilience initiatives, particularly in smallholder farming systems. Approximately 90% of sub-Saharan Africa’s (SSA) agriculture is rainfed under smallholder farmers who constitute about 60% of the continent’s population and depend on agriculture for their livelihoods. While AWM is central to the African agenda, knowledge of AWM is fragmented, making it challenging to operationalize regional initiatives at country levels. Therefore, this study sought to review the status of AWM practices and technologies in Africa and provide guidelines, scenarios, and investment plans to guide the prioritization and operationalization of the African Union’s irrigation development and AWM (AU-IDAWM) initiative. The initiative proposes four developmental pathways; 1—improved water control and watershed management in rain-fed farming, 2—farmer-led irrigation, 3—irrigation scheme development and modernization, and 4—unconventional water use for irrigation. The preferred reporting items for systematic reviews and meta-analyses approach guided the systematic literature review. The study indicates that most agricultural production systems are mainly under pathways 1 and 2, which dictate the subsequent AWM practices. Pathway 4 had isolated adoption in North Africa. SSA exhibited overlaps in opportunities for AWM, whereas North Africa had green energy and strong extension services. The challenges were unique to each geopolitical region. Policy-related issues affected North Africa, whilst low investment in AWM dominated West Africa. Poor institutional coordination plagued East Africa, whilst low access to extension services affected Southern Africa. The Central African region was undermined by poor management practices that culminated in soil salinity in the agricultural lands. Targeted and scalable investments across interventions are necessary topotentially improve AWM uptake and subsequent food security in the continent. Also, institutional setups are essential in coordinating efforts towards achieving AWM. Extension services are essential information dissemination platforms for adopting effective climate-smart agriculture.