New gardens in the Sahara: a "Citizen Science" project at the University of Bayreuth

The gardens are designed as models of sustainable horticulture. They strengthen the food security of the people in Tibesti and help them earn additional income through the sale of agricultural products. "The Sahara Gardens are a participatory project that involved local residents from the beginning. They have actively contributed to the construction of the gardens by using their own resources, for example in procuring materials for well construction or building fences," explains project manager Dr. habil. Tilman Musch. He emphasizes that the aim of the project is not to implement supposedly universal solutions for horticulture in the desert. This is not possible, he says, if only because the environmental conditions for farming in Tibesti vary greatly over a small area.

Until the 1960s, cereals, tomatoes and date palms were cultivated in the oases of Tibesti. However, as a result of migration and wars, agriculture increasingly fell into oblivion. When selecting sites for the new gardens, linking to this tradition was an important criterion. However, the aim now was not simply a revival, but an innovative design of the gardens with a view to sustainability, climate change and practical agricultural techniques.

Three challenges in particular had to be overcome: The first priority was to develop water sources. The construction of costly deep wells did not seem desirable because it would centralize access to water and encourage water waste. Instead, open wells and boreholes were installed in conjunction with modern solar-powered pumps. It turned out that all these forms of water development have both advantages and disadvantages and often serve very different purposes at the same time – not only the irrigation of the gardens, but also the drinking water supply or the water for goat and sheep herds.

Sustainable irrigation of the gardens, which ensures the most efficient possible use of the available water supplies, was another key project objective. Instead of purchasing costly drip irrigation systems that lead to technical dependencies and are often subject to rapid wear and tear, the project team opted in many cases for conventional forms of irrigation that were improved in terms of sustainability. "We are still in dialogue with the local population about ways to optimize these traditionally common irrigation methods," Musch explains. In addition, he and his team have successfully tested a technique on site that has not yet been used in the Saharan oases: Subirrigation with porous but robust bead hoses has been shown to result in very economical water consumption.

The third challenge was to avoid large-scale use of pesticides and artificial fertilizers and to avoid dependence on global seed markets. Therefore, local garden operators were provided with seed-stable seeds selected under two criteria: The plant species should be able to thrive in the climatic conditions of the Central Sahara and their fruits should be so clearly distinguishable to the eye that no elaborate documentation is needed to identify them. The local gardeners will retain those fruit and vegetable varieties that seem best adapted to them and propagate them in a targeted manner. This may result in varieties that are even better adapted to local soil, weather, and climate conditions.

Background information:
The Tibesti Mountains, with an altitude of up to about 3,500 m, are the highest mountains in the Central Sahara. They are characterized by volcanism and were a refuge for plants and animals during the drying up of the Sahara over thousands of years. The watershed between the basins of Lake Chad and the Mediterranean runs through the central Tibesti. To establish the new Saharan gardens at the remote project sites, the required materials had to be transported on unpaved roads over a total distance of more than 1,600 km across the desert, which was the broadest challenge of this pioneering project.

Publication:
Tilman Musch: Saharagärten.Ein landwirtschaftliches Pionierprojekt im Tibesti-Gebirge (Zentralsahara). Berichte über Landwirtschaft. Zeitschrift für Agrarpolitik und Landwirtschaft (2023). https://buel.bmel.de/index.php/buel/article/view/475