Currently, many rural economies are locked in subsistence farming and are vulnerable to food insecurity due to lack of access to water, technical know-how and feasible revenue streams, further aggravated by unsustainable farming practices and resulting in migration from rural areas to cities. Climate change negatively affects agricultural production in water-scarce regions of Africa, which makes water use efficiency one of the key factors for agricultural and rural livelihoods. Agriculture is still the most important economic sector in rural Africa and pathways of transition to a circular bioeconomy bears significant potential for socio-economic and environmental sustainability of rural communities in the long term. Revenue diversification pathways in Africa through bio-based and circular agricultural innovations (DIVAGRI) is an EU Horizon2020 funded research projects which includes 39 direct partners. The DIVAGRI consortium has identified a range of major challenges in its target regions and identified solutions to address them within the scope of the project, as summarized in the diagram below.
This presentation will deal with A1, the develop ment of an evaporation greenhouse based on the principle of solar desalination stills. Saltwater is evaporated through open surfaces, and the evaporation increased by cultivating halophytic (salt-tolerant) plants in the desalination greenhouse. A n existing conventional greenhouse wa s retrofitted with a desalination design. DIVAGRI tests passive surface cooling mechanisms to condensate the evaporated water, e.g., low-quality water (e.g. saline groundwater) or seawater, roof cooling mechanisms such as materials, greening of roofs (xerophytes) and shaded/underground area. The combined cooling and humidification with the injection of CO 2 derived from the biorefinery creates optimal growing conditions inside the greenhouse, which could reduce water losses from evapotranspiration by 90% and increase yields by 10-30%. DIVAGRI also investigates cost-efficiencies of the trade-offs between surface area and energy requirement, and design considerations related to local production, operation, and maintenance.